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experimental eager page commit option

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This commit is contained in:
daan 2019-11-24 22:00:11 -08:00
parent 4452431b6c
commit c6df7a199c
5 changed files with 57 additions and 38 deletions
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1
include/mimalloc.h
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@ -267,6 +267,7 @@ typedef enum mi_option_e {
// the following options are experimental
mi_option_eager_commit,
mi_option_eager_region_commit,
mi_option_eager_page_commit,
mi_option_large_os_pages, // implies eager commit
mi_option_reserve_huge_os_pages,
mi_option_segment_cache,

5
src/options.c
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@ -56,18 +56,19 @@ static mi_option_desc_t options[_mi_option_last] =
{ 0, UNINIT, MI_OPTION(verbose) },
// the following options are experimental and not all combinations make sense.
{ 1, UNINIT, MI_OPTION(eager_commit) }, // note: needs to be on when eager_region_commit is enabled
{ 0, UNINIT, MI_OPTION(eager_commit) }, // note: needs to be on when eager_region_commit is enabled
#ifdef _WIN32 // and BSD?
{ 0, UNINIT, MI_OPTION(eager_region_commit) }, // don't commit too eagerly on windows (just for looks...)
#else
{ 1, UNINIT, MI_OPTION(eager_region_commit) },
#endif
{ 1, UNINIT, MI_OPTION(eager_page_commit) },
{ 0, UNINIT, MI_OPTION(large_os_pages) }, // use large OS pages, use only with eager commit to prevent fragmentation of VMA's
{ 0, UNINIT, MI_OPTION(reserve_huge_os_pages) },
{ 0, UNINIT, MI_OPTION(segment_cache) }, // cache N segments per thread
{ 0, UNINIT, MI_OPTION(page_reset) }, // reset pages on free
{ 0, UNINIT, MI_OPTION(segment_reset) }, // reset segment memory on free (needs eager commit)
{ 1, UNINIT, MI_OPTION(reset_decommits) }, // reset decommits memory
{ 0, UNINIT, MI_OPTION(reset_decommits) }, // reset decommits memory
{ 0, UNINIT, MI_OPTION(eager_commit_delay) }, // the first N segments per thread are not eagerly committed
{ 500, UNINIT, MI_OPTION(reset_delay) }, // reset delay in milli-seconds
{ 0, UNINIT, MI_OPTION(use_numa_nodes) }, // 0 = use available numa nodes, otherwise use at most N nodes.

2
src/os.c
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@ -603,7 +603,7 @@ static void* mi_os_page_align_area_conservative(void* addr, size_t size, size_t*
// (but not for the reset version where we want commit to be conservative as well)
static bool mi_os_commitx(void* addr, size_t size, bool commit, bool conservative, bool* is_zero, mi_stats_t* stats) {
// page align in the range, commit liberally, decommit conservative
*is_zero = false;
if (is_zero != NULL) { *is_zero = false; }
size_t csize;
void* start = mi_os_page_align_areax(conservative, addr, size, &csize);
if (csize == 0) return true; // || _mi_os_is_huge_reserved(addr))

