Revert "[scudo] Support partial page releasing"
This reverts commit 9c26f51f5e178ac0fda98419e3a61d205d3b58b1.
GitOrigin-RevId: 1cf1b36112b3d475d443909881b02799b548e6b8
diff --git a/lib/scudo/standalone/local_cache.h b/lib/scudo/standalone/local_cache.h
index 6e5b09f..7f27047 100644
--- a/lib/scudo/standalone/local_cache.h
+++ b/lib/scudo/standalone/local_cache.h
@@ -65,13 +65,6 @@
uptr GroupId;
// Cache value of TransferBatch::getMaxCached()
u16 MaxCachedPerBatch;
- // Number of blocks pushed into this group. This is an increment-only
- // counter.
- uptr PushedBlocks;
- // This is used to track how many blocks are pushed since last time we
- // checked `PushedBlocks`. It's useful for page releasing to determine the
- // usage of a BatchGroup.
- uptr PushedBlocksAtLastCheckpoint;
// Blocks are managed by TransferBatch in a list.
SinglyLinkedList<TransferBatch> Batches;
};
diff --git a/lib/scudo/standalone/primary32.h b/lib/scudo/standalone/primary32.h
index fb6cb53..b411a3b 100644
--- a/lib/scudo/standalone/primary32.h
+++ b/lib/scudo/standalone/primary32.h
@@ -421,8 +421,6 @@
BG->GroupId = GroupId;
BG->Batches.push_front(TB);
- BG->PushedBlocks = 0;
- BG->PushedBlocksAtLastCheckpoint = 0;
BG->MaxCachedPerBatch =
TransferBatch::getMaxCached(getSizeByClassId(ClassId));
@@ -448,8 +446,6 @@
CurBatch->appendFromArray(&Array[I], AppendSize);
I += AppendSize;
}
-
- BG->PushedBlocks += Size;
};
BatchGroup *Cur = Sci->FreeList.front();
@@ -656,13 +652,16 @@
if (BytesPushed < PageSize)
return 0; // Nothing new to release.
- const bool CheckDensity = BlockSize < PageSize / 16U;
// Releasing smaller blocks is expensive, so we want to make sure that a
// significant amount of bytes are free, and that there has been a good
// amount of batches pushed to the freelist before attempting to release.
- if (CheckDensity) {
+ if (BlockSize < PageSize / 16U) {
if (!Force && BytesPushed < Sci->AllocatedUser / 16U)
return 0;
+ // We want 8x% to 9x% free bytes (the larger the block, the lower the %).
+ if ((BytesInFreeList * 100U) / Sci->AllocatedUser <
+ (100U - 1U - BlockSize / 16U))
+ return 0;
}
if (!Force) {
@@ -683,47 +682,17 @@
uptr TotalReleasedBytes = 0;
const uptr Base = First * RegionSize;
const uptr NumberOfRegions = Last - First + 1U;
- const uptr GroupSize = (1U << GroupSizeLog);
- const uptr CurRegionGroupId =
- compactPtrGroup(compactPtr(ClassId, Sci->CurrentRegion));
-
ReleaseRecorder Recorder(Base);
- PageReleaseContext Context(BlockSize, RegionSize, NumberOfRegions);
-
- auto DecompactPtr = [](CompactPtrT CompactPtr) {
- return reinterpret_cast<uptr>(CompactPtr);
- };
- for (BatchGroup &BG : Sci->FreeList) {
- const uptr PushedBytesDelta =
- BG.PushedBlocks - BG.PushedBlocksAtLastCheckpoint;
- if (PushedBytesDelta * BlockSize < PageSize)
- continue;
-
- uptr AllocatedGroupSize =
- BG.GroupId == CurRegionGroupId ? Sci->CurrentRegionAllocated :
- GroupSize;
- if (AllocatedGroupSize == 0) continue;
-
- const uptr NumBlocks = (BG.Batches.size() - 1) * BG.MaxCachedPerBatch +
- BG.Batches.back()->getCount();
- const uptr BytesInBG = NumBlocks * BlockSize;
- // Given the randomness property, we try to release the pages only if the
- // bytes used by free blocks exceed certain proportion of allocated
- // spaces.
- if (CheckDensity && (BytesInBG * 100U) / AllocatedGroupSize <
- (100U - 1U - BlockSize / 16U)) {
- continue;
- }
-
- BG.PushedBlocksAtLastCheckpoint = BG.PushedBlocks;
- // Note that we don't always visit blocks in each BatchGroup so that we
- // may miss the chance of releasing certain pages that cross BatchGroups.
