3084 lines
136 KiB
XML
3084 lines
136 KiB
XML
<?xml version='1.0' encoding='UTF-8'?>
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<?xml-stylesheet type="text/xsl"
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href="http://docbook.sourceforge.net/release/xsl/current/manpages/docbook.xsl"?>
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.4//EN"
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"http://www.oasis-open.org/docbook/xml/4.4/docbookx.dtd" [
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]>
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<refentry>
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<refentryinfo>
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<title>User Manual</title>
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<productname>jemalloc</productname>
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<releaseinfo role="version">@jemalloc_version@</releaseinfo>
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<authorgroup>
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<author>
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<firstname>Jason</firstname>
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<surname>Evans</surname>
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<personblurb>Author</personblurb>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>JEMALLOC</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refdescriptor>jemalloc</refdescriptor>
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<refname>jemalloc</refname>
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<!-- Each refname causes a man page file to be created. Only if this were
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the system malloc(3) implementation would these files be appropriate.
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<refname>malloc</refname>
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<refname>calloc</refname>
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<refname>posix_memalign</refname>
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<refname>aligned_alloc</refname>
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<refname>realloc</refname>
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<refname>free</refname>
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<refname>mallocx</refname>
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<refname>rallocx</refname>
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<refname>xallocx</refname>
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<refname>sallocx</refname>
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<refname>dallocx</refname>
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<refname>sdallocx</refname>
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<refname>nallocx</refname>
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<refname>mallctl</refname>
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<refname>mallctlnametomib</refname>
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<refname>mallctlbymib</refname>
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<refname>malloc_stats_print</refname>
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<refname>malloc_usable_size</refname>
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-->
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<refpurpose>general purpose memory allocation functions</refpurpose>
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</refnamediv>
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<refsect1 id="library">
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<title>LIBRARY</title>
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<para>This manual describes jemalloc @jemalloc_version@. More information
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can be found at the <ulink
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url="http://jemalloc.net/">jemalloc website</ulink>.</para>
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</refsect1>
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<refsynopsisdiv>
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<title>SYNOPSIS</title>
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<funcsynopsis>
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<funcsynopsisinfo>#include <<filename class="headerfile">jemalloc/jemalloc.h</filename>></funcsynopsisinfo>
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<refsect2>
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<title>Standard API</title>
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<funcprototype>
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<funcdef>void *<function>malloc</function></funcdef>
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<paramdef>size_t <parameter>size</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>void *<function>calloc</function></funcdef>
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<paramdef>size_t <parameter>number</parameter></paramdef>
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<paramdef>size_t <parameter>size</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>posix_memalign</function></funcdef>
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<paramdef>void **<parameter>ptr</parameter></paramdef>
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<paramdef>size_t <parameter>alignment</parameter></paramdef>
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<paramdef>size_t <parameter>size</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>void *<function>aligned_alloc</function></funcdef>
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<paramdef>size_t <parameter>alignment</parameter></paramdef>
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<paramdef>size_t <parameter>size</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>void *<function>realloc</function></funcdef>
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<paramdef>void *<parameter>ptr</parameter></paramdef>
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<paramdef>size_t <parameter>size</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>void <function>free</function></funcdef>
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<paramdef>void *<parameter>ptr</parameter></paramdef>
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</funcprototype>
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</refsect2>
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<refsect2>
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<title>Non-standard API</title>
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<funcprototype>
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<funcdef>void *<function>mallocx</function></funcdef>
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<paramdef>size_t <parameter>size</parameter></paramdef>
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<paramdef>int <parameter>flags</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>void *<function>rallocx</function></funcdef>
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<paramdef>void *<parameter>ptr</parameter></paramdef>
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<paramdef>size_t <parameter>size</parameter></paramdef>
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<paramdef>int <parameter>flags</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>size_t <function>xallocx</function></funcdef>
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<paramdef>void *<parameter>ptr</parameter></paramdef>
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<paramdef>size_t <parameter>size</parameter></paramdef>
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<paramdef>size_t <parameter>extra</parameter></paramdef>
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<paramdef>int <parameter>flags</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>size_t <function>sallocx</function></funcdef>
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<paramdef>void *<parameter>ptr</parameter></paramdef>
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<paramdef>int <parameter>flags</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>void <function>dallocx</function></funcdef>
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<paramdef>void *<parameter>ptr</parameter></paramdef>
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<paramdef>int <parameter>flags</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>void <function>sdallocx</function></funcdef>
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<paramdef>void *<parameter>ptr</parameter></paramdef>
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<paramdef>size_t <parameter>size</parameter></paramdef>
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<paramdef>int <parameter>flags</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>size_t <function>nallocx</function></funcdef>
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<paramdef>size_t <parameter>size</parameter></paramdef>
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<paramdef>int <parameter>flags</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>mallctl</function></funcdef>
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<paramdef>const char *<parameter>name</parameter></paramdef>
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<paramdef>void *<parameter>oldp</parameter></paramdef>
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<paramdef>size_t *<parameter>oldlenp</parameter></paramdef>
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<paramdef>void *<parameter>newp</parameter></paramdef>
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<paramdef>size_t <parameter>newlen</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>mallctlnametomib</function></funcdef>
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<paramdef>const char *<parameter>name</parameter></paramdef>
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<paramdef>size_t *<parameter>mibp</parameter></paramdef>
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<paramdef>size_t *<parameter>miblenp</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>mallctlbymib</function></funcdef>
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<paramdef>const size_t *<parameter>mib</parameter></paramdef>
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<paramdef>size_t <parameter>miblen</parameter></paramdef>
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<paramdef>void *<parameter>oldp</parameter></paramdef>
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<paramdef>size_t *<parameter>oldlenp</parameter></paramdef>
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<paramdef>void *<parameter>newp</parameter></paramdef>
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<paramdef>size_t <parameter>newlen</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>void <function>malloc_stats_print</function></funcdef>
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<paramdef>void <parameter>(*write_cb)</parameter>
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<funcparams>void *, const char *</funcparams>
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</paramdef>
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<paramdef>void *<parameter>cbopaque</parameter></paramdef>
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<paramdef>const char *<parameter>opts</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>size_t <function>malloc_usable_size</function></funcdef>
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<paramdef>const void *<parameter>ptr</parameter></paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>void <function>(*malloc_message)</function></funcdef>
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<paramdef>void *<parameter>cbopaque</parameter></paramdef>
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<paramdef>const char *<parameter>s</parameter></paramdef>
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</funcprototype>
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<para><type>const char *</type><varname>malloc_conf</varname>;</para>
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</refsect2>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1 id="description">
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<title>DESCRIPTION</title>
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<refsect2>
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<title>Standard API</title>
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<para>The <function>malloc()</function> function allocates
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<parameter>size</parameter> bytes of uninitialized memory. The allocated
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space is suitably aligned (after possible pointer coercion) for storage
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of any type of object.</para>
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<para>The <function>calloc()</function> function allocates
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space for <parameter>number</parameter> objects, each
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<parameter>size</parameter> bytes in length. The result is identical to
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calling <function>malloc()</function> with an argument of
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<parameter>number</parameter> * <parameter>size</parameter>, with the
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exception that the allocated memory is explicitly initialized to zero
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bytes.</para>
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<para>The <function>posix_memalign()</function> function
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allocates <parameter>size</parameter> bytes of memory such that the
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allocation's base address is a multiple of
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<parameter>alignment</parameter>, and returns the allocation in the value
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pointed to by <parameter>ptr</parameter>. The requested
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<parameter>alignment</parameter> must be a power of 2 at least as large as
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<code language="C">sizeof(<type>void *</type>)</code>.</para>
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<para>The <function>aligned_alloc()</function> function
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allocates <parameter>size</parameter> bytes of memory such that the
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allocation's base address is a multiple of
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<parameter>alignment</parameter>. The requested
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<parameter>alignment</parameter> must be a power of 2. Behavior is
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undefined if <parameter>size</parameter> is not an integral multiple of
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<parameter>alignment</parameter>.</para>
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<para>The <function>realloc()</function> function changes the
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size of the previously allocated memory referenced by
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<parameter>ptr</parameter> to <parameter>size</parameter> bytes. The
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contents of the memory are unchanged up to the lesser of the new and old
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sizes. If the new size is larger, the contents of the newly allocated
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portion of the memory are undefined. Upon success, the memory referenced
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by <parameter>ptr</parameter> is freed and a pointer to the newly
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allocated memory is returned. Note that
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<function>realloc()</function> may move the memory allocation,
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resulting in a different return value than <parameter>ptr</parameter>.
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If <parameter>ptr</parameter> is <constant>NULL</constant>, the
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<function>realloc()</function> function behaves identically to
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<function>malloc()</function> for the specified size.</para>
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<para>The <function>free()</function> function causes the
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allocated memory referenced by <parameter>ptr</parameter> to be made
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available for future allocations. If <parameter>ptr</parameter> is
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<constant>NULL</constant>, no action occurs.</para>
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</refsect2>
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<refsect2>
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<title>Non-standard API</title>
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<para>The <function>mallocx()</function>,
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<function>rallocx()</function>,
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<function>xallocx()</function>,
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<function>sallocx()</function>,
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<function>dallocx()</function>,
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<function>sdallocx()</function>, and
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<function>nallocx()</function> functions all have a
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<parameter>flags</parameter> argument that can be used to specify
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options. The functions only check the options that are contextually
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relevant. Use bitwise or (<code language="C">|</code>) operations to
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specify one or more of the following:
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<variablelist>
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<varlistentry id="MALLOCX_LG_ALIGN">
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<term><constant>MALLOCX_LG_ALIGN(<parameter>la</parameter>)
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</constant></term>
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<listitem><para>Align the memory allocation to start at an address
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that is a multiple of <code language="C">(1 <<
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<parameter>la</parameter>)</code>. This macro does not validate
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that <parameter>la</parameter> is within the valid
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range.</para></listitem>
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</varlistentry>
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<varlistentry id="MALLOCX_ALIGN">
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<term><constant>MALLOCX_ALIGN(<parameter>a</parameter>)
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</constant></term>
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<listitem><para>Align the memory allocation to start at an address
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that is a multiple of <parameter>a</parameter>, where
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<parameter>a</parameter> is a power of two. This macro does not
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validate that <parameter>a</parameter> is a power of 2.
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</para></listitem>
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</varlistentry>
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<varlistentry id="MALLOCX_ZERO">
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<term><constant>MALLOCX_ZERO</constant></term>
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<listitem><para>Initialize newly allocated memory to contain zero
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bytes. In the growing reallocation case, the real size prior to
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reallocation defines the boundary between untouched bytes and those
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that are initialized to contain zero bytes. If this macro is
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absent, newly allocated memory is uninitialized.</para></listitem>
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</varlistentry>
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<varlistentry id="MALLOCX_TCACHE">
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<term><constant>MALLOCX_TCACHE(<parameter>tc</parameter>)
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</constant></term>
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<listitem><para>Use the thread-specific cache (tcache) specified by
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the identifier <parameter>tc</parameter>, which must have been
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acquired via the <link
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linkend="tcache.create"><mallctl>tcache.create</mallctl></link>
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mallctl. This macro does not validate that
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<parameter>tc</parameter> specifies a valid
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identifier.</para></listitem>
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</varlistentry>
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<varlistentry id="MALLOC_TCACHE_NONE">
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<term><constant>MALLOCX_TCACHE_NONE</constant></term>
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<listitem><para>Do not use a thread-specific cache (tcache). Unless
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<constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant> or
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<constant>MALLOCX_TCACHE_NONE</constant> is specified, an
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automatically managed tcache will be used under many circumstances.
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This macro cannot be used in the same <parameter>flags</parameter>
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argument as
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<constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant>.</para></listitem>
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</varlistentry>
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<varlistentry id="MALLOCX_ARENA">
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<term><constant>MALLOCX_ARENA(<parameter>a</parameter>)
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</constant></term>
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<listitem><para>Use the arena specified by the index
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<parameter>a</parameter>. This macro has no effect for regions that
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were allocated via an arena other than the one specified. This
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macro does not validate that <parameter>a</parameter> specifies an
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arena index in the valid range.</para></listitem>
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</varlistentry>
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</variablelist>
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</para>
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<para>The <function>mallocx()</function> function allocates at
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least <parameter>size</parameter> bytes of memory, and returns a pointer
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to the base address of the allocation. Behavior is undefined if
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<parameter>size</parameter> is <constant>0</constant>.</para>
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<para>The <function>rallocx()</function> function resizes the
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allocation at <parameter>ptr</parameter> to be at least
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<parameter>size</parameter> bytes, and returns a pointer to the base
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address of the resulting allocation, which may or may not have moved from
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its original location. Behavior is undefined if
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<parameter>size</parameter> is <constant>0</constant>.</para>
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<para>The <function>xallocx()</function> function resizes the
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allocation at <parameter>ptr</parameter> in place to be at least
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<parameter>size</parameter> bytes, and returns the real size of the
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allocation. If <parameter>extra</parameter> is non-zero, an attempt is
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made to resize the allocation to be at least <code
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language="C">(<parameter>size</parameter> +
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<parameter>extra</parameter>)</code> bytes, though inability to allocate
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the extra byte(s) will not by itself result in failure to resize.
