Title: [276155] trunk/Source/_javascript_Core
- Revision
- 276155
- Author
- keith_mil...@apple.com
- Date
- 2021-04-16 12:24:22 -0700 (Fri, 16 Apr 2021)
Log Message
Before deleting a MarkedBlock we do not need to clear its m_directory pointer.
https://bugs.webkit.org/show_bug.cgi?id=224677
Reviewed by Yusuke Suzuki.
Right now when we are about to free a MarkedBlock we clear the
m_directory pointer in the MarkedBlock's Handle. This has the
downside, however, of potentially paging in the footer from disk /
the compressor, which some data we have seen shows is happening.
This patch prevents this uncessary store to hopefully reduce the
number of pageins/decompressions caused by Safari web content.
* heap/BlockDirectory.cpp:
(JSC::BlockDirectory::removeBlock):
(JSC::BlockDirectory::removeBlockForDeletion):
* heap/BlockDirectory.h:
* heap/MarkedBlock.cpp:
(JSC::MarkedBlock::Handle::~Handle):
* heap/MarkedSpace.cpp:
(JSC::MarkedSpace::freeBlock):
Modified Paths
Diff
Modified: trunk/Source/_javascript_Core/ChangeLog (276154 => 276155)
--- trunk/Source/_javascript_Core/ChangeLog 2021-04-16 19:22:56 UTC (rev 276154)
+++ trunk/Source/_javascript_Core/ChangeLog 2021-04-16 19:24:22 UTC (rev 276155)
@@ -1,3 +1,26 @@
+2021-04-16 Keith Miller <keith_mil...@apple.com>
+
+ Before deleting a MarkedBlock we do not need to clear its m_directory pointer.
+ https://bugs.webkit.org/show_bug.cgi?id=224677
+
+ Reviewed by Yusuke Suzuki.
+
+ Right now when we are about to free a MarkedBlock we clear the
+ m_directory pointer in the MarkedBlock's Handle. This has the
+ downside, however, of potentially paging in the footer from disk /
+ the compressor, which some data we have seen shows is happening.
+ This patch prevents this uncessary store to hopefully reduce the
+ number of pageins/decompressions caused by Safari web content.
+
+ * heap/BlockDirectory.cpp:
+ (JSC::BlockDirectory::removeBlock):
+ (JSC::BlockDirectory::removeBlockForDeletion):
+ * heap/BlockDirectory.h:
+ * heap/MarkedBlock.cpp:
+ (JSC::MarkedBlock::Handle::~Handle):
+ * heap/MarkedSpace.cpp:
+ (JSC::MarkedSpace::freeBlock):
+
2021-04-16 Mark Lam <mark....@apple.com>
Build fix for Debug -O3 after r276069.
Modified: trunk/Source/_javascript_Core/heap/BlockDirectory.cpp (276154 => 276155)
--- trunk/Source/_javascript_Core/heap/BlockDirectory.cpp 2021-04-16 19:22:56 UTC (rev 276154)
+++ trunk/Source/_javascript_Core/heap/BlockDirectory.cpp 2021-04-16 19:24:22 UTC (rev 276155)
@@ -140,7 +140,7 @@
setIsEmpty(NoLockingNecessary, index, true);
}
-void BlockDirectory::removeBlock(MarkedBlock::Handle* block)
+void BlockDirectory::removeBlock(MarkedBlock::Handle* block, WillDeleteBlock willDelete)
{
ASSERT(block->directory() == this);
ASSERT(m_blocks[block->index()] == block);
@@ -155,8 +155,9 @@
[&](auto vectorRef) {
vectorRef[block->index()] = false;
});
-
- block->didRemoveFromDirectory();
+
+ if (willDelete == WillDeleteBlock::No)
+ block->didRemoveFromDirectory();
}
void BlockDirectory::stopAllocating()
Modified: trunk/Source/_javascript_Core/heap/BlockDirectory.h (276154 => 276155)
--- trunk/Source/_javascript_Core/heap/BlockDirectory.h 2021-04-16 19:22:56 UTC (rev 276154)
+++ trunk/Source/_javascript_Core/heap/BlockDirectory.h 2021-04-16 19:24:22 UTC (rev 276155)
@@ -83,7 +83,9 @@
RefPtr<SharedTask<MarkedBlock::Handle*()>> parallelNotEmptyBlockSource();
void addBlock(MarkedBlock::Handle*);
- void removeBlock(MarkedBlock::Handle*);
+ enum class WillDeleteBlock { No, Yes };
+ // If WillDeleteBlock::Yes is passed then the block will be left in an invalid state. We do this, however, to avoid potentially paging in / decompressing old blocks to update their handle just before freeing them.
+ void removeBlock(MarkedBlock::Handle*, WillDeleteBlock = WillDeleteBlock::No);
bool isPagedOut(MonotonicTime deadline);
Modified: trunk/Source/_javascript_Core/heap/MarkedBlock.cpp (276154 => 276155)
--- trunk/Source/_javascript_Core/heap/MarkedBlock.cpp 2021-04-16 19:22:56 UTC (rev 276154)
+++ trunk/Source/_javascript_Core/heap/MarkedBlock.cpp 2021-04-16 19:24:22 UTC (rev 276155)
@@ -76,7 +76,7 @@
if (!(balance % 10))
dataLog("MarkedBlock Balance: ", balance, "\n");
}
- removeFromDirectory();
+ m_directory->removeBlock(this, BlockDirectory::WillDeleteBlock::Yes);
m_block->~MarkedBlock();
m_alignedMemoryAllocator->freeAlignedMemory(m_block);
heap.didFreeBlock(blockSize);
Modified: trunk/Source/_javascript_Core/heap/MarkedSpace.cpp (276154 => 276155)
--- trunk/Source/_javascript_Core/heap/MarkedSpace.cpp 2021-04-16 19:22:56 UTC (rev 276154)
+++ trunk/Source/_javascript_Core/heap/MarkedSpace.cpp 2021-04-16 19:24:22 UTC (rev 276155)
@@ -375,7 +375,6 @@
void MarkedSpace::freeBlock(MarkedBlock::Handle* block)
{
- block->directory()->removeBlock(block);
m_capacity -= MarkedBlock::blockSize;
m_blocks.remove(&block->block());
delete block;
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