- Context.markFreeBlocks(BG.Batches, DecompactPtr, Base);
- }
-
auto SkipRegion = [this, First, ClassId](uptr RegionIndex) {
return (PossibleRegions[First + RegionIndex] - 1U) != ClassId;
};
+ auto DecompactPtr = [](CompactPtrT CompactPtr) {
+ return reinterpret_cast<uptr>(CompactPtr);
+ };
+ PageReleaseContext Context(BlockSize, RegionSize, NumberOfRegions);
+ for (BatchGroup &BG : Sci->FreeList)
+ Context.markFreeBlocks(BG.Batches, DecompactPtr, Base);
+
releaseFreeMemoryToOS(Context, Recorder, SkipRegion);
if (Recorder.getReleasedRangesCount() > 0) {
diff --git a/lib/scudo/standalone/primary64.h b/lib/scudo/standalone/primary64.h
index 2b6e71c..84b811a 100644
--- a/lib/scudo/standalone/primary64.h
+++ b/lib/scudo/standalone/primary64.h
@@ -370,9 +370,6 @@
static uptr compactPtrGroup(CompactPtrT CompactPtr) {
return CompactPtr >> (GroupSizeLog - CompactPtrScale);
}
- static uptr batchGroupBase(uptr Base, uptr GroupId) {
- return (GroupId << GroupSizeLog) + Base;
- }
// Push the blocks to their batch group. The layout will be like,
//
@@ -427,8 +424,6 @@
BG->GroupId = GroupId;
BG->Batches.push_front(TB);
- BG->PushedBlocks = 0;
- BG->PushedBlocksAtLastCheckpoint = 0;
BG->MaxCachedPerBatch =
TransferBatch::getMaxCached(getSizeByClassId(ClassId));
@@ -455,8 +450,6 @@
CurBatch->appendFromArray(&Array[I], AppendSize);
I += AppendSize;
}
-
- BG->PushedBlocks += Size;
};
BatchGroup *Cur = Region->FreeList.front();
@@ -668,13 +661,16 @@
if (BytesPushed < PageSize)
return 0; // Nothing new to release.
- bool CheckDensity = BlockSize < PageSize / 16U;
// Releasing smaller blocks is expensive, so we want to make sure that a
// significant amount of bytes are free, and that there has been a good
// amount of batches pushed to the freelist before attempting to release.
- if (CheckDensity) {
+ if (BlockSize < PageSize / 16U) {
if (!Force && BytesPushed < Region->AllocatedUser / 16U)
return 0;
+ // We want 8x% to 9x% free bytes (the larger the block, the lower the %).
+ if ((BytesInFreeList * 100U) / Region->AllocatedUser <
+ (100U - 1U - BlockSize / 16U))
+ return 0;
}
if (!Force) {
@@ -688,46 +684,16 @@
}
}
- const uptr GroupSize = (1U << GroupSizeLog);
- const uptr AllocatedUserEnd = Region->AllocatedUser + Region->RegionBeg;
ReleaseRecorder Recorder(Region->RegionBeg, &Region->Data);
- PageReleaseContext Context(BlockSize, RegionSize, /*NumberOfRegions=*/1U);
-
const uptr CompactPtrBase = getCompactPtrBaseByClassId(ClassId);
auto DecompactPtr = [CompactPtrBase](CompactPtrT CompactPtr) {
return decompactPtrInternal(CompactPtrBase, CompactPtr);
};
- for (BatchGroup &BG : Region->FreeList) {
- const uptr PushedBytesDelta =
- BG.PushedBlocks - BG.PushedBlocksAtLastCheckpoint;
- if (PushedBytesDelta * BlockSize < PageSize)
- continue;
- const uptr BatchGroupEnd =
- batchGroupBase(BG.GroupId, CompactPtrBase) + GroupSize;
- const uptr AllocatedGroupSize =
- AllocatedUserEnd >= BatchGroupEnd ? GroupSize :
- AllocatedUserEnd - BatchGroupEnd;
- if (AllocatedGroupSize == 0) continue;
-
- const uptr NumBlocks = (BG.Batches.size() - 1) * BG.MaxCachedPerBatch +
- BG.Batches.back()->getCount();
- const uptr BytesInBG = NumBlocks * BlockSize;
- // Given the randomness property, we try to release the pages only if the
- // bytes used by free blocks exceed certain proportion of group size. Note
- // that this heuristic only applies when all the spaces in a BatchGroup
- // are allocated.
- if (CheckDensity && (BytesInBG * 100U) / AllocatedGroupSize <
- (100U - 1U - BlockSize / 16U)) {
- continue;
- }
-
- BG.PushedBlocksAtLastCheckpoint = BG.PushedBlocks;
- // Note that we don't always visit blocks in each BatchGroup so that we
- // may miss the chance of releasing certain pages that cross BatchGroups.
- Context.markFreeBlocks(BG.Batches, DecompactPtr, Region->RegionBeg);
- }
-
auto SkipRegion = [](UNUSED uptr RegionIndex) { return false; };
+ PageReleaseContext Context(BlockSize, RegionSize, /*NumberOfRegions=*/1U);
+ for (BatchGroup &BG : Region->FreeList)
+ Context.markFreeBlocks(BG.Batches, DecompactPtr, Region->RegionBeg);
+
releaseFreeMemoryToOS(Context, Recorder, SkipRegion);
if (Recorder.getReleasedRangesCount() > 0) {
diff --git a/lib/scudo/standalone/tests/combined_test.cpp b/lib/scudo/standalone/tests/combined_test.cpp
index 02a6e04..5b9d471 100644
--- a/lib/scudo/standalone/tests/combined_test.cpp
+++ b/lib/scudo/standalone/tests/combined_test.cpp
@@ -506,7 +506,7 @@
static const scudo::uptr MinSizeLog = 10;
static const scudo::uptr MidSizeLog = 10;
static const scudo::uptr MaxSizeLog = 13;
- static const scudo::u16 MaxNumCachedHint = 8;
+ static const scudo::u16 MaxNumCachedHint = 4;
static const scudo::uptr MaxBytesCachedLog = 12;
static const scudo::uptr SizeDelta = 0;
};