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Behavior is undefined if <parameter>size</parameter> is
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<constant>0</constant>, or if <code
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language="C">(<parameter>size</parameter> + <parameter>extra</parameter>
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> <constant>SIZE_T_MAX</constant>)</code>.</para>
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<para>The <function>sallocx()</function> function returns the
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real size of the allocation at <parameter>ptr</parameter>.</para>
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<para>The <function>dallocx()</function> function causes the
|
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memory referenced by <parameter>ptr</parameter> to be made available for
|
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future allocations.</para>
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<para>The <function>sdallocx()</function> function is an
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extension of <function>dallocx()</function> with a
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<parameter>size</parameter> parameter to allow the caller to pass in the
|
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allocation size as an optimization. The minimum valid input size is the
|
|
original requested size of the allocation, and the maximum valid input
|
|
size is the corresponding value returned by
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<function>nallocx()</function> or
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<function>sallocx()</function>.</para>
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<para>The <function>nallocx()</function> function allocates no
|
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memory, but it performs the same size computation as the
|
|
<function>mallocx()</function> function, and returns the real
|
|
size of the allocation that would result from the equivalent
|
|
<function>mallocx()</function> function call, or
|
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<constant>0</constant> if the inputs exceed the maximum supported size
|
|
class and/or alignment. Behavior is undefined if
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<parameter>size</parameter> is <constant>0</constant>.</para>
|
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<para>The <function>mallctl()</function> function provides a
|
|
general interface for introspecting the memory allocator, as well as
|
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setting modifiable parameters and triggering actions. The
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|
period-separated <parameter>name</parameter> argument specifies a
|
|
location in a tree-structured namespace; see the <xref
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|
linkend="mallctl_namespace" xrefstyle="template:%t"/> section for
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|
documentation on the tree contents. To read a value, pass a pointer via
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<parameter>oldp</parameter> to adequate space to contain the value, and a
|
|
pointer to its length via <parameter>oldlenp</parameter>; otherwise pass
|
|
<constant>NULL</constant> and <constant>NULL</constant>. Similarly, to
|
|
write a value, pass a pointer to the value via
|
|
<parameter>newp</parameter>, and its length via
|
|
<parameter>newlen</parameter>; otherwise pass <constant>NULL</constant>
|
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and <constant>0</constant>.</para>
|
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|
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<para>The <function>mallctlnametomib()</function> function
|
|
provides a way to avoid repeated name lookups for applications that
|
|
repeatedly query the same portion of the namespace, by translating a name
|
|
to a <quote>Management Information Base</quote> (MIB) that can be passed
|
|
repeatedly to <function>mallctlbymib()</function>. Upon
|
|
successful return from <function>mallctlnametomib()</function>,
|
|
<parameter>mibp</parameter> contains an array of
|
|
<parameter>*miblenp</parameter> integers, where
|
|
<parameter>*miblenp</parameter> is the lesser of the number of components
|
|
in <parameter>name</parameter> and the input value of
|
|
<parameter>*miblenp</parameter>. Thus it is possible to pass a
|
|
<parameter>*miblenp</parameter> that is smaller than the number of
|
|
period-separated name components, which results in a partial MIB that can
|
|
be used as the basis for constructing a complete MIB. For name
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|
components that are integers (e.g. the 2 in
|
|
<link
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linkend="arenas.bin.i.size"><mallctl>arenas.bin.2.size</mallctl></link>),
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the corresponding MIB component will always be that integer. Therefore,
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|
it is legitimate to construct code like the following: <programlisting
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language="C"><![CDATA[
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unsigned nbins, i;
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size_t mib[4];
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size_t len, miblen;
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len = sizeof(nbins);
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mallctl("arenas.nbins", &nbins, &len, NULL, 0);
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miblen = 4;
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mallctlnametomib("arenas.bin.0.size", mib, &miblen);
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for (i = 0; i < nbins; i++) {
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size_t bin_size;
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mib[2] = i;
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len = sizeof(bin_size);
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mallctlbymib(mib, miblen, (void *)&bin_size, &len, NULL, 0);
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/* Do something with bin_size... */
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|
}]]></programlisting></para>
|
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|
|
<para>The <function>malloc_stats_print()</function> function writes
|
|
summary statistics via the <parameter>write_cb</parameter> callback
|
|
function pointer and <parameter>cbopaque</parameter> data passed to
|
|
<parameter>write_cb</parameter>, or <function>malloc_message()</function>
|
|
if <parameter>write_cb</parameter> is <constant>NULL</constant>. The
|
|
statistics are presented in human-readable form unless <quote>J</quote> is
|
|
specified as a character within the <parameter>opts</parameter> string, in
|
|
which case the statistics are presented in <ulink
|
|
url="http://www.json.org/">JSON format</ulink>. This function can be
|
|
called repeatedly. General information that never changes during
|
|
execution can be omitted by specifying <quote>g</quote> as a character
|
|
within the <parameter>opts</parameter> string. Note that
|
|
<function>malloc_message()</function> uses the
|
|
<function>mallctl*()</function> functions internally, so inconsistent
|
|
statistics can be reported if multiple threads use these functions
|
|
simultaneously. If <option>--enable-stats</option> is specified during
|
|
configuration, <quote>m</quote>, <quote>d</quote>, and <quote>a</quote>
|
|
can be specified to omit merged arena, destroyed merged arena, and per
|
|
arena statistics, respectively; <quote>b</quote> and <quote>l</quote> can
|
|
be specified to omit per size class statistics for bins and large objects,
|
|
respectively; <quote>x</quote> can be specified to omit all mutex
|
|
statistics. Unrecognized characters are silently ignored. Note that
|
|
thread caching may prevent some statistics from being completely up to
|
|
date, since extra locking would be required to merge counters that track
|
|
thread cache operations.</para>
|
|
|
|
<para>The <function>malloc_usable_size()</function> function
|
|
returns the usable size of the allocation pointed to by
|
|
<parameter>ptr</parameter>. The return value may be larger than the size
|
|
that was requested during allocation. The
|
|
<function>malloc_usable_size()</function> function is not a
|
|
mechanism for in-place <function>realloc()</function>; rather
|
|
it is provided solely as a tool for introspection purposes. Any
|
|
discrepancy between the requested allocation size and the size reported
|
|
by <function>malloc_usable_size()</function> should not be
|
|
depended on, since such behavior is entirely implementation-dependent.
|
|
</para>
|
|
</refsect2>
|
|
</refsect1>
|
|
<refsect1 id="tuning">
|
|
<title>TUNING</title>
|
|
<para>Once, when the first call is made to one of the memory allocation
|
|
routines, the allocator initializes its internals based in part on various
|
|
options that can be specified at compile- or run-time.</para>
|
|
|
|
<para>The string specified via <option>--with-malloc-conf</option>, the
|
|
string pointed to by the global variable <varname>malloc_conf</varname>, the
|
|
<quote>name</quote> of the file referenced by the symbolic link named
|
|
<filename class="symlink">/etc/malloc.conf</filename>, and the value of the
|
|
environment variable <envar>MALLOC_CONF</envar>, will be interpreted, in
|
|
that order, from left to right as options. Note that
|
|
<varname>malloc_conf</varname> may be read before
|
|
<function>main()</function> is entered, so the declaration of
|
|
<varname>malloc_conf</varname> should specify an initializer that contains
|
|
the final value to be read by jemalloc. <option>--with-malloc-conf</option>
|
|
and <varname>malloc_conf</varname> are compile-time mechanisms, whereas
|
|
<filename class="symlink">/etc/malloc.conf</filename> and
|
|
<envar>MALLOC_CONF</envar> can be safely set any time prior to program
|
|
invocation.</para>
|
|
|
|
<para>An options string is a comma-separated list of option:value pairs.
|
|
There is one key corresponding to each <link
|
|
linkend="opt.abort"><mallctl>opt.*</mallctl></link> mallctl (see the <xref
|
|
linkend="mallctl_namespace" xrefstyle="template:%t"/> section for options
|
|
documentation). For example, <literal>abort:true,narenas:1</literal> sets
|
|
the <link linkend="opt.abort"><mallctl>opt.abort</mallctl></link> and <link
|
|
linkend="opt.narenas"><mallctl>opt.narenas</mallctl></link> options. Some
|
|
options have boolean values (true/false), others have integer values (base
|
|
8, 10, or 16, depending on prefix), and yet others have raw string
|
|
values.</para>
|
|
</refsect1>
|
|
<refsect1 id="implementation_notes">
|
|
<title>IMPLEMENTATION NOTES</title>
|
|
<para>Traditionally, allocators have used
|
|
<citerefentry><refentrytitle>sbrk</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry> to obtain memory, which is
|
|
suboptimal for several reasons, including race conditions, increased
|
|
fragmentation, and artificial limitations on maximum usable memory. If
|
|
<citerefentry><refentrytitle>sbrk</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry> is supported by the operating
|
|
system, this allocator uses both
|
|
<citerefentry><refentrytitle>mmap</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry> and
|
|
<citerefentry><refentrytitle>sbrk</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry>, in that order of preference;
|
|
otherwise only <citerefentry><refentrytitle>mmap</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry> is used.</para>
|
|
|
|
<para>This allocator uses multiple arenas in order to reduce lock
|
|
contention for threaded programs on multi-processor systems. This works
|
|
well with regard to threading scalability, but incurs some costs. There is
|
|
a small fixed per-arena overhead, and additionally, arenas manage memory
|
|
completely independently of each other, which means a small fixed increase
|
|
in overall memory fragmentation. These overheads are not generally an
|
|
issue, given the number of arenas normally used. Note that using
|
|
substantially more arenas than the default is not likely to improve
|
|
performance, mainly due to reduced cache performance. However, it may make
|
|
sense to reduce the number of arenas if an application does not make much
|
|
use of the allocation functions.</para>
|
|
|
|
<para>In addition to multiple arenas, unless
|
|
<option>--disable-tcache</option> is specified during configuration, this
|
|
allocator supports thread-specific caching, in order to make it possible to
|
|
completely avoid synchronization for most allocation requests. Such caching
|
|
allows very fast allocation in the common case, but it increases memory
|
|
usage and fragmentation, since a bounded number of objects can remain
|
|
allocated in each thread cache.</para>
|
|
|
|
<para>Memory is conceptually broken into extents. Extents are always
|
|
aligned to multiples of the page size. This alignment makes it possible to
|
|
find metadata for user objects quickly. User objects are broken into two
|
|
categories according to size: small and large. Contiguous small objects
|
|
comprise a slab, which resides within a single extent, whereas large objects
|
|
each have their own extents backing them.</para>
|
|
|
|
<para>Small objects are managed in groups by slabs. Each slab maintains
|
|
a bitmap to track which regions are in use. Allocation requests that are no
|
|
more than half the quantum (8 or 16, depending on architecture) are rounded
|
|
up to the nearest power of two that is at least <code
|
|
language="C">sizeof(<type>double</type>)</code>. All other object size
|
|
classes are multiples of the quantum, spaced such that there are four size
|
|
classes for each doubling in size, which limits internal fragmentation to
|
|
approximately 20% for all but the smallest size classes. Small size classes
|
|
are smaller than four times the page size, and large size classes extend
|
|
from four times the page size up to the largest size class that does not
|
|
exceed <constant>PTRDIFF_MAX</constant>.</para>
|
|
|
|
<para>Allocations are packed tightly together, which can be an issue for
|
|
multi-threaded applications. If you need to assure that allocations do not
|
|
suffer from cacheline sharing, round your allocation requests up to the
|
|
nearest multiple of the cacheline size, or specify cacheline alignment when
|
|
allocating.</para>
|
|
|
|
<para>The <function>realloc()</function>,
|
|
<function>rallocx()</function>, and
|
|
<function>xallocx()</function> functions may resize allocations
|
|
without moving them under limited circumstances. Unlike the
|
|
<function>*allocx()</function> API, the standard API does not
|
|
officially round up the usable size of an allocation to the nearest size
|
|
class, so technically it is necessary to call
|
|
<function>realloc()</function> to grow e.g. a 9-byte allocation to
|
|
16 bytes, or shrink a 16-byte allocation to 9 bytes. Growth and shrinkage
|
|
trivially succeeds in place as long as the pre-size and post-size both round
|
|
up to the same size class. No other API guarantees are made regarding
|
|
in-place resizing, but the current implementation also tries to resize large
|
|
allocations in place, as long as the pre-size and post-size are both large.
|
|
For shrinkage to succeed, the extent allocator must support splitting (see
|
|
<link
|
|
linkend="arena.i.extent_hooks"><mallctl>arena.<i>.extent_hooks</mallctl></link>).
