On x86 Linux, we define our own MADV_FREE if madvise(2) is available, but no
MADV_FREE is detected. This allows the feature to be built in and enabled with
runtime detection.
Since we allocate rtree nodes from a0's base, it's pushed to over 1 block on
initialization right away, which makes the auto thp mode less effective on a0.
We change a0 to make the switch on the 3rd block instead.
Quoting from https://github.com/jemalloc/jemalloc/issues/761 :
[...] reading the Power ISA documentation[1], the assembly in [the CPU_SPINWAIT
macro] isn't correct anyway (as @marxin points out): the setting of the
program-priority register is "sticky", and we never undo the lowering.
We could do something similar, but given that we don't have testing here in the
first place, I'm inclined to simply not try. I'll put something up reverting the
problematic commit tomorrow.
[1] Book II, chapter 3 of the 2.07B or 3.0B ISA documents.
There does not seem to be any overlap between usage of
extent_avail and extent_heap, so we can use the same hook.
The only remaining usage of rb trees is in the profiling code,
which has some 'interesting' iteration constraints.
Fixes#888
In userspace ARM on Linux, zero-ing the high bits is the correct way to do this.
This doesn't fix the fact that we currently set LG_VADDR to 48 on ARM, when in
fact larger virtual address sizes are coming soon. We'll cross that bridge when
we come to it.
It's possible to build with lazy purge enabled but depoly to systems without
such support. In this case, rely on the boot time detection instead of keep
making unnecessary madvise calls (which all returns EINVAL).
We've been seeing strange errors in jemalloc_cpp.cpp since Travis upgraded from
precise to trusty as their default CI environment (seeming to stem from some
the new clang version finding the headers for an old version of libstdc++. In
the long run we'll have to deal with this "for real", but at that point we may
have a better C++ story in general, making it a moot point.
If we guarantee no malloc activity in extent hooks, it's possible to make
customized hooks working on arena 0. Remove the non-a0 assertion to enable such
use cases.
To avoid the high RSS caused by THP + low usage arena (i.e. THP becomes a
significant percentage), added a new "auto" option which will only start using
THP after a base allocator used up the first THP region. Starting from the
second hugepage (in a single arena), "auto" behaves the same as "always",
i.e. madvise hugepage right away.
This eliminates the need for the arena stats code to "know" about tcaches; all
that it needs is a cache_bin_array_descriptor_t to tell it where to find
cache_bins whose stats it should aggregate.
This is the first step towards breaking up the tcache and arena (since they
interact primarily at the bin level). It should also make a future arena
caching implementation more straightforward.
The configure.ac seciton right now is the same for Linux and kFreeBSD,
which results into an incorrect configuration of e.g. defining
JEMALLOC_PROC_SYS_VM_OVERCOMMIT_MEMORY instead of FreeBSD's
JEMALLOC_SYSCTL_VM_OVERCOMMIT.
GNU/kFreeBSD is really a glibc + FreeBSD kernel system, so it needs its
own entry which has a mixture of configuration options from Linux and
FreeBSD.
As part of the metadata_thp support, We now have a separate swtich
(JEMALLOC_HAVE_MADVISE_HUGE) for MADV_HUGEPAGE availability. Use that instead
of JEMALLOC_THP (which doesn't guard pages_huge anymore) in tests.
The external linkage for spin_adaptive was not used, and the inline
declaration of spin_adaptive that was used caused a probem on FreeBSD
where CPU_SPINWAIT is implemented as a call to a static procedure for
x86 architectures.
If ptr is not page aligned, we know the allocation was not sampled. In this case
use the size passed into sdallocx directly w/o accessing rtree. This improve
sdallocx efficiency in the common case (not sampled && small allocation).
When retain is enabled, we should not attempt mmap for in-place expansion
(large_ralloc_no_move), because it's virtually impossible to succeed, and causes
unnecessary syscalls (which can cause lock contention under load).
Currently we have to log by writing something like:
static log_var_t log_a_b_c = LOG_VAR_INIT("a.b.c");
log (log_a_b_c, "msg");
This is sort of annoying. Let's just write:
log("a.b.c", "msg");
Currently, the log macro requires at least one argument after the format string,
because of the way the preprocessor handles varargs macros. We can hide some of
that irritation by pushing the extra arguments into a varargs function.
Older Linux systems don't have O_CLOEXEC. If that's the case, we fcntl
immediately after open, to minimize the length of the racy period in
which an
operation in another thread can leak a file descriptor to a child.
Forking a multithreaded process is dangerous but allowed, so long as the child
only executes async-signal-safe functions (e.g. exec). Add a test to ensure
that we don't break this behavior.
On OS X, we rely on the zone machinery to call our prefork and postfork
handlers.
In zone_force_unlock, we call jemalloc_postfork_child, reinitializing all our
mutexes regardless of state, since the mutex implementation will assert if the
tid of the unlocker is different from that of the locker. This has the effect
of unlocking the mutexes, but also fails to wake any threads waiting on them in
the parent.
To fix this, we track whether or not we're the parent or child after the fork,
and unlock or reinit as appropriate.
This resolves#895.
