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Merge branch 'master' into dev

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This commit is contained in:
daan 2019-08-11 08:59:38 -07:00
commit 3a171624bd
1 changed files with 28 additions and 38 deletions
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src/memory.c
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@ -126,7 +126,8 @@ Commit from a region
// Returns `false` on an error (OOM); `true` otherwise. `p` and `id` are only written
// if the blocks were successfully claimed so ensure they are initialized to NULL/SIZE_MAX before the call.
// (not being able to claim is not considered an error so check for `p != NULL` afterwards).
static bool mi_region_commit_blocks(mem_region_t* region, size_t idx, size_t bitidx, size_t blocks, size_t size, bool commit, void** p, size_t* id, mi_os_tld_t* tld) {
static bool mi_region_commit_blocks(mem_region_t* region, size_t idx, size_t bitidx, size_t blocks, size_t size, bool commit, void** p, size_t* id, mi_os_tld_t* tld)
{
size_t mask = mi_region_block_mask(blocks,bitidx);
mi_assert_internal(mask != 0);
mi_assert_internal((mask & mi_atomic_read(&region->map)) == mask);
@ -189,47 +190,35 @@ static bool mi_region_commit_blocks(mem_region_t* region, size_t idx, size_t bit
// Returns `false` on an error (OOM); `true` otherwise. `p` and `id` are only written
// if the blocks were successfully claimed so ensure they are initialized to NULL/SIZE_MAX before the call.
// (not being able to claim is not considered an error so check for `p != NULL` afterwards).
static bool mi_region_alloc_blocks(mem_region_t* region, size_t idx, size_t blocks, size_t size, bool commit, void** p, size_t* id, mi_os_tld_t* tld) {
static bool mi_region_alloc_blocks(mem_region_t* region, size_t idx, size_t blocks, size_t size, bool commit, void** p, size_t* id, mi_os_tld_t* tld)
{
mi_assert_internal(p != NULL && id != NULL);
mi_assert_internal(blocks < MI_REGION_MAP_BITS);
const uintptr_t mask = mi_region_block_mask(blocks,0);
const size_t bitidx_max = MI_REGION_MAP_BITS - blocks;
size_t bitidx ;
uintptr_t map;
uintptr_t newmap;
do { // while no atomic claim success and not all bits seen
// find the first free range of bits
map = mi_atomic_read(&region->map);
size_t m = map;
bitidx = 0;
do {
// skip ones
while ((m&1) != 0) { bitidx++; m>>=1; }
// count zeros
mi_assert_internal((m&1)==0);
size_t zeros = 1;
m >>= 1;
while(zeros < blocks && (m&1)==0) { zeros++; m>>=1; }
if (zeros == blocks) break; // found a range that fits
bitidx += zeros;
}
while(bitidx <= bitidx_max);
if (bitidx > bitidx_max) {
return true; // no error, but could not find a range either
}
// try to claim it
mi_assert_internal( (mask << bitidx) >> bitidx == mask ); // no overflow?
mi_assert_internal( (map & (mask << bitidx)) == 0); // fits in zero range
newmap = map | (mask << bitidx);
mi_assert_internal((newmap^map) >> bitidx == mask);
// scan linearly for a free range of zero bits
uintptr_t map = mi_atomic_read(&region->map);
uintptr_t m = mask; // the mask shifted by bitidx
for(size_t bitidx = 0; bitidx <= bitidx_max; bitidx++, m <<= 1) {
if ((map & m) == 0) { // are the mask bits free at bitidx?
mi_assert_internal((m >> bitidx) == mask); // no overflow?
uintptr_t newmap = map | m;
mi_assert_internal((newmap^map) >> bitidx == mask);
if (!mi_atomic_compare_exchange(&region->map, newmap, map)) {
// no success, another thread claimed concurrently.. keep going
map = mi_atomic_read(&region->map);
}
else {
// success, we claimed the bits
// now commit the block memory -- this can still fail
return mi_region_commit_blocks(region, idx, bitidx, blocks, size, commit, p, id, tld);
}
}
}
while(!mi_atomic_compare_exchange(&region->map, newmap, map));
// success, we claimed the blocks atomically
// now commit the block memory -- this can still fail
return mi_region_commit_blocks(region, idx, bitidx, blocks, size, commit, p, id, tld);
// no error, but also no bits found
return true;
}
// Try to allocate `blocks` in a `region` at `idx` of a given `size`. Does a quick check before trying to claim.
@ -280,13 +269,14 @@ void* _mi_mem_alloc_aligned(size_t size, size_t alignment, bool commit, size_t*
size_t count = mi_atomic_read(&regions_count);
size_t idx = mi_atomic_read(&region_next_idx);
for (size_t visited = 0; visited < count; visited++, idx++) {
if (!mi_region_try_alloc_blocks(idx%count, blocks, size, commit, &p, id, tld)) return NULL; // error
if (idx >= count) idx = 0; // wrap around
if (!mi_region_try_alloc_blocks(idx, blocks, size, commit, &p, id, tld)) return NULL; // error
if (p != NULL) break;
}
if (p == NULL) {
// no free range in existing regions -- try to extend beyond the count
for (idx = count; idx < MI_REGION_MAX; idx++) {
// no free range in existing regions -- try to extend beyond the count.. but at most 4 regions
for (idx = count; idx < count + 4 && idx < MI_REGION_MAX; idx++) {
if (!mi_region_try_alloc_blocks(idx, blocks, size, commit, &p, id, tld)) return NULL; // error
if (p != NULL) break;
}