diff options
author | Kostya Kortchinsky <kostyak@google.com> | 2017-04-20 18:07:17 +0000 |
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committer | Kostya Kortchinsky <kostyak@google.com> | 2017-04-20 18:07:17 +0000 |
commit | ba4bcb3734311880844d4802a46333de9040d996 (patch) | |
tree | f99e5bcb110e3f5b1a5a84e67d2f50bbc864efd3 /lib/scudo/scudo_allocator.h | |
parent | ac9e6ea23b96de782d512ffd7a0dd71e88c0798d (diff) |
[scudo] Remove GetActuallyAllocatedSize calls from the fast path
Summary:
GetActuallyAllocatedSize is actually expensive. In order to avoid calling this
function in the malloc/free fast path, we change the Scudo chunk header to
store the size of the chunk, if from the Primary, or the amount of unused
bytes if from the Secondary. This way, we only have to call the culprit
function for Secondary backed allocations (and still in realloc).
The performance gain on a singly threaded pure malloc/free benchmark exercising
the Primary allocator is above 5%.
Reviewers: alekseyshl, kcc, dvyukov
Reviewed By: dvyukov
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32299
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@300861 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/scudo/scudo_allocator.h')
-rw-r--r-- | lib/scudo/scudo_allocator.h | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/lib/scudo/scudo_allocator.h b/lib/scudo/scudo_allocator.h index 1696e1389..e7428f170 100644 --- a/lib/scudo/scudo_allocator.h +++ b/lib/scudo/scudo_allocator.h @@ -44,15 +44,17 @@ enum ChunkState : u8 { // well. The header will be atomically loaded and stored. typedef u64 PackedHeader; struct UnpackedHeader { - u64 Checksum : 16; - u64 UnusedBytes : 20; // Needed for reallocation purposes. - u64 State : 2; // available, allocated, or quarantined - u64 AllocType : 2; // malloc, new, new[], or memalign - u64 Offset : 16; // Offset from the beginning of the backend - // allocation to the beginning of the chunk itself, - // in multiples of MinAlignment. See comment about - // its maximum value and test in init(). - u64 Salt : 8; + u64 Checksum : 16; + u64 SizeOrUnusedBytes : 19; // Size for Primary backed allocations, amount of + // unused bytes in the chunk for Secondary ones. + u64 FromPrimary : 1; + u64 State : 2; // available, allocated, or quarantined + u64 AllocType : 2; // malloc, new, new[], or memalign + u64 Offset : 16; // Offset from the beginning of the backend + // allocation to the beginning of the chunk + // itself, in multiples of MinAlignment. See + /// comment about its maximum value and in init(). + u64 Salt : 8; }; typedef atomic_uint64_t AtomicPackedHeader; |