|
|
Growth only succeeds if the trailing memory is currently available, and the
|
|
extent allocator supports merging.</para>
|
|
|
|
<para>Assuming 4 KiB pages and a 16-byte quantum on a 64-bit system, the
|
|
size classes in each category are as shown in <xref linkend="size_classes"
|
|
xrefstyle="template:Table %n"/>.</para>
|
|
|
|
<table xml:id="size_classes" frame="all">
|
|
<title>Size classes</title>
|
|
<tgroup cols="3" colsep="1" rowsep="1">
|
|
<colspec colname="c1" align="left"/>
|
|
<colspec colname="c2" align="right"/>
|
|
<colspec colname="c3" align="left"/>
|
|
<thead>
|
|
<row>
|
|
<entry>Category</entry>
|
|
<entry>Spacing</entry>
|
|
<entry>Size</entry>
|
|
</row>
|
|
</thead>
|
|
<tbody>
|
|
<row>
|
|
<entry morerows="8">Small</entry>
|
|
<entry>lg</entry>
|
|
<entry>[8]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>16</entry>
|
|
<entry>[16, 32, 48, 64, 80, 96, 112, 128]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>32</entry>
|
|
<entry>[160, 192, 224, 256]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>64</entry>
|
|
<entry>[320, 384, 448, 512]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>128</entry>
|
|
<entry>[640, 768, 896, 1024]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>256</entry>
|
|
<entry>[1280, 1536, 1792, 2048]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>512</entry>
|
|
<entry>[2560, 3072, 3584, 4096]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>1 KiB</entry>
|
|
<entry>[5 KiB, 6 KiB, 7 KiB, 8 KiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>2 KiB</entry>
|
|
<entry>[10 KiB, 12 KiB, 14 KiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry morerows="15">Large</entry>
|
|
<entry>2 KiB</entry>
|
|
<entry>[16 KiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>4 KiB</entry>
|
|
<entry>[20 KiB, 24 KiB, 28 KiB, 32 KiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>8 KiB</entry>
|
|
<entry>[40 KiB, 48 KiB, 54 KiB, 64 KiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>16 KiB</entry>
|
|
<entry>[80 KiB, 96 KiB, 112 KiB, 128 KiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>32 KiB</entry>
|
|
<entry>[160 KiB, 192 KiB, 224 KiB, 256 KiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>64 KiB</entry>
|
|
<entry>[320 KiB, 384 KiB, 448 KiB, 512 KiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>128 KiB</entry>
|
|
<entry>[640 KiB, 768 KiB, 896 KiB, 1 MiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>256 KiB</entry>
|
|
<entry>[1280 KiB, 1536 KiB, 1792 KiB, 2 MiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>512 KiB</entry>
|
|
<entry>[2560 KiB, 3 MiB, 3584 KiB, 4 MiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>1 MiB</entry>
|
|
<entry>[5 MiB, 6 MiB, 7 MiB, 8 MiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>2 MiB</entry>
|
|
<entry>[10 MiB, 12 MiB, 14 MiB, 16 MiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>4 MiB</entry>
|
|
<entry>[20 MiB, 24 MiB, 28 MiB, 32 MiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>8 MiB</entry>
|
|
<entry>[40 MiB, 48 MiB, 56 MiB, 64 MiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>...</entry>
|
|
<entry>...</entry>
|
|
</row>
|
|
<row>
|
|
<entry>512 PiB</entry>
|
|
<entry>[2560 PiB, 3 EiB, 3584 PiB, 4 EiB]</entry>
|
|
</row>
|
|
<row>
|
|
<entry>1 EiB</entry>
|
|
<entry>[5 EiB, 6 EiB, 7 EiB]</entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</table>
|
|
</refsect1>
|
|
<refsect1 id="mallctl_namespace">
|
|
<title>MALLCTL NAMESPACE</title>
|
|
<para>The following names are defined in the namespace accessible via the
|
|
<function>mallctl*()</function> functions. Value types are specified in
|
|
parentheses, their readable/writable statuses are encoded as
|
|
<literal>rw</literal>, <literal>r-</literal>, <literal>-w</literal>, or
|
|
<literal>--</literal>, and required build configuration flags follow, if
|
|
any. A name element encoded as <literal><i></literal> or
|
|
<literal><j></literal> indicates an integer component, where the
|
|
integer varies from 0 to some upper value that must be determined via
|
|
introspection. In the case of <mallctl>stats.arenas.<i>.*</mallctl>
|
|
and <mallctl>arena.<i>.{initialized,purge,decay,dss}</mallctl>,
|
|
<literal><i></literal> equal to
|
|
<constant>MALLCTL_ARENAS_ALL</constant> can be used to operate on all arenas
|
|
or access the summation of statistics from all arenas; similarly
|
|
<literal><i></literal> equal to
|
|
<constant>MALLCTL_ARENAS_DESTROYED</constant> can be used to access the
|
|
summation of statistics from all destroyed arenas. These constants can be
|
|
utilized either via <function>mallctlnametomib()</function> followed by
|
|
<function>mallctlbymib()</function>, or via code such as the following:
|
|
<programlisting language="C"><![CDATA[
|
|
#define STRINGIFY_HELPER(x) #x
|
|
#define STRINGIFY(x) STRINGIFY_HELPER(x)
|
|
|
|
mallctl("arena." STRINGIFY(MALLCTL_ARENAS_ALL) ".decay",
|
|
NULL, NULL, NULL, 0);]]></programlisting>
|
|
Take special note of the <link
|
|
linkend="epoch"><mallctl>epoch</mallctl></link> mallctl, which controls
|
|
refreshing of cached dynamic statistics.</para>
|
|
|
|
<variablelist>
|
|
<varlistentry id="version">
|
|
<term>
|
|
<mallctl>version</mallctl>
|
|
(<type>const char *</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Return the jemalloc version string.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="epoch">
|
|
<term>
|
|
<mallctl>epoch</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>rw</literal>
|
|
</term>
|
|
<listitem><para>If a value is passed in, refresh the data from which
|
|
the <function>mallctl*()</function> functions report values,
|
|
and increment the epoch. Return the current epoch. This is useful for
|
|
detecting whether another thread caused a refresh.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.cache_oblivious">
|
|
<term>
|
|
<mallctl>config.cache_oblivious</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--enable-cache-oblivious</option> was specified
|
|
during build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.debug">
|
|
<term>
|
|
<mallctl>config.debug</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--enable-debug</option> was specified during
|
|
build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.fill">
|
|
<term>
|
|
<mallctl>config.fill</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--enable-fill</option> was specified during
|
|
build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.lazy_lock">
|
|
<term>
|
|
<mallctl>config.lazy_lock</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--enable-lazy-lock</option> was specified
|
|
during build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.malloc_conf">
|
|
<term>
|
|
<mallctl>config.malloc_conf</mallctl>
|
|
(<type>const char *</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Embedded configure-time-specified run-time options
|
|
string, empty unless <option>--with-malloc-conf</option> was specified
|
|
during build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.munmap">
|
|
<term>
|
|
<mallctl>config.munmap</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--enable-munmap</option> was specified during
|
|
build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.prof">
|
|
<term>
|
|
<mallctl>config.prof</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--enable-prof</option> was specified during
|
|
build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.prof_libgcc">
|
|
<term>
|
|
<mallctl>config.prof_libgcc</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--disable-prof-libgcc</option> was not
|
|
specified during build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.prof_libunwind">
|
|
<term>
|
|
<mallctl>config.prof_libunwind</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--enable-prof-libunwind</option> was specified
|
|
during build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.stats">
|
|
<term>
|
|
<mallctl>config.stats</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--enable-stats</option> was specified during
|
|
build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.tcache">
|
|
<term>
|
|
<mallctl>config.tcache</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--disable-tcache</option> was not specified
|
|
during build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.tls">
|
|
<term>
|
|
<mallctl>config.tls</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--disable-tls</option> was not specified during
|
|
build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.utrace">
|
|
<term>
|
|
<mallctl>config.utrace</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--enable-utrace</option> was specified during
|
|
build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="config.xmalloc">
|
|
<term>
|
|
<mallctl>config.xmalloc</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para><option>--enable-xmalloc</option> was specified during
|
|
build configuration.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.abort">
|
|
<term>
|
|
<mallctl>opt.abort</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Abort-on-warning enabled/disabled. If true, most
|
|
warnings are fatal. The process will call
|
|
<citerefentry><refentrytitle>abort</refentrytitle>
|
|
<manvolnum>3</manvolnum></citerefentry> in these cases. This option is
|
|
disabled by default unless <option>--enable-debug</option> is
|
|
specified during configuration, in which case it is enabled by default.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.dss">
|
|
<term>
|
|
<mallctl>opt.dss</mallctl>
|
|
(<type>const char *</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>dss (<citerefentry><refentrytitle>sbrk</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry>) allocation precedence as
|
|
related to <citerefentry><refentrytitle>mmap</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry> allocation. The following
|
|
settings are supported if
|
|
<citerefentry><refentrytitle>sbrk</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry> is supported by the operating
|
|
system: <quote>disabled</quote>, <quote>primary</quote>, and
|
|
<quote>secondary</quote>; otherwise only <quote>disabled</quote> is
|
|
supported. The default is <quote>secondary</quote> if
|
|
<citerefentry><refentrytitle>sbrk</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry> is supported by the operating
|
|
system; <quote>disabled</quote> otherwise.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.narenas">
|
|
<term>
|
|
<mallctl>opt.narenas</mallctl>
|
|
(<type>unsigned</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Maximum number of arenas to use for automatic
|
|
multiplexing of threads and arenas. The default is four times the
|
|
number of CPUs, or one if there is a single CPU.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.percpu_arena">
|
|
<term>
|
|
<mallctl>opt.percpu_arena</mallctl>
|
|
(<type>const char *</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Per CPU arena mode. Use the <quote>percpu</quote>
|
|
setting to enable this feature, which uses number of CPUs to determine
|
|
number of arenas, and bind threads to arenas dynamically based on the
|
|
CPU the thread runs on currently. <quote>phycpu</quote> setting uses
|
|
one arena per physical CPU, which means the two hyper threads on the
|
|
same CPU share one arena. Note that no runtime checking regarding the
|
|
availability of hyper threading is done at the moment. When set to
|
|
<quote>disabled</quote>, narenas and thread to arena association will
|
|
not be impacted by this option. The default is
|
|
<quote>percpu</quote>. </para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.dirty_decay_time">
|
|
<term>
|
|
<mallctl>opt.dirty_decay_time</mallctl>
|
|
(<type>ssize_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Approximate time in seconds from the creation of a set
|
|
of unused dirty pages until an equivalent set of unused dirty pages is
|
|
purged (i.e. converted to muzzy via e.g.
|
|
<function>madvise(<parameter>...</parameter><parameter><constant>MADV_FREE</constant></parameter>)</function>
|
|
if supported by the operating system, or converted to clean otherwise)
|
|
and/or reused. Dirty pages are defined as previously having been
|
|
potentially written to by the application, and therefore consuming
|
|
physical memory, yet having no current use. The pages are incrementally
|
|
purged according to a sigmoidal decay curve that starts and ends with
|
|
zero purge rate. A decay time of 0 causes all unused dirty pages to be
|
|
purged immediately upon creation. A decay time of -1 disables purging.
|
|
The default decay time is 10 seconds. See <link
|
|
linkend="arenas.dirty_decay_time"><mallctl>arenas.dirty_decay_time</mallctl></link>
|
|
and <link
|
|
linkend="arena.i.muzzy_decay_time"><mallctl>arena.<i>.muzzy_decay_time</mallctl></link>
|
|
for related dynamic control options. See <link
|
|
linkend="opt.muzzy_decay_time"><mallctl>opt.muzzy_decay_time</mallctl></link>
|
|
for a description of muzzy pages.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.muzzy_decay_time">
|
|
<term>
|
|
<mallctl>opt.muzzy_decay_time</mallctl>
|
|
(<type>ssize_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Approximate time in seconds from the creation of a set
|
|
of unused muzzy pages until an equivalent set of unused muzzy pages is
|
|
purged (i.e. converted to clean) and/or reused. Muzzy pages are defined
|
|
as previously having been unused dirty pages that were subsequently
|
|
purged in a manner that left them subject to the reclamation whims of
|
|
the operating system (e.g.
|
|
<function>madvise(<parameter>...</parameter><parameter><constant>MADV_FREE</constant></parameter>)</function>),
|
|
and therefore in an indeterminate state. The pages are incrementally
|
|
purged according to a sigmoidal decay curve that starts and ends with
|
|
zero purge rate. A decay time of 0 causes all unused muzzy pages to be
|
|
purged immediately upon creation. A decay time of -1 disables purging.
