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[Sanitizers] Set default allocator_release_to_os_interval_ms to 5 seconds 

Summary:
With new release to OS approach (see D38245) it's reasonable to enable
it by default. Setting allocator_release_to_os_interval_ms to 5000 seems
to be a reasonable default (might be tuned later, based on the
feedback).

Also delaying the first release to OS in each bucket for at least
allocator_release_to_os_interval_ms after the first allocation to
prevent just allocated memory to be madvised back to OS and let short
lived processes to avoid release to OS overhead altogether.

Reviewers: cryptoad

Subscribers: kubamracek, llvm-commits, mehdi_amini

Differential Revision: https://reviews.llvm.org/D39318

llvm-svn: 316683
This commit is contained in:
Alex Shlyapnikov 2017-10-26 17:59:24 +00:00
parent 593ec59c7e
commit 9b4e32785a
2 changed files with 13 additions and 7 deletions
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8
compiler-rt/lib/sanitizer_common/sanitizer_allocator_primary64.h
View File

@ -669,10 +669,16 @@ class SizeClassAllocator64 {
// Map more space for chunks, if necessary.
if (new_space_end > region->mapped_user) {
if (UNLIKELY(region->mapped_user == 0)) {
if (!kUsingConstantSpaceBeg && kRandomShuffleChunks)
if (UNLIKELY(region->mapped_user == 0))
// The random state is initialized from ASLR.
region->rand_state = static_cast<u32>(region_beg >> 12);
// Postpone the first release to OS attempt for ReleaseToOSIntervalMs,
// preventing just allocated memory from being released sooner than
// necessary and also preventing extraneous ReleaseMemoryPagesToOS calls
// for short lived processes.
region->rtoi.last_release_at_ns = NanoTime();
}
// Do the mmap for the user memory.
uptr map_size = kUserMapSize;
while (new_space_end > region->mapped_user + map_size)

10
compiler-rt/lib/sanitizer_common/sanitizer_flags.inc
View File

@ -129,11 +129,11 @@ COMMON_FLAG(uptr, soft_rss_limit_mb, 0,
" This limit does not affect memory allocations other than"
" malloc/new.")
COMMON_FLAG(bool, heap_profile, false, "Experimental heap profiler, asan-only")
COMMON_FLAG(s32, allocator_release_to_os_interval_ms, kReleaseToOSIntervalNever,
"Experimental. Only affects a 64-bit allocator. If set, tries to "
"release unused memory to the OS, but not more often than this "
"interval (in milliseconds). Negative values mean do not attempt "
"to release memory to the OS.\n")
COMMON_FLAG(s32, allocator_release_to_os_interval_ms, 5000,
"Only affects a 64-bit allocator. If set, tries to release unused "
"memory to the OS, but not more often than this interval (in "
"milliseconds). Negative values mean do not attempt to release "
"memory to the OS.\n")
COMMON_FLAG(bool, can_use_proc_maps_statm, true,
"If false, do not attempt to read /proc/maps/statm."
" Mostly useful for testing sanitizers.")