weaselab/conflict-set
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Enforce free list memory bound by tracking bytes directly

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This commit is contained in:
Andrew Noyes
2024-03-08 21:46:35 -08:00
parent 504a93bb10
commit e32bea7b29
1 changed files with 11 additions and 8 deletions
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19
ConflictSet.cpp
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@@ -260,7 +260,7 @@ static_assert(sizeof(Node4) < kMinChildrenNode4 * kBytesPerKey);
// Bounds memory usage in free list, but does not account for memory for partial
// keys.
template <class T, size_t kMemoryBound = (1 << 20)>
template <class T, int64_t kMemoryBound = (1 << 20)>
struct BoundedFreeListAllocator {
static_assert(sizeof(T) >= sizeof(void *));
static_assert(std::derived_from<T, Node>);
@@ -275,12 +275,15 @@ struct BoundedFreeListAllocator {
VALGRIND_MAKE_MEM_UNDEFINED(n, sizeof(T));
VALGRIND_MAKE_MEM_DEFINED(&n->partialKeyCapacity,
sizeof(n->partialKeyCapacity));
if (n->partialKeyCapacity >= partialKeyCapacity) {
VALGRIND_MAKE_MEM_DEFINED(freeList, sizeof(freeList));
memcpy(&freeList, freeList, sizeof(freeList));
--freeListSize;
freeListBytes -= sizeof(T) + n->partialKeyCapacity;
if (n->partialKeyCapacity >= partialKeyCapacity) {
return new (n) T;
} else {
// The intent is to filter out too-small nodes in the freelist
free(n);
}
VALGRIND_MAKE_MEM_NOACCESS(n, sizeof(T));
}
auto *result = new (safe_malloc(sizeof(T) + partialKeyCapacity)) T;
@@ -293,12 +296,12 @@ struct BoundedFreeListAllocator {
--liveAllocations;
#endif
static_assert(std::is_trivially_destructible_v<T>);
if (freeListSize == kMaxFreeListSize) {
if (freeListBytes >= kMemoryBound) {
return free(p);
}
memcpy((void *)p, &freeList, sizeof(freeList));
freeList = p;
++freeListSize;
freeListBytes += sizeof(T) + p->partialKeyCapacity;
VALGRIND_MAKE_MEM_NOACCESS(freeList, sizeof(T));
}
@@ -316,10 +319,10 @@ struct BoundedFreeListAllocator {
#endif
private:
static constexpr int kMaxFreeListSize = kMemoryBound / sizeof(T);
int freeListSize = 0;
int64_t freeListBytes = 0;
void *freeList = nullptr;
#if SHOW_MEMORY
// TODO Track partial key bytes
int64_t maxLiveAllocations = 0;
int64_t liveAllocations = 0;
#endif