|
|
The default decay time is 10 seconds. See <link
|
|
linkend="arenas.muzzy_decay_time"><mallctl>arenas.muzzy_decay_time</mallctl></link>
|
|
and <link
|
|
linkend="arena.i.muzzy_decay_time"><mallctl>arena.<i>.muzzy_decay_time</mallctl></link>
|
|
for related dynamic control options.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.stats_print">
|
|
<term>
|
|
<mallctl>opt.stats_print</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Enable/disable statistics printing at exit. If
|
|
enabled, the <function>malloc_stats_print()</function>
|
|
function is called at program exit via an
|
|
<citerefentry><refentrytitle>atexit</refentrytitle>
|
|
<manvolnum>3</manvolnum></citerefentry> function. If
|
|
<option>--enable-stats</option> is specified during configuration, this
|
|
has the potential to cause deadlock for a multi-threaded process that
|
|
exits while one or more threads are executing in the memory allocation
|
|
functions. Furthermore, <function>atexit()</function> may
|
|
allocate memory during application initialization and then deadlock
|
|
internally when jemalloc in turn calls
|
|
<function>atexit()</function>, so this option is not
|
|
universally usable (though the application can register its own
|
|
<function>atexit()</function> function with equivalent
|
|
functionality). Therefore, this option should only be used with care;
|
|
it is primarily intended as a performance tuning aid during application
|
|
development. This option is disabled by default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.junk">
|
|
<term>
|
|
<mallctl>opt.junk</mallctl>
|
|
(<type>const char *</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-fill</option>]
|
|
</term>
|
|
<listitem><para>Junk filling. If set to <quote>alloc</quote>, each byte
|
|
of uninitialized allocated memory will be initialized to
|
|
<literal>0xa5</literal>. If set to <quote>free</quote>, all deallocated
|
|
memory will be initialized to <literal>0x5a</literal>. If set to
|
|
<quote>true</quote>, both allocated and deallocated memory will be
|
|
initialized, and if set to <quote>false</quote>, junk filling be
|
|
disabled entirely. This is intended for debugging and will impact
|
|
performance negatively. This option is <quote>false</quote> by default
|
|
unless <option>--enable-debug</option> is specified during
|
|
configuration, in which case it is <quote>true</quote> by
|
|
default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.zero">
|
|
<term>
|
|
<mallctl>opt.zero</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-fill</option>]
|
|
</term>
|
|
<listitem><para>Zero filling enabled/disabled. If enabled, each byte
|
|
of uninitialized allocated memory will be initialized to 0. Note that
|
|
this initialization only happens once for each byte, so
|
|
<function>realloc()</function> and
|
|
<function>rallocx()</function> calls do not zero memory that
|
|
was previously allocated. This is intended for debugging and will
|
|
impact performance negatively. This option is disabled by default.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.utrace">
|
|
<term>
|
|
<mallctl>opt.utrace</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-utrace</option>]
|
|
</term>
|
|
<listitem><para>Allocation tracing based on
|
|
<citerefentry><refentrytitle>utrace</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry> enabled/disabled. This option
|
|
is disabled by default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.xmalloc">
|
|
<term>
|
|
<mallctl>opt.xmalloc</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-xmalloc</option>]
|
|
</term>
|
|
<listitem><para>Abort-on-out-of-memory enabled/disabled. If enabled,
|
|
rather than returning failure for any allocation function, display a
|
|
diagnostic message on <constant>STDERR_FILENO</constant> and cause the
|
|
program to drop core (using
|
|
<citerefentry><refentrytitle>abort</refentrytitle>
|
|
<manvolnum>3</manvolnum></citerefentry>). If an application is
|
|
designed to depend on this behavior, set the option at compile time by
|
|
including the following in the source code:
|
|
<programlisting language="C"><![CDATA[
|
|
malloc_conf = "xmalloc:true";]]></programlisting>
|
|
This option is disabled by default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.tcache">
|
|
<term>
|
|
<mallctl>opt.tcache</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Thread-specific caching (tcache) enabled/disabled. When
|
|
there are multiple threads, each thread uses a tcache for objects up to
|
|
a certain size. Thread-specific caching allows many allocations to be
|
|
satisfied without performing any thread synchronization, at the cost of
|
|
increased memory use. See the <link
|
|
linkend="opt.lg_tcache_max"><mallctl>opt.lg_tcache_max</mallctl></link>
|
|
option for related tuning information. This option is enabled by
|
|
default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.lg_tcache_max">
|
|
<term>
|
|
<mallctl>opt.lg_tcache_max</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Maximum size class (log base 2) to cache in the
|
|
thread-specific cache (tcache). At a minimum, all small size classes
|
|
are cached, and at a maximum all large size classes are cached. The
|
|
default maximum is 32 KiB (2^15).</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.prof">
|
|
<term>
|
|
<mallctl>opt.prof</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Memory profiling enabled/disabled. If enabled, profile
|
|
memory allocation activity. See the <link
|
|
linkend="opt.prof_active"><mallctl>opt.prof_active</mallctl></link>
|
|
option for on-the-fly activation/deactivation. See the <link
|
|
linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link>
|
|
option for probabilistic sampling control. See the <link
|
|
linkend="opt.prof_accum"><mallctl>opt.prof_accum</mallctl></link>
|
|
option for control of cumulative sample reporting. See the <link
|
|
linkend="opt.lg_prof_interval"><mallctl>opt.lg_prof_interval</mallctl></link>
|
|
option for information on interval-triggered profile dumping, the <link
|
|
linkend="opt.prof_gdump"><mallctl>opt.prof_gdump</mallctl></link>
|
|
option for information on high-water-triggered profile dumping, and the
|
|
<link linkend="opt.prof_final"><mallctl>opt.prof_final</mallctl></link>
|
|
option for final profile dumping. Profile output is compatible with
|
|
the <command>jeprof</command> command, which is based on the
|
|
<command>pprof</command> that is developed as part of the <ulink
|
|
url="http://code.google.com/p/gperftools/">gperftools
|
|
package</ulink>. See <link linkend="heap_profile_format">HEAP PROFILE
|
|
FORMAT</link> for heap profile format documentation.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.prof_prefix">
|
|
<term>
|
|
<mallctl>opt.prof_prefix</mallctl>
|
|
(<type>const char *</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Filename prefix for profile dumps. If the prefix is
|
|
set to the empty string, no automatic dumps will occur; this is
|
|
primarily useful for disabling the automatic final heap dump (which
|
|
also disables leak reporting, if enabled). The default prefix is
|
|
<filename>jeprof</filename>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.prof_active">
|
|
<term>
|
|
<mallctl>opt.prof_active</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Profiling activated/deactivated. This is a secondary
|
|
control mechanism that makes it possible to start the application with
|
|
profiling enabled (see the <link
|
|
linkend="opt.prof"><mallctl>opt.prof</mallctl></link> option) but
|
|
inactive, then toggle profiling at any time during program execution
|
|
with the <link
|
|
linkend="prof.active"><mallctl>prof.active</mallctl></link> mallctl.
|
|
This option is enabled by default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.prof_thread_active_init">
|
|
<term>
|
|
<mallctl>opt.prof_thread_active_init</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Initial setting for <link
|
|
linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link>
|
|
in newly created threads. The initial setting for newly created threads
|
|
can also be changed during execution via the <link
|
|
linkend="prof.thread_active_init"><mallctl>prof.thread_active_init</mallctl></link>
|
|
mallctl. This option is enabled by default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.lg_prof_sample">
|
|
<term>
|
|
<mallctl>opt.lg_prof_sample</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Average interval (log base 2) between allocation
|
|
samples, as measured in bytes of allocation activity. Increasing the
|
|
sampling interval decreases profile fidelity, but also decreases the
|
|
computational overhead. The default sample interval is 512 KiB (2^19
|
|
B).</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.prof_accum">
|
|
<term>
|
|
<mallctl>opt.prof_accum</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Reporting of cumulative object/byte counts in profile
|
|
dumps enabled/disabled. If this option is enabled, every unique
|
|
backtrace must be stored for the duration of execution. Depending on
|
|
the application, this can impose a large memory overhead, and the
|
|
cumulative counts are not always of interest. This option is disabled
|
|
by default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.lg_prof_interval">
|
|
<term>
|
|
<mallctl>opt.lg_prof_interval</mallctl>
|
|
(<type>ssize_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Average interval (log base 2) between memory profile
|
|
dumps, as measured in bytes of allocation activity. The actual
|
|
interval between dumps may be sporadic because decentralized allocation
|
|
counters are used to avoid synchronization bottlenecks. Profiles are
|
|
dumped to files named according to the pattern
|
|
<filename><prefix>.<pid>.<seq>.i<iseq>.heap</filename>,
|
|
where <literal><prefix></literal> is controlled by the
|
|
<link
|
|
linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link>
|
|
option. By default, interval-triggered profile dumping is disabled
|
|
(encoded as -1).
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.prof_gdump">
|
|
<term>
|
|
<mallctl>opt.prof_gdump</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Set the initial state of <link
|
|
linkend="prof.gdump"><mallctl>prof.gdump</mallctl></link>, which when
|
|
enabled triggers a memory profile dump every time the total virtual
|
|
memory exceeds the previous maximum. This option is disabled by
|
|
default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.prof_final">
|
|
<term>
|
|
<mallctl>opt.prof_final</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Use an
|
|
<citerefentry><refentrytitle>atexit</refentrytitle>
|
|
<manvolnum>3</manvolnum></citerefentry> function to dump final memory
|
|
usage to a file named according to the pattern
|
|
<filename><prefix>.<pid>.<seq>.f.heap</filename>,
|
|
where <literal><prefix></literal> is controlled by the <link
|
|
linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link>
|
|
option. Note that <function>atexit()</function> may allocate
|
|
memory during application initialization and then deadlock internally
|
|
when jemalloc in turn calls <function>atexit()</function>, so
|
|
this option is not universally usable (though the application can
|
|
register its own <function>atexit()</function> function with
|
|
equivalent functionality). This option is disabled by
|
|
default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="opt.prof_leak">
|
|
<term>
|
|
<mallctl>opt.prof_leak</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Leak reporting enabled/disabled. If enabled, use an
|
|
<citerefentry><refentrytitle>atexit</refentrytitle>
|
|
<manvolnum>3</manvolnum></citerefentry> function to report memory leaks
|
|
detected by allocation sampling. See the
|
|
<link linkend="opt.prof"><mallctl>opt.prof</mallctl></link> option for
|
|
information on analyzing heap profile output. This option is disabled
|
|
by default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="thread.arena">
|
|
<term>
|
|
<mallctl>thread.arena</mallctl>
|
|
(<type>unsigned</type>)
|
|
<literal>rw</literal>
|
|
</term>
|
|
<listitem><para>Get or set the arena associated with the calling
|
|
thread. If the specified arena was not initialized beforehand (see the
|
|
<link
|
|
linkend="arena.i.initialized"><mallctl>arena.i.initialized</mallctl></link>
|
|
mallctl), it will be automatically initialized as a side effect of
|
|
calling this interface.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="thread.allocated">
|
|
<term>
|
|
<mallctl>thread.allocated</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Get the total number of bytes ever allocated by the
|
|
calling thread. This counter has the potential to wrap around; it is
|
|
up to the application to appropriately interpret the counter in such
|
|
cases.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="thread.allocatedp">
|
|
<term>
|
|
<mallctl>thread.allocatedp</mallctl>
|
|
(<type>uint64_t *</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Get a pointer to the the value that is returned by the
|
|
<link
|
|
linkend="thread.allocated"><mallctl>thread.allocated</mallctl></link>
|
|
mallctl. This is useful for avoiding the overhead of repeated
|
|
<function>mallctl*()</function> calls.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="thread.deallocated">
|
|
<term>
|
|
<mallctl>thread.deallocated</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Get the total number of bytes ever deallocated by the
|
|
calling thread. This counter has the potential to wrap around; it is
|
|
up to the application to appropriately interpret the counter in such
|
|
cases.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="thread.deallocatedp">
|
|
<term>
|
|
<mallctl>thread.deallocatedp</mallctl>
|
|
(<type>uint64_t *</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Get a pointer to the the value that is returned by the
|
|
<link
|
|
linkend="thread.deallocated"><mallctl>thread.deallocated</mallctl></link>
|
|
mallctl. This is useful for avoiding the overhead of repeated
|
|
<function>mallctl*()</function> calls.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="thread.tcache.enabled">
|
|
<term>
|
|
<mallctl>thread.tcache.enabled</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>rw</literal>
|
|
[<option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Enable/disable calling thread's tcache. The tcache is
|
|
implicitly flushed as a side effect of becoming
|
|
disabled (see <link
|
|
linkend="thread.tcache.flush"><mallctl>thread.tcache.flush</mallctl></link>).
