Title: [198545] trunk/Source/bmalloc
- Revision
- 198545
- Author
- [email protected]
- Date
- 2016-03-22 12:39:12 -0700 (Tue, 22 Mar 2016)
Log Message
bmalloc: shrink largeMax
https://bugs.webkit.org/show_bug.cgi?id=155759
Reviewed by Michael Saboff.
If a largeChunk contains N bytes and we allocate objects of size
N / 2 + 8 bytes, then we waste 50% of physical memory at peak.
This patch sets largeMax to N / 2, reducing maximum waste to 25%.
* bmalloc/BoundaryTag.h:
* bmalloc/LargeChunk.h:
(bmalloc::LargeChunk::LargeChunk):
* bmalloc/SegregatedFreeList.cpp:
(bmalloc::SegregatedFreeList::SegregatedFreeList):
(bmalloc::SegregatedFreeList::insert): Honor largeMax vs largeObjectMax.
* bmalloc/Sizes.h: Distinguish between the largest thing we can store
in a free list (largeObjectMax) and the largest thing we're willing to
allocate (largeMax).
Modified Paths
Diff
Modified: trunk/Source/bmalloc/ChangeLog (198544 => 198545)
--- trunk/Source/bmalloc/ChangeLog 2016-03-22 19:21:53 UTC (rev 198544)
+++ trunk/Source/bmalloc/ChangeLog 2016-03-22 19:39:12 UTC (rev 198545)
@@ -1,3 +1,26 @@
+2016-03-22 Geoffrey Garen <[email protected]>
+
+ bmalloc: shrink largeMax
+ https://bugs.webkit.org/show_bug.cgi?id=155759
+
+ Reviewed by Michael Saboff.
+
+ If a largeChunk contains N bytes and we allocate objects of size
+ N / 2 + 8 bytes, then we waste 50% of physical memory at peak.
+
+ This patch sets largeMax to N / 2, reducing maximum waste to 25%.
+
+ * bmalloc/BoundaryTag.h:
+ * bmalloc/LargeChunk.h:
+ (bmalloc::LargeChunk::LargeChunk):
+ * bmalloc/SegregatedFreeList.cpp:
+ (bmalloc::SegregatedFreeList::SegregatedFreeList):
+ (bmalloc::SegregatedFreeList::insert): Honor largeMax vs largeObjectMax.
+
+ * bmalloc/Sizes.h: Distinguish between the largest thing we can store
+ in a free list (largeObjectMax) and the largest thing we're willing to
+ allocate (largeMax).
+
2016-03-20 Dan Bernstein <[email protected]>
[Mac] Determine TARGET_MAC_OS_X_VERSION_MAJOR from MACOSX_DEPLOYMENT_TARGET rather than from MAC_OS_X_VERSION_MAJOR
Modified: trunk/Source/bmalloc/bmalloc/BoundaryTag.h (198544 => 198545)
--- trunk/Source/bmalloc/bmalloc/BoundaryTag.h 2016-03-22 19:21:53 UTC (rev 198544)
+++ trunk/Source/bmalloc/bmalloc/BoundaryTag.h 2016-03-22 19:39:12 UTC (rev 198545)
@@ -80,8 +80,8 @@
"compactBegin must be encodable in a BoundaryTag.");
static_assert(
- (1 << sizeBits) - 1 >= largeMax,
- "largeMax must be encodable in a BoundaryTag.");
+ (1 << sizeBits) - 1 >= largeObjectMax,
+ "largeObjectMax must be encodable in a BoundaryTag.");
bool m_isFree: 1;
bool m_isEnd: 1;
Modified: trunk/Source/bmalloc/bmalloc/LargeChunk.h (198544 => 198545)
--- trunk/Source/bmalloc/bmalloc/LargeChunk.h 2016-03-22 19:21:53 UTC (rev 198544)
+++ trunk/Source/bmalloc/bmalloc/LargeChunk.h 2016-03-22 19:39:12 UTC (rev 198545)
@@ -69,12 +69,12 @@
};
static_assert(largeChunkMetadataSize == sizeof(LargeChunk), "Our largeChunkMetadataSize math in Sizes.h is wrong");
-static_assert(largeChunkMetadataSize + largeMax == largeChunkSize, "largeMax is too small or too big");
+static_assert(largeChunkMetadataSize + largeObjectMax == largeChunkSize, "largeObjectMax is too small or too big");
inline LargeChunk::LargeChunk()
{
Range range(begin(), end() - begin());
- BASSERT(range.size() == largeMax);
+ BASSERT(range.size() == largeObjectMax);
BeginTag* beginTag = LargeChunk::beginTag(range.begin());
beginTag->setRange(range);
Modified: trunk/Source/bmalloc/bmalloc/SegregatedFreeList.cpp (198544 => 198545)
--- trunk/Source/bmalloc/bmalloc/SegregatedFreeList.cpp 2016-03-22 19:21:53 UTC (rev 198544)
+++ trunk/Source/bmalloc/bmalloc/SegregatedFreeList.cpp 2016-03-22 19:39:12 UTC (rev 198545)
@@ -30,7 +30,7 @@
SegregatedFreeList::SegregatedFreeList(VMState::HasPhysical hasPhysical)
: m_hasPhysical(hasPhysical)
{
- BASSERT(static_cast<size_t>(&select(largeMax) - m_freeLists.begin()) == m_freeLists.size() - 1);
+ BASSERT(static_cast<size_t>(&select(largeObjectMax) - m_freeLists.begin()) == m_freeLists.size() - 1);
}
void SegregatedFreeList::insert(const LargeObject& largeObject)
Modified: trunk/Source/bmalloc/bmalloc/Sizes.h (198544 => 198545)
--- trunk/Source/bmalloc/bmalloc/Sizes.h 2016-03-22 19:21:53 UTC (rev 198544)
+++ trunk/Source/bmalloc/bmalloc/Sizes.h 2016-03-22 19:39:12 UTC (rev 198545)
@@ -71,7 +71,8 @@
static const size_t largeAlignment = 64;
static const size_t largeMin = smallMax;
static const size_t largeChunkMetadataSize = 4 * kB; // sizeof(LargeChunk)
- static const size_t largeMax = largeChunkSize - largeChunkMetadataSize;
+ static const size_t largeObjectMax = largeChunkSize - largeChunkMetadataSize;
+ static const size_t largeMax = largeObjectMax / 2;
static const size_t xLargeAlignment = superChunkSize;
static const size_t xLargeMask = ~(xLargeAlignment - 1);
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