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refactor in-place expansion

This commit is contained in:
Daan 2024-05-11 10:07:15 -07:00
parent 8b8e689b91
commit 3b057c08b4
3 changed files with 60 additions and 38 deletions
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88
src/os.c
View File

@ -403,6 +403,11 @@ void* _mi_os_alloc_aligned_at_offset(size_t size, size_t alignment, size_t offse
----------------------------------------------------------- */
void* _mi_os_alloc_expandable(size_t size, size_t alignment, size_t future_reserve, mi_memid_t* memid, mi_stats_t* stats) {
if (!mi_os_mem_config.has_virtual_reserve) {
// don't allocate expandable if the OS does not support virtual reservation
return _mi_os_alloc_aligned(size, alignment, false, false, memid, stats);
}
size = mi_os_get_alloc_size(size);
if (future_reserve < 2*size) { future_reserve = 2*size; }
void* p = _mi_os_alloc_aligned(future_reserve, alignment, false, false, memid, stats);
@ -415,9 +420,56 @@ void* _mi_os_alloc_expandable(size_t size, size_t alignment, size_t future_reser
return p;
}
static bool mi_os_try_expand_inplace( void* p, size_t size, size_t newsize, mi_memid_t* memid, mi_stats_t* stats) {
// try to expand the existing virtual range "in-place"
if (p != NULL && size > 0 && newsize > size &&
!mi_os_mem_config.must_free_whole && !memid->is_pinned && memid->mem.os.prim_info == NULL)
{
void* expand = (uint8_t*)p + size;
size_t extra = newsize - size;
mi_assert_internal(extra > 0 && (extra % _mi_os_page_size()) == 0);
bool os_is_large = false;
bool os_is_zero = false;
void* newp = mi_os_prim_alloc_at(expand, extra, 1, false /* commit? */, false /* allow large */, &os_is_large, &os_is_zero, stats);
if (newp == expand) {
// success! we expanded the virtual address space in-place
if (_mi_os_commit(newp, extra, &os_is_zero, stats)) {
_mi_verbose_message("expanded in place (address: %p, from %zu bytes to %zu bytes\n", p, size, newsize);
memid->is_pinned = os_is_large;
memid->mem.os.size += extra;
return true;
}
}
// failed, free reserved space
if (newp != NULL) {
mi_os_prim_free(newp, extra, false, stats);
}
return false;
}
else if (p != NULL && newsize > 0 && newsize < size &&
!mi_os_mem_config.must_free_whole && !memid->is_pinned && memid->mem.os.prim_info == NULL)
{
// we can shrink in-place by free-ing the upper part
void* shrink = (uint8_t*)p + newsize;
size_t extra = size - newsize;
mi_assert_internal(extra > 0 && (extra % _mi_os_page_size()) == 0);
mi_os_prim_free(shrink, extra, true, stats);
_mi_verbose_message("shrunk OS memory in place (address: %p, from %zu bytes to %zu bytes\n", p, size, newsize);
memid->mem.os.size -= extra;
return true;
}
else {
return false;
}
}
bool _mi_os_expand(void* p, size_t size, size_t newsize, mi_memid_t* memid, mi_stats_t* stats) {
if (p == NULL) return false;
if (memid->memkind != MI_MEM_OS_EXPAND) return false;
if (memid->memkind != MI_MEM_OS_EXPAND) {
return mi_os_try_expand_inplace(p,size,newsize,memid,stats);
}
// expandable memory
if (newsize > size) {
if (memid->mem.os.size < newsize) {
return false;
@ -456,39 +508,7 @@ static void* mi_os_remap_copy(void* p, size_t size, size_t newsize, size_t align
newsize = mi_os_get_alloc_size(newsize);
// first try to expand the existing virtual range "in-place"
if (p != NULL && size > 0 && newsize > size &&
!mi_os_mem_config.must_free_whole && !memid->is_pinned && memid->mem.os.prim_info == NULL)
{
void* expand = (uint8_t*)p + size;
size_t extra = newsize - size;
mi_assert_internal(extra > 0 && (extra % _mi_os_page_size()) == 0);
bool os_is_large = false;
bool os_is_zero = false;
void* newp = mi_os_prim_alloc_at(expand, extra, 1, false /* commit? */, false, &os_is_large, &os_is_zero, stats);
if (newp == expand) {
// success! we expanded the virtual address space in-place
if (_mi_os_commit(newp, extra, &os_is_zero, stats)) {
_mi_verbose_message("expanded in place (address: %p, from %zu bytes to %zu bytes\n", p, size, newsize);
memid->is_pinned = os_is_large;
memid->mem.os.size += newsize;
return p;
}
}
// failed, free reserved space and fall back to a copy
if (newp != NULL) {
mi_os_prim_free(newp, extra, false, stats);
}
}
else if (p != NULL && newsize > 0 && newsize < size &&
!mi_os_mem_config.must_free_whole && !memid->is_pinned && memid->mem.os.prim_info == NULL)
{
// we can shrink in-place by free-ing the upper part
void* shrink = (uint8_t*)p + newsize;
size_t extra = size - newsize;
mi_assert_internal(extra > 0 && (extra % _mi_os_page_size()) == 0);
mi_os_prim_free(shrink, extra, true, stats);
_mi_verbose_message("shrunk OS memory in place (address: %p, from %zu bytes to %zu bytes\n", p, size, newsize);
if (mi_os_try_expand_inplace(p,size,newsize,memid,stats)) {
return p;
}

5
src/prim/emscripten/prim.c
View File

@ -53,6 +53,7 @@ void _mi_prim_mem_init( mi_os_mem_config_t* config) {
config->has_overcommit = false;
config->must_free_whole = true;
config->has_virtual_reserve = false;
config->has_remap = false;
}
extern void emmalloc_free(void*);
@ -71,8 +72,8 @@ int _mi_prim_free(void* addr, size_t size) {
extern void* emmalloc_memalign(size_t alignment, size_t size);
// Note: the `try_alignment` is just a hint and the returned pointer is not guaranteed to be aligned.
int _mi_prim_alloc(size_t size, size_t try_alignment, bool commit, bool allow_large, bool* is_large, bool* is_zero, void** addr) {
MI_UNUSED(try_alignment); MI_UNUSED(allow_large); MI_UNUSED(commit);
int _mi_prim_alloc(void* hint, size_t size, size_t try_alignment, bool commit, bool allow_large, bool* is_large, bool* is_zero, void** addr) {
MI_UNUSED(hint); MI_UNUSED(allow_large); MI_UNUSED(commit);
*is_large = false;
// TODO: Track the highest address ever seen; first uses of it are zeroes.
// That assumes no one else uses sbrk but us (they could go up,

1
src/prim/windows/prim.c
View File

@ -113,6 +113,7 @@ void _mi_prim_mem_init( mi_os_mem_config_t* config )
config->has_overcommit = false;
config->must_free_whole = true;
config->has_virtual_reserve = true;
config->has_remap = false;
// get the page size
SYSTEM_INFO si;
GetSystemInfo(&si);