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="thread.tcache.flush">
|
|
<term>
|
|
<mallctl>thread.tcache.flush</mallctl>
|
|
(<type>void</type>)
|
|
<literal>--</literal>
|
|
[<option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Flush calling thread's thread-specific cache (tcache).
|
|
This interface releases all cached objects and internal data structures
|
|
associated with the calling thread's tcache. Ordinarily, this interface
|
|
need not be called, since automatic periodic incremental garbage
|
|
collection occurs, and the thread cache is automatically discarded when
|
|
a thread exits. However, garbage collection is triggered by allocation
|
|
activity, so it is possible for a thread that stops
|
|
allocating/deallocating to retain its cache indefinitely, in which case
|
|
the developer may find manual flushing useful.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="thread.prof.name">
|
|
<term>
|
|
<mallctl>thread.prof.name</mallctl>
|
|
(<type>const char *</type>)
|
|
<literal>r-</literal> or
|
|
<literal>-w</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Get/set the descriptive name associated with the calling
|
|
thread in memory profile dumps. An internal copy of the name string is
|
|
created, so the input string need not be maintained after this interface
|
|
completes execution. The output string of this interface should be
|
|
copied for non-ephemeral uses, because multiple implementation details
|
|
can cause asynchronous string deallocation. Furthermore, each
|
|
invocation of this interface can only read or write; simultaneous
|
|
read/write is not supported due to string lifetime limitations. The
|
|
name string must be nil-terminated and comprised only of characters in
|
|
the sets recognized
|
|
by <citerefentry><refentrytitle>isgraph</refentrytitle>
|
|
<manvolnum>3</manvolnum></citerefentry> and
|
|
<citerefentry><refentrytitle>isblank</refentrytitle>
|
|
<manvolnum>3</manvolnum></citerefentry>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="thread.prof.active">
|
|
<term>
|
|
<mallctl>thread.prof.active</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>rw</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Control whether sampling is currently active for the
|
|
calling thread. This is an activation mechanism in addition to <link
|
|
linkend="prof.active"><mallctl>prof.active</mallctl></link>; both must
|
|
be active for the calling thread to sample. This flag is enabled by
|
|
default.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="tcache.create">
|
|
<term>
|
|
<mallctl>tcache.create</mallctl>
|
|
(<type>unsigned</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Create an explicit thread-specific cache (tcache) and
|
|
return an identifier that can be passed to the <link
|
|
linkend="MALLOCX_TCACHE"><constant>MALLOCX_TCACHE(<parameter>tc</parameter>)</constant></link>
|
|
macro to explicitly use the specified cache rather than the
|
|
automatically managed one that is used by default. Each explicit cache
|
|
can be used by only one thread at a time; the application must assure
|
|
that this constraint holds.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="tcache.flush">
|
|
<term>
|
|
<mallctl>tcache.flush</mallctl>
|
|
(<type>unsigned</type>)
|
|
<literal>-w</literal>
|
|
[<option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Flush the specified thread-specific cache (tcache). The
|
|
same considerations apply to this interface as to <link
|
|
linkend="thread.tcache.flush"><mallctl>thread.tcache.flush</mallctl></link>,
|
|
except that the tcache will never be automatically discarded.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="tcache.destroy">
|
|
<term>
|
|
<mallctl>tcache.destroy</mallctl>
|
|
(<type>unsigned</type>)
|
|
<literal>-w</literal>
|
|
[<option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Flush the specified thread-specific cache (tcache) and
|
|
make the identifier available for use during a future tcache creation.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arena.i.initialized">
|
|
<term>
|
|
<mallctl>arena.<i>.initialized</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Get whether the specified arena's statistics are
|
|
initialized (i.e. the arena was initialized prior to the current epoch).
|
|
This interface can also be nominally used to query whether the merged
|
|
statistics corresponding to <constant>MALLCTL_ARENAS_ALL</constant> are
|
|
initialized (always true).</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arena.i.decay">
|
|
<term>
|
|
<mallctl>arena.<i>.decay</mallctl>
|
|
(<type>void</type>)
|
|
<literal>--</literal>
|
|
</term>
|
|
<listitem><para>Trigger decay-based purging of unused dirty/muzzy pages
|
|
for arena <i>, or for all arenas if <i> equals
|
|
<constant>MALLCTL_ARENAS_ALL</constant>. The proportion of unused
|
|
dirty/muzzy pages to be purged depends on the current time; see <link
|
|
linkend="opt.dirty_decay_time"><mallctl>opt.dirty_decay_time</mallctl></link>
|
|
and <link
|
|
linkend="opt.muzzy_decay_time"><mallctl>opt.muzy_decay_time</mallctl></link>
|
|
for details.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arena.i.purge">
|
|
<term>
|
|
<mallctl>arena.<i>.purge</mallctl>
|
|
(<type>void</type>)
|
|
<literal>--</literal>
|
|
</term>
|
|
<listitem><para>Purge all unused dirty pages for arena <i>, or for
|
|
all arenas if <i> equals <constant>MALLCTL_ARENAS_ALL</constant>.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arena.i.reset">
|
|
<term>
|
|
<mallctl>arena.<i>.reset</mallctl>
|
|
(<type>void</type>)
|
|
<literal>--</literal>
|
|
</term>
|
|
<listitem><para>Discard all of the arena's extant allocations. This
|
|
interface can only be used with arenas explicitly created via <link
|
|
linkend="arenas.create"><mallctl>arenas.create</mallctl></link>. None
|
|
of the arena's discarded/cached allocations may accessed afterward. As
|
|
part of this requirement, all thread caches which were used to
|
|
allocate/deallocate in conjunction with the arena must be flushed
|
|
beforehand.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arena.i.destroy">
|
|
<term>
|
|
<mallctl>arena.<i>.destroy</mallctl>
|
|
(<type>void</type>)
|
|
<literal>--</literal>
|
|
</term>
|
|
<listitem><para>Destroy the arena. Discard all of the arena's extant
|
|
allocations using the same mechanism as for <link
|
|
linkend="arena.i.reset"><mallctl>arena.<i>.reset</mallctl></link>
|
|
(with all the same constraints and side effects), merge the arena stats
|
|
into those accessible at arena index
|
|
<constant>MALLCTL_ARENAS_DESTROYED</constant>, and then completely
|
|
discard all metadata associated with the arena. Future calls to <link
|
|
linkend="arenas.create"><mallctl>arenas.create</mallctl></link> may
|
|
recycle the arena index. Destruction will fail if any threads are
|
|
currently associated with the arena as a result of calls to <link
|
|
linkend="thread.arena"><mallctl>thread.arena</mallctl></link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arena.i.dss">
|
|
<term>
|
|
<mallctl>arena.<i>.dss</mallctl>
|
|
(<type>const char *</type>)
|
|
<literal>rw</literal>
|
|
</term>
|
|
<listitem><para>Set the precedence of dss allocation as related to mmap
|
|
allocation for arena <i>, or for all arenas if <i> equals
|
|
<constant>MALLCTL_ARENAS_ALL</constant>. See <link
|
|
linkend="opt.dss"><mallctl>opt.dss</mallctl></link> for supported
|
|
settings.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arena.i.dirty_decay_time">
|
|
<term>
|
|
<mallctl>arena.<i>.dirty_decay_time</mallctl>
|
|
(<type>ssize_t</type>)
|
|
<literal>rw</literal>
|
|
</term>
|
|
<listitem><para>Current per-arena approximate time in seconds from the
|
|
creation of a set of unused dirty pages until an equivalent set of
|
|
unused dirty pages is purged and/or reused. Each time this interface is
|
|
set, all currently unused dirty pages are considered to have fully
|
|
decayed, which causes immediate purging of all unused dirty pages unless
|
|
the decay time is set to -1 (i.e. purging disabled). See <link
|
|
linkend="opt.dirty_decay_time"><mallctl>opt.dirty_decay_time</mallctl></link>
|
|
for additional information.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arena.i.muzzy_decay_time">
|
|
<term>
|
|
<mallctl>arena.<i>.muzzy_decay_time</mallctl>
|
|
(<type>ssize_t</type>)
|
|
<literal>rw</literal>
|
|
</term>
|
|
<listitem><para>Current per-arena approximate time in seconds from the
|
|
creation of a set of unused muzzy pages until an equivalent set of
|
|
unused muzzy pages is purged and/or reused. Each time this interface is
|
|
set, all currently unused muzzy pages are considered to have fully
|
|
decayed, which causes immediate purging of all unused muzzy pages unless
|
|
the decay time is set to -1 (i.e. purging disabled). See <link
|
|
linkend="opt.muzzy_decay_time"><mallctl>opt.muzzy_decay_time</mallctl></link>
|
|
for additional information.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arena.i.extent_hooks">
|
|
<term>
|
|
<mallctl>arena.<i>.extent_hooks</mallctl>
|
|
(<type>extent_hooks_t *</type>)
|
|
<literal>rw</literal>
|
|
</term>
|
|
<listitem><para>Get or set the extent management hook functions for
|
|
arena <i>. The functions must be capable of operating on all
|
|
extant extents associated with arena <i>, usually by passing
|
|
unknown extents to the replaced functions. In practice, it is feasible
|
|
to control allocation for arenas explicitly created via <link
|
|
linkend="arenas.create"><mallctl>arenas.create</mallctl></link> such
|
|
that all extents originate from an application-supplied extent allocator
|
|
(by specifying the custom extent hook functions during arena creation),
|
|
but the automatically created arenas will have already created extents
|
|
prior to the application having an opportunity to take over extent
|
|
allocation.</para>
|
|
|
|
<programlisting language="C"><![CDATA[
|
|
typedef extent_hooks_s extent_hooks_t;
|
|
struct extent_hooks_s {
|
|
extent_alloc_t *alloc;
|
|
extent_dalloc_t *dalloc;
|
|
extent_commit_t *commit;
|
|
extent_decommit_t *decommit;
|
|
extent_purge_t *purge_lazy;
|
|
extent_purge_t *purge_forced;
|
|
extent_split_t *split;
|
|
extent_merge_t *merge;
|
|
};]]></programlisting>
|
|
<para>The <type>extent_hooks_t</type> structure comprises function
|
|
pointers which are described individually below. jemalloc uses these
|
|
functions to manage extent lifetime, which starts off with allocation of
|
|
mapped committed memory, in the simplest case followed by deallocation.
|
|
However, there are performance and platform reasons to retain extents
|
|
for later reuse. Cleanup attempts cascade from deallocation to decommit
|
|
to forced purging to lazy purging, which gives the extent management
|
|
functions opportunities to reject the most permanent cleanup operations
|
|
in favor of less permanent (and often less costly) operations. All
|
|
operations except allocation can be universally opted out of by setting
|
|
the hook pointers to <constant>NULL</constant>, or selectively opted out
|
|
of by returning failure.</para>
|
|
|
|
<funcsynopsis><funcprototype>
|
|
<funcdef>typedef void *<function>(extent_alloc_t)</function></funcdef>
|
|
<paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef>
|
|
<paramdef>void *<parameter>new_addr</parameter></paramdef>
|
|
<paramdef>size_t <parameter>size</parameter></paramdef>
|
|
<paramdef>size_t <parameter>alignment</parameter></paramdef>
|
|
<paramdef>bool *<parameter>zero</parameter></paramdef>
|
|
<paramdef>bool *<parameter>commit</parameter></paramdef>
|
|
<paramdef>unsigned <parameter>arena_ind</parameter></paramdef>
|
|
</funcprototype></funcsynopsis>
|
|
<literallayout></literallayout>
|
|
<para>An extent allocation function conforms to the
|
|
<type>extent_alloc_t</type> type and upon success returns a pointer to
|
|
<parameter>size</parameter> bytes of mapped memory on behalf of arena
|
|
<parameter>arena_ind</parameter> such that the extent's base address is
|
|
a multiple of <parameter>alignment</parameter>, as well as setting
|
|
<parameter>*zero</parameter> to indicate whether the extent is zeroed
|
|
and <parameter>*commit</parameter> to indicate whether the extent is
|
|
committed. Upon error the function returns <constant>NULL</constant>
|
|
and leaves <parameter>*zero</parameter> and
|
|
<parameter>*commit</parameter> unmodified. The
|
|
<parameter>size</parameter> parameter is always a multiple of the page
|
|
size. The <parameter>alignment</parameter> parameter is always a power
|
|
of two at least as large as the page size. Zeroing is mandatory if
|
|
<parameter>*zero</parameter> is true upon function entry. Committing is
|
|
mandatory if <parameter>*commit</parameter> is true upon function entry.
|
|
If <parameter>new_addr</parameter> is not <constant>NULL</constant>, the
|
|
returned pointer must be <parameter>new_addr</parameter> on success or
|
|
<constant>NULL</constant> on error. Committed memory may be committed
|
|
in absolute terms as on a system that does not overcommit, or in
|
|
implicit terms as on a system that overcommits and satisfies physical
|
|
memory needs on demand via soft page faults. Note that replacing the
|
|
default extent allocation function makes the arena's <link
|
|
linkend="arena.i.dss"><mallctl>arena.<i>.dss</mallctl></link>
|
|
setting irrelevant.</para>
|
|
|
|
<funcsynopsis><funcprototype>
|
|
<funcdef>typedef bool <function>(extent_dalloc_t)</function></funcdef>
|
|
<paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef>
|
|
<paramdef>void *<parameter>addr</parameter></paramdef>
|
|
<paramdef>size_t <parameter>size</parameter></paramdef>
|
|
<paramdef>bool <parameter>committed</parameter></paramdef>
|
|
<paramdef>unsigned <parameter>arena_ind</parameter></paramdef>
|
|
</funcprototype></funcsynopsis>
|
|
<literallayout></literallayout>
|
|
<para>
|
|
An extent deallocation function conforms to the
|
|
<type>extent_dalloc_t</type> type and deallocates an extent at given
|
|
<parameter>addr</parameter> and <parameter>size</parameter> with
|
|
<parameter>committed</parameter>/decommited memory as indicated, on
|
|
behalf of arena <parameter>arena_ind</parameter>, returning false upon
|
|
success. If the function returns true, this indicates opt-out from
|
|
deallocation; the virtual memory mapping associated with the extent
|
|
remains mapped, in the same commit state, and available for future use,
|
|
in which case it will be automatically retained for later reuse.</para>
|
|
|
|
<funcsynopsis><funcprototype>
|
|
<funcdef>typedef bool <function>(extent_commit_t)</function></funcdef>
|
|
<paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef>
|
|
<paramdef>void *<parameter>addr</parameter></paramdef>
|
|
<paramdef>size_t <parameter>size</parameter></paramdef>
|
|
<paramdef>size_t <parameter>offset</parameter></paramdef>
|
|
<paramdef>size_t <parameter>length</parameter></paramdef>
|
|
<paramdef>unsigned <parameter>arena_ind</parameter></paramdef>
|
|
</funcprototype></funcsynopsis>
|
|
<literallayout></literallayout>
|
|
<para>An extent commit function conforms to the
|
|
<type>extent_commit_t</type> type and commits zeroed physical memory to
|
|
back pages within an extent at given <parameter>addr</parameter> and
|
|
<parameter>size</parameter> at <parameter>offset</parameter> bytes,
|
|
extending for <parameter>length</parameter> on behalf of arena
|
|
<parameter>arena_ind</parameter>, returning false upon success.
