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use atomic load for segment map

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daan 2020-09-03 12:19:04 -07:00
parent 03071dec0f
commit 228b5f6e9d
1 changed files with 8 additions and 6 deletions
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14
src/segment.c
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@ -1392,7 +1392,7 @@ static void mi_segment_map_allocated_at(const mi_segment_t* segment) {
size_t index = mi_segment_map_index_of(segment, &bitidx);
mi_assert_internal(index < MI_SEGMENT_MAP_WSIZE);
if (index==0) return;
uintptr_t mask = mi_segment_map[index];
uintptr_t mask = mi_atomic_load_relaxed(&mi_segment_map[index]);
uintptr_t newmask;
do {
newmask = (mask | ((uintptr_t)1 << bitidx));
@ -1404,7 +1404,7 @@ static void mi_segment_map_freed_at(const mi_segment_t* segment) {
size_t index = mi_segment_map_index_of(segment, &bitidx);
mi_assert_internal(index < MI_SEGMENT_MAP_WSIZE);
if (index == 0) return;
uintptr_t mask = mi_segment_map[index];
uintptr_t mask = mi_atomic_load_relaxed(&mi_segment_map[index]);
uintptr_t newmask;
do {
newmask = (mask & ~((uintptr_t)1 << bitidx));
@ -1417,7 +1417,8 @@ static mi_segment_t* _mi_segment_of(const void* p) {
size_t bitidx;
size_t index = mi_segment_map_index_of(segment, &bitidx);
// fast path: for any pointer to valid small/medium/large object or first MI_SEGMENT_SIZE in huge
if (mi_likely((mi_segment_map[index] & ((uintptr_t)1 << bitidx)) != 0)) {
const uintptr_t mask = mi_atomic_load_relaxed(&mi_segment_map[index]);
if (mi_likely((mask & ((uintptr_t)1 << bitidx)) != 0)) {
return segment; // yes, allocated by us
}
if (index==0) return NULL;
@ -1427,16 +1428,17 @@ static mi_segment_t* _mi_segment_of(const void* p) {
// note: we could maintain a lowest index to speed up the path for invalid pointers?
size_t lobitidx;
size_t loindex;
uintptr_t lobits = mi_segment_map[index] & (((uintptr_t)1 << bitidx) - 1);
uintptr_t lobits = mask & (((uintptr_t)1 << bitidx) - 1);
if (lobits != 0) {
loindex = index;
lobitidx = _mi_bsr(lobits);
}
else {
uintptr_t lomask = mask;
loindex = index - 1;
while (loindex > 0 && mi_segment_map[loindex] == 0) loindex--;
while (loindex > 0 && (lomask = mi_atomic_load_relaxed(&mi_segment_map[loindex])) == 0) loindex--;
if (loindex==0) return NULL;
lobitidx = _mi_bsr(mi_segment_map[loindex]);
lobitidx = _mi_bsr(lomask);
}
// take difference as the addresses could be larger than the MAX_ADDRESS space.
size_t diff = (((index - loindex) * (8*MI_INTPTR_SIZE)) + bitidx - lobitidx) * MI_SEGMENT_SIZE;