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libpas(win): release TLC commit charge on scavenge; harden VirtualQuery #185

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libpas(win): release TLC commit charge on scavenge; harden VirtualQuery #185

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3 changes: 2 additions & 1 deletion Source/JavaScriptCore/heap/StructureAlignedMemoryAllocator.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -158,7 +158,8 @@ class StructureMemoryManager {
#if OS(WINDOWS) || PLATFORM(PLAYSTATION)
// libpas isn't calling pas_page_malloc commit, so we've got to commit the region ourselves
// https://bugs.webkit.org/show_bug.cgi?id=292771
OSAllocator::commit(result, MarkedBlock::blockSize, true, false);
if (result) [[likely]]
OSAllocator::commit(result, MarkedBlock::blockSize, true, false);
#endif
return result;
#elif USE(MIMALLOC)
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17 changes: 9 additions & 8 deletions Source/bmalloc/libpas/src/libpas/pas_page_malloc.c
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Expand Up @@ -387,7 +387,7 @@ static void commit_impl(void* ptr, size_t size, bool do_mprotect, pas_mmap_capab
void *currentPtr = ptr;
while (totalSeen < size) {
MEMORY_BASIC_INFORMATION memInfo;
VirtualQuery(currentPtr, &memInfo, sizeof(memInfo));
PAS_ASSERT(VirtualQuery(currentPtr, &memInfo, sizeof(memInfo)));
PAS_ASSERT(memInfo.State != 0x10000);
PAS_ASSERT(memInfo.RegionSize > 0);
PAS_ASSERT(virtual_alloc_with_retry(currentPtr, PAS_MIN(memInfo.RegionSize, size - totalSeen), MEM_COMMIT, PAGE_READWRITE));
Expand Down Expand Up @@ -456,25 +456,26 @@ static void decommit_impl(void* ptr, size_t size,
void* currentPtr = ptr;
while (totalSeen < size) {
MEMORY_BASIC_INFORMATION memInfo;
VirtualQuery(currentPtr, &memInfo, sizeof(memInfo));
PAS_ASSERT(VirtualQuery(currentPtr, &memInfo, sizeof(memInfo)));
PAS_ASSERT(memInfo.RegionSize > 0);
PAS_ASSERT(VirtualFree(currentPtr, PAS_MIN(memInfo.RegionSize, size - totalSeen), MEM_DECOMMIT));
currentPtr = (void*)((uintptr_t)currentPtr + memInfo.RegionSize);
totalSeen += memInfo.RegionSize;
}
}
} else {
/* do_mprotect=false callers (pas_expendable_memory) read payload directly
and rely on seeing zeros after decommit, like MADV_FREE. MEM_DECOMMIT
would make those reads AV, so use DiscardVirtualMemory which frees
physical RAM but keeps pages accessible. This does not release commit
charge, but expendable memory is bounded metadata. */
/* The only do_mprotect=false caller is pas_expendable_memory, which reads
payload directly and relies on seeing zeros after decommit, like
MADV_FREE. MEM_DECOMMIT would make those reads AV, so use
DiscardVirtualMemory which frees physical RAM but keeps pages
accessible. This does not release commit charge, but expendable memory
is bounded metadata. */
if (DiscardVirtualMemory(ptr, size)) {
size_t totalSeen = 0;
void* currentPtr = ptr;
while (totalSeen < size) {
MEMORY_BASIC_INFORMATION memInfo;
VirtualQuery(currentPtr, &memInfo, sizeof(memInfo));
PAS_ASSERT(VirtualQuery(currentPtr, &memInfo, sizeof(memInfo)));
PAS_ASSERT(memInfo.RegionSize > 0);
PAS_ASSERT(VirtualAlloc(currentPtr, PAS_MIN(memInfo.RegionSize, size - totalSeen), MEM_RESET, PAGE_READWRITE));
currentPtr = (void*)((uintptr_t)currentPtr + memInfo.RegionSize);
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6 changes: 3 additions & 3 deletions Source/bmalloc/libpas/src/libpas/pas_thread_local_cache.c
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Expand Up @@ -122,7 +122,7 @@ static void deallocate(pas_thread_local_cache* thread_local_cache)
thread_local_cache->allocator_index_capacity);

/* If we're doing symmetric decommit, then we need to commit the memory for the TLC now. */
pas_page_malloc_commit_without_mprotect(begin, size, pas_may_mmap);
pas_page_malloc_commit(begin, size, pas_may_mmap);

pas_large_utility_free_heap_deallocate(begin, size);
}
Expand Down Expand Up @@ -512,7 +512,7 @@ void pas_thread_local_cache_ensure_committed(pas_thread_local_cache* thread_loca

/* Don't attempt to do fancy things with spans for commit, since we're no longer really
optimizing for symmetric commit anyway. */
pas_page_malloc_commit_without_mprotect(
pas_page_malloc_commit(
(char*)thread_local_cache + (page_index << pas_page_malloc_alignment_shift()),
pas_page_malloc_alignment(),
pas_may_mmap);
Expand Down Expand Up @@ -996,7 +996,7 @@ static void decommit_allocator_range(pas_thread_local_cache* cache,
if (verbose)
pas_log("Decommitting %p...%p\n", (void*)decommit_range.begin, (void*)decommit_range.end);

pas_page_malloc_decommit_without_mprotect(
pas_page_malloc_decommit(
(char*)cache + decommit_range.begin, pas_range_size(decommit_range), pas_may_mmap);

if (verbose) {
Expand Down
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