|
|
Committed memory may be committed in absolute terms as on a system that
|
|
does not overcommit, or in implicit terms as on a system that
|
|
overcommits and satisfies physical memory needs on demand via soft page
|
|
faults. If the function returns true, this indicates insufficient
|
|
physical memory to satisfy the request.</para>
|
|
|
|
<funcsynopsis><funcprototype>
|
|
<funcdef>typedef bool <function>(extent_decommit_t)</function></funcdef>
|
|
<paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef>
|
|
<paramdef>void *<parameter>addr</parameter></paramdef>
|
|
<paramdef>size_t <parameter>size</parameter></paramdef>
|
|
<paramdef>size_t <parameter>offset</parameter></paramdef>
|
|
<paramdef>size_t <parameter>length</parameter></paramdef>
|
|
<paramdef>unsigned <parameter>arena_ind</parameter></paramdef>
|
|
</funcprototype></funcsynopsis>
|
|
<literallayout></literallayout>
|
|
<para>An extent decommit function conforms to the
|
|
<type>extent_decommit_t</type> type and decommits any physical memory
|
|
that is backing pages within an extent at given
|
|
<parameter>addr</parameter> and <parameter>size</parameter> at
|
|
<parameter>offset</parameter> bytes, extending for
|
|
<parameter>length</parameter> on behalf of arena
|
|
<parameter>arena_ind</parameter>, returning false upon success, in which
|
|
case the pages will be committed via the extent commit function before
|
|
being reused. If the function returns true, this indicates opt-out from
|
|
decommit; the memory remains committed and available for future use, in
|
|
which case it will be automatically retained for later reuse.</para>
|
|
|
|
<funcsynopsis><funcprototype>
|
|
<funcdef>typedef bool <function>(extent_purge_t)</function></funcdef>
|
|
<paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef>
|
|
<paramdef>void *<parameter>addr</parameter></paramdef>
|
|
<paramdef>size_t <parameter>size</parameter></paramdef>
|
|
<paramdef>size_t <parameter>offset</parameter></paramdef>
|
|
<paramdef>size_t <parameter>length</parameter></paramdef>
|
|
<paramdef>unsigned <parameter>arena_ind</parameter></paramdef>
|
|
</funcprototype></funcsynopsis>
|
|
<literallayout></literallayout>
|
|
<para>An extent purge function conforms to the
|
|
<type>extent_purge_t</type> type and discards physical pages
|
|
within the virtual memory mapping associated with an extent at given
|
|
<parameter>addr</parameter> and <parameter>size</parameter> at
|
|
<parameter>offset</parameter> bytes, extending for
|
|
<parameter>length</parameter> on behalf of arena
|
|
<parameter>arena_ind</parameter>. A lazy extent purge function (e.g.
|
|
implemented via
|
|
<function>madvise(<parameter>...</parameter><parameter><constant>MADV_FREE</constant></parameter>)</function>)
|
|
can delay purging indefinitely and leave the pages within the purged
|
|
virtual memory range in an indeterminite state, whereas a forced extent
|
|
purge function immediately purges, and the pages within the virtual
|
|
memory range will be zero-filled the next time they are accessed. If
|
|
the function returns true, this indicates failure to purge.</para>
|
|
|
|
<funcsynopsis><funcprototype>
|
|
<funcdef>typedef bool <function>(extent_split_t)</function></funcdef>
|
|
<paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef>
|
|
<paramdef>void *<parameter>addr</parameter></paramdef>
|
|
<paramdef>size_t <parameter>size</parameter></paramdef>
|
|
<paramdef>size_t <parameter>size_a</parameter></paramdef>
|
|
<paramdef>size_t <parameter>size_b</parameter></paramdef>
|
|
<paramdef>bool <parameter>committed</parameter></paramdef>
|
|
<paramdef>unsigned <parameter>arena_ind</parameter></paramdef>
|
|
</funcprototype></funcsynopsis>
|
|
<literallayout></literallayout>
|
|
<para>An extent split function conforms to the
|
|
<type>extent_split_t</type> type and optionally splits an extent at
|
|
given <parameter>addr</parameter> and <parameter>size</parameter> into
|
|
two adjacent extents, the first of <parameter>size_a</parameter> bytes,
|
|
and the second of <parameter>size_b</parameter> bytes, operating on
|
|
<parameter>committed</parameter>/decommitted memory as indicated, on
|
|
behalf of arena <parameter>arena_ind</parameter>, returning false upon
|
|
success. If the function returns true, this indicates that the extent
|
|
remains unsplit and therefore should continue to be operated on as a
|
|
whole.</para>
|
|
|
|
<funcsynopsis><funcprototype>
|
|
<funcdef>typedef bool <function>(extent_merge_t)</function></funcdef>
|
|
<paramdef>extent_hooks_t *<parameter>extent_hooks</parameter></paramdef>
|
|
<paramdef>void *<parameter>addr_a</parameter></paramdef>
|
|
<paramdef>size_t <parameter>size_a</parameter></paramdef>
|
|
<paramdef>void *<parameter>addr_b</parameter></paramdef>
|
|
<paramdef>size_t <parameter>size_b</parameter></paramdef>
|
|
<paramdef>bool <parameter>committed</parameter></paramdef>
|
|
<paramdef>unsigned <parameter>arena_ind</parameter></paramdef>
|
|
</funcprototype></funcsynopsis>
|
|
<literallayout></literallayout>
|
|
<para>An extent merge function conforms to the
|
|
<type>extent_merge_t</type> type and optionally merges adjacent extents,
|
|
at given <parameter>addr_a</parameter> and <parameter>size_a</parameter>
|
|
with given <parameter>addr_b</parameter> and
|
|
<parameter>size_b</parameter> into one contiguous extent, operating on
|
|
<parameter>committed</parameter>/decommitted memory as indicated, on
|
|
behalf of arena <parameter>arena_ind</parameter>, returning false upon
|
|
success. If the function returns true, this indicates that the extents
|
|
remain distinct mappings and therefore should continue to be operated on
|
|
independently.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.narenas">
|
|
<term>
|
|
<mallctl>arenas.narenas</mallctl>
|
|
(<type>unsigned</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Current limit on number of arenas.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.dirty_decay_time">
|
|
<term>
|
|
<mallctl>arenas.dirty_decay_time</mallctl>
|
|
(<type>ssize_t</type>)
|
|
<literal>rw</literal>
|
|
</term>
|
|
<listitem><para>Current default per-arena approximate time in seconds
|
|
from the creation of a set of unused dirty pages until an equivalent set
|
|
of unused dirty pages is purged and/or reused, used to initialize <link
|
|
linkend="arena.i.dirty_decay_time"><mallctl>arena.<i>.dirty_decay_time</mallctl></link>
|
|
during arena creation. See <link
|
|
linkend="opt.dirty_decay_time"><mallctl>opt.dirty_decay_time</mallctl></link>
|
|
for additional information.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.muzzy_decay_time">
|
|
<term>
|
|
<mallctl>arenas.muzzy_decay_time</mallctl>
|
|
(<type>ssize_t</type>)
|
|
<literal>rw</literal>
|
|
</term>
|
|
<listitem><para>Current default per-arena approximate time in seconds
|
|
from the creation of a set of unused muzzy pages until an equivalent set
|
|
of unused muzzy pages is purged and/or reused, used to initialize <link
|
|
linkend="arena.i.muzzy_decay_time"><mallctl>arena.<i>.muzzy_decay_time</mallctl></link>
|
|
during arena creation. See <link
|
|
linkend="opt.muzzy_decay_time"><mallctl>opt.muzzy_decay_time</mallctl></link>
|
|
for additional information.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.quantum">
|
|
<term>
|
|
<mallctl>arenas.quantum</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Quantum size.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.page">
|
|
<term>
|
|
<mallctl>arenas.page</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Page size.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.tcache_max">
|
|
<term>
|
|
<mallctl>arenas.tcache_max</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Maximum thread-cached size class.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.nbins">
|
|
<term>
|
|
<mallctl>arenas.nbins</mallctl>
|
|
(<type>unsigned</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Number of bin size classes.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.nhbins">
|
|
<term>
|
|
<mallctl>arenas.nhbins</mallctl>
|
|
(<type>unsigned</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Total number of thread cache bin size
|
|
classes.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.bin.i.size">
|
|
<term>
|
|
<mallctl>arenas.bin.<i>.size</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Maximum size supported by size class.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.bin.i.nregs">
|
|
<term>
|
|
<mallctl>arenas.bin.<i>.nregs</mallctl>
|
|
(<type>uint32_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Number of regions per slab.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.bin.i.slab_size">
|
|
<term>
|
|
<mallctl>arenas.bin.<i>.slab_size</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Number of bytes per slab.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.nlextents">
|
|
<term>
|
|
<mallctl>arenas.nlextents</mallctl>
|
|
(<type>unsigned</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Total number of large size classes.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.lextent.i.size">
|
|
<term>
|
|
<mallctl>arenas.lextent.<i>.size</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Maximum size supported by this large size
|
|
class.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="arenas.create">
|
|
<term>
|
|
<mallctl>arenas.create</mallctl>
|
|
(<type>unsigned</type>, <type>extent_hooks_t *</type>)
|
|
<literal>rw</literal>
|
|
</term>
|
|
<listitem><para>Explicitly create a new arena outside the range of
|
|
automatically managed arenas, with optionally specified extent hooks,
|
|
and return the new arena index.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="prof.thread_active_init">
|
|
<term>
|
|
<mallctl>prof.thread_active_init</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>rw</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Control the initial setting for <link
|
|
linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link>
|
|
in newly created threads. See the <link
|
|
linkend="opt.prof_thread_active_init"><mallctl>opt.prof_thread_active_init</mallctl></link>
|
|
option for additional information.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="prof.active">
|
|
<term>
|
|
<mallctl>prof.active</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>rw</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Control whether sampling is currently active. See the
|
|
<link
|
|
linkend="opt.prof_active"><mallctl>opt.prof_active</mallctl></link>
|
|
option for additional information, as well as the interrelated <link
|
|
linkend="thread.prof.active"><mallctl>thread.prof.active</mallctl></link>
|
|
mallctl.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="prof.dump">
|
|
<term>
|
|
<mallctl>prof.dump</mallctl>
|
|
(<type>const char *</type>)
|
|
<literal>-w</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Dump a memory profile to the specified file, or if NULL
|
|
is specified, to a file according to the pattern
|
|
<filename><prefix>.<pid>.<seq>.m<mseq>.heap</filename>,
|
|
where <literal><prefix></literal> is controlled by the
|
|
<link
|
|
linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link>
|
|
option.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="prof.gdump">
|
|
<term>
|
|
<mallctl>prof.gdump</mallctl>
|
|
(<type>bool</type>)
|
|
<literal>rw</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>When enabled, trigger a memory profile dump every time
|
|
the total virtual memory exceeds the previous maximum. Profiles are
|
|
dumped to files named according to the pattern
|
|
<filename><prefix>.<pid>.<seq>.u<useq>.heap</filename>,
|
|
where <literal><prefix></literal> is controlled by the <link
|
|
linkend="opt.prof_prefix"><mallctl>opt.prof_prefix</mallctl></link>
|
|
option.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="prof.reset">
|
|
<term>
|
|
<mallctl>prof.reset</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>-w</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Reset all memory profile statistics, and optionally
|
|
update the sample rate (see <link
|
|
linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link>
|
|
and <link
|
|
linkend="prof.lg_sample"><mallctl>prof.lg_sample</mallctl></link>).
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="prof.lg_sample">
|
|
<term>
|
|
<mallctl>prof.lg_sample</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Get the current sample rate (see <link
|
|
linkend="opt.lg_prof_sample"><mallctl>opt.lg_prof_sample</mallctl></link>).
