Add check for madvise(2) to configure.ac.

Some platforms, such as Google's Portable Native Client, use Newlib and
thus lack access to madvise(2).  In those instances, pages_purge() is
transformed into a no-op.
This commit is contained in:
Richard Diamond 2014-06-03 02:39:18 -05:00 committed by Jason Evans
parent 70807bc54b
commit 994fad9bda
3 changed files with 24 additions and 2 deletions

View File

@ -1191,6 +1191,20 @@ if test "x${je_cv_osatomic}" = "xyes" ; then
AC_DEFINE([JEMALLOC_OSATOMIC], [ ]) AC_DEFINE([JEMALLOC_OSATOMIC], [ ])
fi fi
dnl ============================================================================
dnl Check for madvise(2).
JE_COMPILABLE([madvise(2)], [
#include <sys/mman.h>
], [
{
madvise((void *)0, 0, 0);
}
], [je_cv_madvise])
if test "x${je_cv_madvise}" = "xyes" ; then
AC_DEFINE([JEMALLOC_HAVE_MADVISE], [ ])
fi
dnl ============================================================================ dnl ============================================================================
dnl Check whether __sync_{add,sub}_and_fetch() are available despite dnl Check whether __sync_{add,sub}_and_fetch() are available despite
dnl __GCC_HAVE_SYNC_COMPARE_AND_SWAP_n macros being undefined. dnl __GCC_HAVE_SYNC_COMPARE_AND_SWAP_n macros being undefined.

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@ -52,6 +52,11 @@
*/ */
#undef JEMALLOC_HAVE_BUILTIN_CLZ #undef JEMALLOC_HAVE_BUILTIN_CLZ
/*
* Defined if madvise(2) is available.
*/
#undef JEMALLOC_HAVE_MADVISE
/* /*
* Defined if OSSpin*() functions are available, as provided by Darwin, and * Defined if OSSpin*() functions are available, as provided by Darwin, and
* documented in the spinlock(3) manual page. * documented in the spinlock(3) manual page.

View File

@ -121,7 +121,7 @@ pages_purge(void *addr, size_t length)
#ifdef _WIN32 #ifdef _WIN32
VirtualAlloc(addr, length, MEM_RESET, PAGE_READWRITE); VirtualAlloc(addr, length, MEM_RESET, PAGE_READWRITE);
unzeroed = true; unzeroed = true;
#else #elif defined(JEMALLOC_HAVE_MADVISE)
# ifdef JEMALLOC_PURGE_MADVISE_DONTNEED # ifdef JEMALLOC_PURGE_MADVISE_DONTNEED
# define JEMALLOC_MADV_PURGE MADV_DONTNEED # define JEMALLOC_MADV_PURGE MADV_DONTNEED
# define JEMALLOC_MADV_ZEROS true # define JEMALLOC_MADV_ZEROS true
@ -129,12 +129,15 @@ pages_purge(void *addr, size_t length)
# define JEMALLOC_MADV_PURGE MADV_FREE # define JEMALLOC_MADV_PURGE MADV_FREE
# define JEMALLOC_MADV_ZEROS false # define JEMALLOC_MADV_ZEROS false
# else # else
# error "No method defined for purging unused dirty pages." # error "No madvise(2) flag defined for purging unused dirty pages."
# endif # endif
int err = madvise(addr, length, JEMALLOC_MADV_PURGE); int err = madvise(addr, length, JEMALLOC_MADV_PURGE);
unzeroed = (JEMALLOC_MADV_ZEROS == false || err != 0); unzeroed = (JEMALLOC_MADV_ZEROS == false || err != 0);
# undef JEMALLOC_MADV_PURGE # undef JEMALLOC_MADV_PURGE
# undef JEMALLOC_MADV_ZEROS # undef JEMALLOC_MADV_ZEROS
#else
/* Last resort no-op. */
unzeroed = true;
#endif #endif
return (unzeroed); return (unzeroed);
} }