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scudo: Don't memset previously released cached pages in the secondary allocator. 

There is no need to memset released pages because they are already
zero. On db845c, before:

BM_stdlib_malloc_free_default/131072      34562 ns        34547 ns        20258 bytes_per_second=3.53345G/s

after:

BM_stdlib_malloc_free_default/131072      29618 ns        29589 ns        23485 bytes_per_second=4.12548G/s

Differential Revision: https://reviews.llvm.org/D90814
This commit is contained in:
Peter Collingbourne 2020-11-03 18:00:40 -08:00
parent 5e34877480
commit ee7b629df2
1 changed files with 7 additions and 4 deletions
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11
compiler-rt/lib/scudo/standalone/secondary.h
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@ -52,7 +52,8 @@ class MapAllocatorNoCache {
public:
void initLinkerInitialized(UNUSED s32 ReleaseToOsInterval) {}
void init(UNUSED s32 ReleaseToOsInterval) {}
bool retrieve(UNUSED uptr Size, UNUSED LargeBlock::Header **H) {
bool retrieve(UNUSED uptr Size, UNUSED LargeBlock::Header **H,
UNUSED bool *Zeroed) {
return false;
}
bool store(UNUSED LargeBlock::Header *H) { return false; }
@ -126,7 +127,7 @@ public:
return EntryCached;
}
bool retrieve(uptr Size, LargeBlock::Header **H) {
bool retrieve(uptr Size, LargeBlock::Header **H, bool *Zeroed) {
const uptr PageSize = getPageSizeCached();
const u32 MaxCount = atomic_load_relaxed(&MaxEntriesCount);
ScopedLock L(Mutex);
@ -141,6 +142,7 @@ public:
if (Size < BlockSize - PageSize * 4U)
continue;
*H = reinterpret_cast<LargeBlock::Header *>(Entries[I].Block);
*Zeroed = Entries[I].Time == 0;
Entries[I].Block = 0;
(*H)->BlockEnd = Entries[I].BlockEnd;
(*H)->MapBase = Entries[I].MapBase;
@ -328,12 +330,13 @@ void *MapAllocator<CacheT>::allocate(uptr Size, uptr AlignmentHint,
if (AlignmentHint < PageSize && Cache.canCache(RoundedSize)) {
LargeBlock::Header *H;
if (Cache.retrieve(RoundedSize, &H)) {
bool Zeroed;
if (Cache.retrieve(RoundedSize, &H, &Zeroed)) {
if (BlockEnd)
*BlockEnd = H->BlockEnd;
void *Ptr = reinterpret_cast<void *>(reinterpret_cast<uptr>(H) +
LargeBlock::getHeaderSize());
if (FillContents)
if (FillContents && !Zeroed)
memset(Ptr, FillContents == ZeroFill ? 0 : PatternFillByte,
H->BlockEnd - reinterpret_cast<uptr>(Ptr));
const uptr BlockSize = H->BlockEnd - reinterpret_cast<uptr>(H);