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="prof.interval">
|
|
<term>
|
|
<mallctl>prof.interval</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-prof</option>]
|
|
</term>
|
|
<listitem><para>Average number of bytes allocated between
|
|
interval-based profile dumps. See the
|
|
<link
|
|
linkend="opt.lg_prof_interval"><mallctl>opt.lg_prof_interval</mallctl></link>
|
|
option for additional information.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.allocated">
|
|
<term>
|
|
<mallctl>stats.allocated</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Total number of bytes allocated by the
|
|
application.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.active">
|
|
<term>
|
|
<mallctl>stats.active</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Total number of bytes in active pages allocated by the
|
|
application. This is a multiple of the page size, and greater than or
|
|
equal to <link
|
|
linkend="stats.allocated"><mallctl>stats.allocated</mallctl></link>.
|
|
This does not include <link linkend="stats.arenas.i.pdirty">
|
|
<mallctl>stats.arenas.<i>.pdirty</mallctl></link>,
|
|
<link linkend="stats.arenas.i.pmuzzy">
|
|
<mallctl>stats.arenas.<i>.pmuzzy</mallctl></link>, nor pages
|
|
entirely devoted to allocator metadata.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.metadata">
|
|
<term>
|
|
<mallctl>stats.metadata</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Total number of bytes dedicated to metadata, which
|
|
comprise base allocations used for bootstrap-sensitive allocator
|
|
metadata structures (see <link
|
|
linkend="stats.arenas.i.base"><mallctl>stats.arenas.<i>.base</mallctl></link>)
|
|
and internal allocations (see <link
|
|
linkend="stats.arenas.i.internal"><mallctl>stats.arenas.<i>.internal</mallctl></link>).</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.resident">
|
|
<term>
|
|
<mallctl>stats.resident</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Maximum number of bytes in physically resident data
|
|
pages mapped by the allocator, comprising all pages dedicated to
|
|
allocator metadata, pages backing active allocations, and unused dirty
|
|
pages. This is a maximum rather than precise because pages may not
|
|
actually be physically resident if they correspond to demand-zeroed
|
|
virtual memory that has not yet been touched. This is a multiple of the
|
|
page size, and is larger than <link
|
|
linkend="stats.active"><mallctl>stats.active</mallctl></link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.mapped">
|
|
<term>
|
|
<mallctl>stats.mapped</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Total number of bytes in active extents mapped by the
|
|
allocator. This is larger than <link
|
|
linkend="stats.active"><mallctl>stats.active</mallctl></link>. This
|
|
does not include inactive extents, even those that contain unused dirty
|
|
pages, which means that there is no strict ordering between this and
|
|
<link
|
|
linkend="stats.resident"><mallctl>stats.resident</mallctl></link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.retained">
|
|
<term>
|
|
<mallctl>stats.retained</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Total number of bytes in virtual memory mappings that
|
|
were retained rather than being returned to the operating system via
|
|
e.g. <citerefentry><refentrytitle>munmap</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry>. Retained virtual memory is
|
|
typically untouched, decommitted, or purged, so it has no strongly
|
|
associated physical memory (see <link
|
|
linkend="arena.i.extent_hooks">extent hooks</link> for details).
|
|
Retained memory is excluded from mapped memory statistics, e.g. <link
|
|
linkend="stats.mapped"><mallctl>stats.mapped</mallctl></link>.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.mutexes.ctl">
|
|
<term>
|
|
<mallctl>stats.mutexes.ctl.{counter};</mallctl>
|
|
(<type>counter specific type</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on <varname>ctl</varname> mutex (global
|
|
scope; mallctl related). <mallctl>{counter}</mallctl> is one of the
|
|
counters below:</para>
|
|
<varlistentry id="mutex_counters">
|
|
<listitem><para><varname>num_ops</varname> (<type>uint64_t</type>):
|
|
Total number of lock acquisition operations on this mutex.</para>
|
|
|
|
<para><varname>num_spin_acq</varname> (<type>uint64_t</type>): Number
|
|
of times the mutex was spin-acquired. When the mutex is currently
|
|
locked and cannot be acquired immediately, a short period of
|
|
spin-retry within jemalloc will be performed. Acquired through spin
|
|
generally means the contention was lightweight and not causing context
|
|
switches.</para>
|
|
|
|
<para><varname>num_wait</varname> (<type>uint64_t</type>): Number of
|
|
times the mutex was wait-acquired, which means the mutex contention
|
|
was not solved by spin-retry, and blocking operation was likely
|
|
involved in order to acquire the mutex. This event generally implies
|
|
higher cost / longer delay, and should be investigated if it happens
|
|
often.</para>
|
|
|
|
<para><varname>max_wait_time</varname> (<type>uint64_t</type>):
|
|
Maximum length of time in nanoseconds spent on a single wait-acquired
|
|
lock operation. Note that to avoid profiling overhead on the common
|
|
path, this does not consider spin-acquired cases.</para>
|
|
|
|
<para><varname>total_wait_time</varname> (<type>uint64_t</type>):
|
|
Cumulative time in nanoseconds spent on wait-acquired lock operations.
|
|
Similarly, spin-acquired cases are not considered.</para>
|
|
|
|
<para><varname>max_num_thds</varname> (<type>uint32_t</type>): Maximum
|
|
number of threads waiting on this mutex simultaneously. Similarly,
|
|
spin-acquired cases are not considered.</para>
|
|
|
|
<para><varname>num_owner_switch</varname> (<type>uint64_t</type>):
|
|
Number of times the current mutex owner is different from the previous
|
|
one. This event does not generally imply an issue; rather it is an
|
|
indicator of how often the protected data are accessed by different
|
|
threads.
|
|
</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
</listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.mutexes.prof">
|
|
<term>
|
|
<mallctl>stats.mutexes.prof.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on <varname>prof</varname> mutex (global
|
|
scope; profiling related). <mallctl>{counter}</mallctl> is one of the
|
|
counters in <link linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.mutexes.reset">
|
|
<term>
|
|
<mallctl>stats.mutexes.reset</mallctl>
|
|
(<type>void</type>) <literal>--</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Reset all mutex profile statistics, including global
|
|
mutexes, arena mutexes and bin mutexes.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.dss">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.dss</mallctl>
|
|
(<type>const char *</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>dss (<citerefentry><refentrytitle>sbrk</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry>) allocation precedence as
|
|
related to <citerefentry><refentrytitle>mmap</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry> allocation. See <link
|
|
linkend="opt.dss"><mallctl>opt.dss</mallctl></link> for details.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.dirty_decay_time">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.dirty_decay_time</mallctl>
|
|
(<type>ssize_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Approximate time in seconds from the creation of a set
|
|
of unused dirty pages until an equivalent set of unused dirty pages is
|
|
purged and/or reused. See <link
|
|
linkend="opt.dirty_decay_time"><mallctl>opt.dirty_decay_time</mallctl></link>
|
|
for details.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.muzzy_decay_time">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.muzzy_decay_time</mallctl>
|
|
(<type>ssize_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Approximate time in seconds from the creation of a set
|
|
of unused muzzy pages until an equivalent set of unused muzzy pages is
|
|
purged and/or reused. See <link
|
|
linkend="opt.muzzy_decay_time"><mallctl>opt.muzzy_decay_time</mallctl></link>
|
|
for details.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.nthreads">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.nthreads</mallctl>
|
|
(<type>unsigned</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Number of threads currently assigned to
|
|
arena.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.pactive">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.pactive</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Number of pages in active extents.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.pdirty">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.pdirty</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Number of pages within unused extents that are
|
|
potentially dirty, and for which <function>madvise()</function> or
|
|
similar has not been called. See <link
|
|
linkend="opt.dirty_decay_time"><mallctl>opt.dirty_decay_time</mallctl></link>
|
|
for a description of dirty pages.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.pmuzzy">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.pmuzzy</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
</term>
|
|
<listitem><para>Number of pages within unused extents that are muzzy.
|
|
See <link
|
|
linkend="opt.muzzy_decay_time"><mallctl>opt.muzzy_decay_time</mallctl></link>
|
|
for a description of muzzy pages.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.mapped">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.mapped</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of mapped bytes.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.retained">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.retained</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of retained bytes. See <link
|
|
linkend="stats.retained"><mallctl>stats.retained</mallctl></link> for
|
|
details.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.base">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.base</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>
|
|
Number of bytes dedicated to bootstrap-sensitive allocator metadata
|
|
structures.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.internal">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.internal</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of bytes dedicated to internal allocations.
|
|
Internal allocations differ from application-originated allocations in
|
|
that they are for internal use, and that they are omitted from heap
|
|
profiles.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.resident">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.resident</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Maximum number of bytes in physically resident data
|
|
pages mapped by the arena, comprising all pages dedicated to allocator
|
|
metadata, pages backing active allocations, and unused dirty pages.
|
|
This is a maximum rather than precise because pages may not actually be
|
|
physically resident if they correspond to demand-zeroed virtual memory
|
|
that has not yet been touched. This is a multiple of the page
|
|
size.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.dirty_npurge">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.dirty_npurge</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of dirty page purge sweeps performed.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.dirty_nmadvise">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.dirty_nmadvise</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of <function>madvise()</function> or similar
|
|
calls made to purge dirty pages.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.dirty_purged">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.dirty_purged</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of dirty pages purged.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.muzzy_npurge">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.muzzy_npurge</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of muzzy page purge sweeps performed.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.muzzy_nmadvise">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.muzzy_nmadvise</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of <function>madvise()</function> or similar
|
|
calls made to purge muzzy pages.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.muzzy_purged">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.muzzy_purged</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of muzzy pages purged.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.small.allocated">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.small.allocated</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of bytes currently allocated by small objects.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.small.nmalloc">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.small.nmalloc</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of allocation requests served by
|
|
small bins.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.small.ndalloc">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.small.ndalloc</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of small objects returned to bins.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.small.nrequests">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.small.nrequests</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of small allocation requests.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.large.allocated">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.large.allocated</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Number of bytes currently allocated by large objects.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.large.nmalloc">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.large.nmalloc</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of large allocation requests served
|
|
directly by the arena.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.large.ndalloc">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.large.ndalloc</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of large deallocation requests served
|
|
directly by the arena.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.large.nrequests">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.large.nrequests</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of large allocation requests.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.bins.j.nmalloc">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.bins.<j>.nmalloc</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of allocations served by bin.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.bins.j.ndalloc">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.bins.<j>.ndalloc</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of allocations returned to bin.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.bins.j.nrequests">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.bins.<j>.nrequests</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of allocation
|
|
requests.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.bins.j.curregs">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.bins.<j>.curregs</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Current number of regions for this size
|
|
class.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.bins.j.nfills">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.bins.<j>.nfills</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option> <option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of tcache fills.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.bins.j.nflushes">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.bins.<j>.nflushes</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option> <option>--enable-tcache</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of tcache flushes.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.bins.j.nslabs">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.bins.<j>.nslabs</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of slabs created.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.bins.j.nreslabs">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.bins.<j>.nreslabs</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of times the current slab from which
|
|
to allocate changed.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.bins.j.curslabs">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.bins.<j>.curslabs</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Current number of slabs.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.bins.mutex">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.bins.<j>.mutex.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on
|
|
<varname>arena.<i>.bins.<j></varname> mutex (arena bin
|
|
scope; bin operation related). <mallctl>{counter}</mallctl> is one of
|
|
the counters in <link linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.lextents.j.nmalloc">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.lextents.<j>.nmalloc</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of allocation requests for this size
|
|
class served directly by the arena.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.lextents.j.ndalloc">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.lextents.<j>.ndalloc</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of deallocation requests for this
|
|
size class served directly by the arena.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.lextents.j.nrequests">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.lextents.<j>.nrequests</mallctl>
|
|
(<type>uint64_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Cumulative number of allocation requests for this size
|
|
class.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.lextents.j.curlextents">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.lextents.<j>.curlextents</mallctl>
|
|
(<type>size_t</type>)
|
|
<literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Current number of large allocations for this size class.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.mutexes.large">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.mutexes.large.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on <varname>arena.<i>.large</varname>
|
|
mutex (arena scope; large allocation related).
|
|
<mallctl>{counter}</mallctl> is one of the counters in <link
|
|
linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.mutexes.extent_freelist">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.mutexes.extent_freelist.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on <varname>arena.<i>.extent_freelist
|
|
</varname> mutex (arena scope; extent freelist related).
|
|
<mallctl>{counter}</mallctl> is one of the counters in <link
|
|
linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.mutexes.extents_dirty">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.mutexes.extents_dirty.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on <varname>arena.<i>.extents_dirty
|
|
</varname> mutex (arena scope; dirty extents related).
|
|
<mallctl>{counter}</mallctl> is one of the counters in <link
|
|
linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.mutexes.extents_muzzy">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.mutexes.extents_muzzy.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on <varname>arena.<i>.extents_muzzy
|
|
</varname> mutex (arena scope; muzzy extents related).
|
|
<mallctl>{counter}</mallctl> is one of the counters in <link
|
|
linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.mutexes.extents_retained">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.mutexes.extents_retained.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on <varname>arena.<i>.extents_retained
|
|
</varname> mutex (arena scope; retained extents related).
|
|
<mallctl>{counter}</mallctl> is one of the counters in <link
|
|
linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.mutexes.decay_dirty">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.mutexes.decay_dirty.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on <varname>arena.<i>.decay_dirty
|
|
</varname> mutex (arena scope; decay for dirty pages related).
|
|
<mallctl>{counter}</mallctl> is one of the counters in <link
|
|
linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.mutexes.decay_muzzy">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.mutexes.decay_muzzy.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on <varname>arena.<i>.decay_muzzy
|
|
</varname> mutex (arena scope; decay for muzzy pages related).
