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bring inline with C11 atomics; no volatile and cas order of expected/desired

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daan 2020-07-25 22:52:27 -07:00
parent e27422adca
commit 09ade02429
12 changed files with 170 additions and 188 deletions
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19
src/os.c
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@ -266,7 +266,7 @@ static void* mi_win_virtual_allocx(void* addr, size_t size, size_t try_alignment
static void* mi_win_virtual_alloc(void* addr, size_t size, size_t try_alignment, DWORD flags, bool large_only, bool allow_large, bool* is_large) {
mi_assert_internal(!(large_only && !allow_large));
static volatile _Atomic(uintptr_t) large_page_try_ok; // = 0;
static _Atomic(uintptr_t) large_page_try_ok; // = 0;
void* p = NULL;
if ((large_only || use_large_os_page(size, try_alignment))
&& allow_large && (flags&MEM_COMMIT)!=0 && (flags&MEM_RESERVE)!=0) {
@ -274,7 +274,7 @@ static void* mi_win_virtual_alloc(void* addr, size_t size, size_t try_alignment,
if (!large_only && try_ok > 0) {
// if a large page allocation fails, it seems the calls to VirtualAlloc get very expensive.
// therefore, once a large page allocation failed, we don't try again for `large_page_try_ok` times.
mi_atomic_cas_weak(&large_page_try_ok, try_ok - 1, try_ok);
mi_atomic_cas_strong(&large_page_try_ok, &try_ok, try_ok - 1);
}
else {
// large OS pages must always reserve and commit.
@ -360,14 +360,14 @@ static void* mi_unix_mmap(void* addr, size_t size, size_t try_alignment, int pro
fd = VM_MAKE_TAG(os_tag);
#endif
if ((large_only || use_large_os_page(size, try_alignment)) && allow_large) {
static volatile _Atomic(uintptr_t) large_page_try_ok; // = 0;
static _Atomic(uintptr_t) large_page_try_ok; // = 0;
uintptr_t try_ok = mi_atomic_read(&large_page_try_ok);
if (!large_only && try_ok > 0) {
// If the OS is not configured for large OS pages, or the user does not have
// enough permission, the `mmap` will always fail (but it might also fail for other reasons).
// Therefore, once a large page allocation failed, we don't try again for `large_page_try_ok` times
// to avoid too many failing calls to mmap.
mi_atomic_cas_weak(&large_page_try_ok, try_ok - 1, try_ok);
mi_atomic_cas_strong(&large_page_try_ok, &try_ok, try_ok - 1);
}
else {
int lflags = flags & ~MAP_NORESERVE; // using NORESERVE on huge pages seems to fail on Linux
@ -449,7 +449,7 @@ static void* mi_unix_mmap(void* addr, size_t size, size_t try_alignment, int pro
// On 64-bit systems, we can do efficient aligned allocation by using
// the 4TiB to 30TiB area to allocate them.
#if (MI_INTPTR_SIZE >= 8) && (defined(_WIN32) || (defined(MI_OS_USE_MMAP) && !defined(MAP_ALIGNED)))
static volatile mi_decl_cache_align _Atomic(uintptr_t) aligned_base;
static mi_decl_cache_align _Atomic(uintptr_t) aligned_base;
// Return a 4MiB aligned address that is probably available
static void* mi_os_get_aligned_hint(size_t try_alignment, size_t size) {
@ -462,7 +462,8 @@ static void* mi_os_get_aligned_hint(size_t try_alignment, size_t size) {
uintptr_t r = _mi_heap_random_next(mi_get_default_heap());
init = init + (MI_SEGMENT_SIZE * ((r>>17) & 0xFFFFF)); // (randomly 20 bits)*4MiB == 0 to 4TiB
#endif
mi_atomic_cas_strong(&aligned_base, init, hint + size);
uintptr_t expected = hint + size;
mi_atomic_cas_strong(&aligned_base, &expected, init);
hint = mi_atomic_add(&aligned_base, size); // this may still give 0 or > 30TiB but that is ok, it is a hint after all
}
if (hint%try_alignment != 0) return NULL;
@ -969,9 +970,9 @@ static uint8_t* mi_os_claim_huge_pages(size_t pages, size_t* total_size) {
uintptr_t start = 0;
uintptr_t end = 0;
uintptr_t expected;
uintptr_t huge_start = mi_atomic_read_relaxed(&mi_huge_start);
do {
start = expected = mi_atomic_read_relaxed(&mi_huge_start);
start = huge_start;
if (start == 0) {
// Initialize the start address after the 32TiB area
start = ((uintptr_t)32 << 40); // 32TiB virtual start address
@ -982,7 +983,7 @@ static uint8_t* mi_os_claim_huge_pages(size_t pages, size_t* total_size) {
}
end = start + size;
mi_assert_internal(end % MI_SEGMENT_SIZE == 0);
} while (!mi_atomic_cas_strong(&mi_huge_start, end, expected));
} while (!mi_atomic_cas_strong(&mi_huge_start, &huge_start, end));
if (total_size != NULL) *total_size = size;
return (uint8_t*)start;