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PR#66 by kickunderscore to ensure consistent small block alignment

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This commit is contained in:
daan 2019-07-02 08:46:50 -07:00
parent d6901558cd
commit d35fc6cdc4
4 changed files with 23 additions and 13 deletions
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25
src/segment.c
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@ -121,16 +121,25 @@ static void mi_segment_queue_insert_before(mi_segment_queue_t* queue, mi_segment
}
// Start of the page available memory
uint8_t* _mi_segment_page_start(const mi_segment_t* segment, const mi_page_t* page, size_t* page_size)
// Start of the page available memory; can be used on uninitialized pages (only `segment_idx` must be set)
uint8_t* _mi_segment_page_start(const mi_segment_t* segment, const mi_page_t* page, size_t block_size, size_t* page_size)
{
size_t psize = (segment->page_kind == MI_PAGE_HUGE ? segment->segment_size : (size_t)1 << segment->page_shift);
uint8_t* p = (uint8_t*)segment + page->segment_idx*psize;
if (page->segment_idx == 0) {
// the first page starts after the segment info (and possible guard page)
p += segment->segment_info_size;
psize -= segment->segment_info_size;
// the first page starts after the segment info (and possible guard page)
p += segment->segment_info_size;
psize -= segment->segment_info_size;
// for small objects, ensure the page start is aligned with the block size (PR#66 by kickunderscore)
if (block_size > 0 && segment->page_kind == MI_PAGE_SMALL) {
size_t adjust = block_size - ((uintptr_t)p % block_size);
if (adjust < block_size) {
p += adjust;
psize -= adjust;
}
mi_assert_internal((uintptr_t)p % block_size == 0);
}
}
long secure = mi_option_get(mi_option_secure);
if (secure > 1 || (secure == 1 && page->segment_idx == segment->capacity - 1)) {
@ -138,7 +147,7 @@ uint8_t* _mi_segment_page_start(const mi_segment_t* segment, const mi_page_t* pa
// secure > 1: every page has an os guard page
psize -= _mi_os_page_size();
}
if (page_size != NULL) *page_size = psize;
mi_assert_internal(_mi_ptr_page(p) == page);
mi_assert_internal(_mi_ptr_segment(p) == segment);
@ -381,7 +390,7 @@ static mi_segment_t* mi_segment_alloc( size_t required, mi_page_kind_t page_kind
// Available memory in a page
static size_t mi_page_size(const mi_page_t* page) {
size_t psize;
_mi_segment_page_start(_mi_page_segment(page), page, &psize);
_mi_page_start(_mi_page_segment(page), page, &psize);
return psize;
}
#endif
@ -467,7 +476,7 @@ static void mi_segment_page_clear(mi_segment_t* segment, mi_page_t* page, mi_sta
// reset the page memory to reduce memory pressure?
if (!page->is_reset && mi_option_is_enabled(mi_option_page_reset)) {
size_t psize;
uint8_t* start = _mi_segment_page_start(segment, page, &psize);
uint8_t* start = _mi_page_start(segment, page, &psize);
mi_stat_increase( stats->reset, psize); // for stats we assume resetting the full page
page->is_reset = true;
if (inuse > 0) {