|
|
<mallctl>{counter}</mallctl> is one of the counters in <link
|
|
linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.mutexes.base">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.mutexes.base.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on <varname>arena.<i>.base</varname>
|
|
mutex (arena scope; base allocator related).
|
|
<mallctl>{counter}</mallctl> is one of the counters in <link
|
|
linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
<varlistentry id="stats.arenas.i.mutexes.tcache_list">
|
|
<term>
|
|
<mallctl>stats.arenas.<i>.mutexes.tcache_list.{counter}</mallctl>
|
|
(<type>counter specific type</type>) <literal>r-</literal>
|
|
[<option>--enable-stats</option>]
|
|
</term>
|
|
<listitem><para>Statistics on
|
|
<varname>arena.<i>.tcache_list</varname> mutex (arena scope;
|
|
tcache to arena association related). This mutex is expected to be
|
|
accessed less often. <mallctl>{counter}</mallctl> is one of the
|
|
counters in <link linkend="mutex_counters">mutex profiling
|
|
counters</link>.</para></listitem>
|
|
</varlistentry>
|
|
|
|
</variablelist>
|
|
</refsect1>
|
|
<refsect1 id="heap_profile_format">
|
|
<title>HEAP PROFILE FORMAT</title>
|
|
<para>Although the heap profiling functionality was originally designed to
|
|
be compatible with the
|
|
<command>pprof</command> command that is developed as part of the <ulink
|
|
url="http://code.google.com/p/gperftools/">gperftools
|
|
package</ulink>, the addition of per thread heap profiling functionality
|
|
required a different heap profile format. The <command>jeprof</command>
|
|
command is derived from <command>pprof</command>, with enhancements to
|
|
support the heap profile format described here.</para>
|
|
|
|
<para>In the following hypothetical heap profile, <constant>[...]</constant>
|
|
indicates elision for the sake of compactness. <programlisting><![CDATA[
|
|
heap_v2/524288
|
|
t*: 28106: 56637512 [0: 0]
|
|
[...]
|
|
t3: 352: 16777344 [0: 0]
|
|
[...]
|
|
t99: 17754: 29341640 [0: 0]
|
|
[...]
|
|
@ 0x5f86da8 0x5f5a1dc [...] 0x29e4d4e 0xa200316 0xabb2988 [...]
|
|
t*: 13: 6688 [0: 0]
|
|
t3: 12: 6496 [0: ]
|
|
t99: 1: 192 [0: 0]
|
|
[...]
|
|
|
|
MAPPED_LIBRARIES:
|
|
[...]]]></programlisting> The following matches the above heap profile, but most
|
|
tokens are replaced with <constant><description></constant> to indicate
|
|
descriptions of the corresponding fields. <programlisting><![CDATA[
|
|
<heap_profile_format_version>/<mean_sample_interval>
|
|
<aggregate>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>]
|
|
[...]
|
|
<thread_3_aggregate>: <curobjs>: <curbytes>[<cumobjs>: <cumbytes>]
|
|
[...]
|
|
<thread_99_aggregate>: <curobjs>: <curbytes>[<cumobjs>: <cumbytes>]
|
|
[...]
|
|
@ <top_frame> <frame> [...] <frame> <frame> <frame> [...]
|
|
<backtrace_aggregate>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>]
|
|
<backtrace_thread_3>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>]
|
|
<backtrace_thread_99>: <curobjs>: <curbytes> [<cumobjs>: <cumbytes>]
|
|
[...]
|
|
|
|
MAPPED_LIBRARIES:
|
|
</proc/<pid>/maps>]]></programlisting></para>
|
|
</refsect1>
|
|
|
|
<refsect1 id="debugging_malloc_problems">
|
|
<title>DEBUGGING MALLOC PROBLEMS</title>
|
|
<para>When debugging, it is a good idea to configure/build jemalloc with
|
|
the <option>--enable-debug</option> and <option>--enable-fill</option>
|
|
options, and recompile the program with suitable options and symbols for
|
|
debugger support. When so configured, jemalloc incorporates a wide variety
|
|
of run-time assertions that catch application errors such as double-free,
|
|
write-after-free, etc.</para>
|
|
|
|
<para>Programs often accidentally depend on <quote>uninitialized</quote>
|
|
memory actually being filled with zero bytes. Junk filling
|
|
(see the <link linkend="opt.junk"><mallctl>opt.junk</mallctl></link>
|
|
option) tends to expose such bugs in the form of obviously incorrect
|
|
results and/or coredumps. Conversely, zero
|
|
filling (see the <link
|
|
linkend="opt.zero"><mallctl>opt.zero</mallctl></link> option) eliminates
|
|
the symptoms of such bugs. Between these two options, it is usually
|
|
possible to quickly detect, diagnose, and eliminate such bugs.</para>
|
|
|
|
<para>This implementation does not provide much detail about the problems
|
|
it detects, because the performance impact for storing such information
|
|
would be prohibitive.</para>
|
|
</refsect1>
|
|
<refsect1 id="diagnostic_messages">
|
|
<title>DIAGNOSTIC MESSAGES</title>
|
|
<para>If any of the memory allocation/deallocation functions detect an
|
|
error or warning condition, a message will be printed to file descriptor
|
|
<constant>STDERR_FILENO</constant>. Errors will result in the process
|
|
dumping core. If the <link
|
|
linkend="opt.abort"><mallctl>opt.abort</mallctl></link> option is set, most
|
|
warnings are treated as errors.</para>
|
|
|
|
<para>The <varname>malloc_message</varname> variable allows the programmer
|
|
to override the function which emits the text strings forming the errors
|
|
and warnings if for some reason the <constant>STDERR_FILENO</constant> file
|
|
descriptor is not suitable for this.
|
|
<function>malloc_message()</function> takes the
|
|
<parameter>cbopaque</parameter> pointer argument that is
|
|
<constant>NULL</constant> unless overridden by the arguments in a call to
|
|
<function>malloc_stats_print()</function>, followed by a string
|
|
pointer. Please note that doing anything which tries to allocate memory in
|
|
this function is likely to result in a crash or deadlock.</para>
|
|
|
|
<para>All messages are prefixed by
|
|
<quote><computeroutput><jemalloc>: </computeroutput></quote>.</para>
|
|
</refsect1>
|
|
<refsect1 id="return_values">
|
|
<title>RETURN VALUES</title>
|
|
<refsect2>
|
|
<title>Standard API</title>
|
|
<para>The <function>malloc()</function> and
|
|
<function>calloc()</function> functions return a pointer to the
|
|
allocated memory if successful; otherwise a <constant>NULL</constant>
|
|
pointer is returned and <varname>errno</varname> is set to
|
|
<errorname>ENOMEM</errorname>.</para>
|
|
|
|
<para>The <function>posix_memalign()</function> function
|
|
returns the value 0 if successful; otherwise it returns an error value.
|
|
The <function>posix_memalign()</function> function will fail
|
|
if:
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><errorname>EINVAL</errorname></term>
|
|
|
|
<listitem><para>The <parameter>alignment</parameter> parameter is
|
|
not a power of 2 at least as large as
|
|
<code language="C">sizeof(<type>void *</type>)</code>.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><errorname>ENOMEM</errorname></term>
|
|
|
|
<listitem><para>Memory allocation error.</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</para>
|
|
|
|
<para>The <function>aligned_alloc()</function> function returns
|
|
a pointer to the allocated memory if successful; otherwise a
|
|
<constant>NULL</constant> pointer is returned and
|
|
<varname>errno</varname> is set. The
|
|
<function>aligned_alloc()</function> function will fail if:
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><errorname>EINVAL</errorname></term>
|
|
|
|
<listitem><para>The <parameter>alignment</parameter> parameter is
|
|
not a power of 2.
|
|
</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><errorname>ENOMEM</errorname></term>
|
|
|
|
<listitem><para>Memory allocation error.</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</para>
|
|
|
|
<para>The <function>realloc()</function> function returns a
|
|
pointer, possibly identical to <parameter>ptr</parameter>, to the
|
|
allocated memory if successful; otherwise a <constant>NULL</constant>
|
|
pointer is returned, and <varname>errno</varname> is set to
|
|
<errorname>ENOMEM</errorname> if the error was the result of an
|
|
allocation failure. The <function>realloc()</function>
|
|
function always leaves the original buffer intact when an error occurs.
|
|
</para>
|
|
|
|
<para>The <function>free()</function> function returns no
|
|
value.</para>
|
|
</refsect2>
|
|
<refsect2>
|
|
<title>Non-standard API</title>
|
|
<para>The <function>mallocx()</function> and
|
|
<function>rallocx()</function> functions return a pointer to
|
|
the allocated memory if successful; otherwise a <constant>NULL</constant>
|
|
pointer is returned to indicate insufficient contiguous memory was
|
|
available to service the allocation request. </para>
|
|
|
|
<para>The <function>xallocx()</function> function returns the
|
|
real size of the resulting resized allocation pointed to by
|
|
<parameter>ptr</parameter>, which is a value less than
|
|
<parameter>size</parameter> if the allocation could not be adequately
|
|
grown in place. </para>
|
|
|
|
<para>The <function>sallocx()</function> function returns the
|
|
real size of the allocation pointed to by <parameter>ptr</parameter>.
|
|
</para>
|
|
|
|
<para>The <function>nallocx()</function> returns the real size
|
|
that would result from a successful equivalent
|
|
<function>mallocx()</function> function call, or zero if
|
|
insufficient memory is available to perform the size computation. </para>
|
|
|
|
<para>The <function>mallctl()</function>,
|
|
<function>mallctlnametomib()</function>, and
|
|
<function>mallctlbymib()</function> functions return 0 on
|
|
success; otherwise they return an error value. The functions will fail
|
|
if:
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><errorname>EINVAL</errorname></term>
|
|
|
|
<listitem><para><parameter>newp</parameter> is not
|
|
<constant>NULL</constant>, and <parameter>newlen</parameter> is too
|
|
large or too small. Alternatively, <parameter>*oldlenp</parameter>
|
|
is too large or too small; in this case as much data as possible
|
|
are read despite the error.</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><errorname>ENOENT</errorname></term>
|
|
|
|
<listitem><para><parameter>name</parameter> or
|
|
<parameter>mib</parameter> specifies an unknown/invalid
|
|
value.</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><errorname>EPERM</errorname></term>
|
|
|
|
<listitem><para>Attempt to read or write void value, or attempt to
|
|
write read-only value.</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><errorname>EAGAIN</errorname></term>
|
|
|
|
<listitem><para>A memory allocation failure
|
|
occurred.</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term><errorname>EFAULT</errorname></term>
|
|
|
|
<listitem><para>An interface with side effects failed in some way
|
|
not directly related to <function>mallctl*()</function>
|
|
read/write processing.</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</para>
|
|
|
|
<para>The <function>malloc_usable_size()</function> function
|
|
returns the usable size of the allocation pointed to by
|
|
<parameter>ptr</parameter>. </para>
|
|
</refsect2>
|
|
</refsect1>
|
|
<refsect1 id="environment">
|
|
<title>ENVIRONMENT</title>
|
|
<para>The following environment variable affects the execution of the
|
|
allocation functions:
|
|
<variablelist>
|
|
<varlistentry>
|
|
<term><envar>MALLOC_CONF</envar></term>
|
|
|
|
<listitem><para>If the environment variable
|
|
<envar>MALLOC_CONF</envar> is set, the characters it contains
|
|
will be interpreted as options.</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</para>
|
|
</refsect1>
|
|
<refsect1 id="examples">
|
|
<title>EXAMPLES</title>
|
|
<para>To dump core whenever a problem occurs:
|
|
<screen>ln -s 'abort:true' /etc/malloc.conf</screen>
|
|
</para>
|
|
<para>To specify in the source that only one arena should be automatically
|
|
created:
|
|
<programlisting language="C"><![CDATA[
|
|
malloc_conf = "narenas:1";]]></programlisting></para>
|
|
</refsect1>
|
|
<refsect1 id="see_also">
|
|
<title>SEE ALSO</title>
|
|
<para><citerefentry><refentrytitle>madvise</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>mmap</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>sbrk</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>utrace</refentrytitle>
|
|
<manvolnum>2</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>alloca</refentrytitle>
|
|
<manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>atexit</refentrytitle>
|
|
<manvolnum>3</manvolnum></citerefentry>,
|
|
<citerefentry><refentrytitle>getpagesize</refentrytitle>
|
|
<manvolnum>3</manvolnum></citerefentry></para>
|
|
</refsect1>
|
|
<refsect1 id="standards">
|
|
<title>STANDARDS</title>
|
|
<para>The <function>malloc()</function>,
|
|
<function>calloc()</function>,
|
|
<function>realloc()</function>, and
|
|
<function>free()</function> functions conform to ISO/IEC
|
|
9899:1990 (<quote>ISO C90</quote>).</para>
|
|
|
|
<para>The <function>posix_memalign()</function> function conforms
|
|
to IEEE Std 1003.1-2001 (<quote>POSIX.1</quote>).</para>
|
|
</refsect1>
|
|
</refentry>
|