31
src/page.c
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@ -35,7 +35,7 @@ static inline mi_block_t* mi_page_block_at(const mi_page_t* page, void* page_sta
return (mi_block_t*)((uint8_t*)page_start + (i * page->block_size));
}
static void mi_page_init(mi_heap_t* heap, mi_page_t* page, size_t size, mi_stats_t* stats);
static void mi_page_init(mi_heap_t* heap, mi_page_t* page, size_t size, mi_tld_t* tld);
#if (MI_DEBUG>=3)
@ -242,7 +242,7 @@ static mi_page_t* mi_page_fresh_alloc(mi_heap_t* heap, mi_page_queue_t* pq, size
mi_page_t* page = _mi_segment_page_alloc(block_size, &heap->tld->segments, &heap->tld->os);
if (page == NULL) return NULL;
mi_assert_internal(pq==NULL || _mi_page_segment(page)->page_kind != MI_PAGE_HUGE);
mi_page_init(heap, page, block_size, &heap->tld->stats);
mi_page_init(heap, page, block_size, heap->tld);
_mi_stat_increase( &heap->tld->stats.pages, 1);
if (pq!=NULL) mi_page_queue_push(heap, pq, page); // huge pages use pq==NULL
mi_assert_expensive(_mi_page_is_valid(page));
@ -544,8 +544,7 @@ static mi_decl_noinline void mi_page_free_list_extend( mi_page_t* const page, co
// Note: we also experimented with "bump" allocation on the first
// allocations but this did not speed up any benchmark (due to an
// extra test in malloc? or cache effects?)
static void mi_page_extend_free(mi_heap_t* heap, mi_page_t* page, mi_stats_t* stats) {
UNUSED(stats);
static void mi_page_extend_free(mi_heap_t* heap, mi_page_t* page, mi_tld_t* tld) {
mi_assert_expensive(mi_page_is_valid_init(page));
#if (MI_SECURE<=2)
mi_assert(page->free == NULL);
@ -555,8 +554,8 @@ static void mi_page_extend_free(mi_heap_t* heap, mi_page_t* page, mi_stats_t* st
if (page->capacity >= page->reserved) return;
size_t page_size;
_mi_page_start(_mi_page_segment(page), page, &page_size);
mi_stat_counter_increase(stats->pages_extended, 1);
uint8_t* page_start = _mi_page_start(_mi_page_segment(page), page, &page_size);
mi_stat_counter_increase(tld->stats.pages_extended, 1);
// calculate the extend count
size_t extend = page->reserved - page->capacity;
@ -572,16 +571,22 @@ static void mi_page_extend_free(mi_heap_t* heap, mi_page_t* page, mi_stats_t* st
mi_assert_internal(extend > 0 && extend + page->capacity <= page->reserved);
mi_assert_internal(extend < (1UL<<16));
// commit on-demand for large and huge pages?
if (_mi_page_segment(page)->page_kind >= MI_PAGE_LARGE && !mi_option_is_enabled(mi_option_eager_page_commit)) {
uint8_t* start = page_start + (page->capacity * page->block_size);
_mi_mem_commit(start, extend * page->block_size, NULL, &tld->os);
}
// and append the extend the free list
if (extend < MI_MIN_SLICES || MI_SECURE==0) { //!mi_option_is_enabled(mi_option_secure)) {
mi_page_free_list_extend(page, extend, stats );
mi_page_free_list_extend(page, extend, &tld->stats );
}
else {
mi_page_free_list_extend_secure(heap, page, extend, stats);
mi_page_free_list_extend_secure(heap, page, extend, &tld->stats);
}
// enable the new free list
page->capacity += (uint16_t)extend;
mi_stat_increase(stats->page_committed, extend * page->block_size);
mi_stat_increase(tld->stats.page_committed, extend * page->block_size);
// extension into zero initialized memory preserves the zero'd free list
if (!page->is_zero_init) {
@ -591,7 +596,7 @@ static void mi_page_extend_free(mi_heap_t* heap, mi_page_t* page, mi_stats_t* st
}
// Initialize a fresh page
static void mi_page_init(mi_heap_t* heap, mi_page_t* page, size_t block_size, mi_stats_t* stats) {
static void mi_page_init(mi_heap_t* heap, mi_page_t* page, size_t block_size, mi_tld_t* tld) {
mi_assert(page != NULL);
mi_segment_t* segment = _mi_page_segment(page);
mi_assert(segment != NULL);
@ -621,7 +626,7 @@ static void mi_page_init(mi_heap_t* heap, mi_page_t* page, size_t block_size, mi
mi_assert_expensive(mi_page_is_valid_init(page));
// initialize an initial free list
mi_page_extend_free(heap,page,stats);
mi_page_extend_free(heap,page,tld);
mi_assert(mi_page_immediate_available(page));
}
@ -666,7 +671,7 @@ static mi_page_t* mi_page_queue_find_free_ex(mi_heap_t* heap, mi_page_queue_t* p
// 2. Try to extend
if (page->capacity < page->reserved) {
mi_page_extend_free(heap, page, &heap->tld->stats);
mi_page_extend_free(heap, page, heap->tld);
mi_assert_internal(mi_page_immediate_available(page));
break;
}
@ -707,7 +712,7 @@ static inline mi_page_t* mi_find_free_page(mi_heap_t* heap, size_t size) {
if (page != NULL) {
if ((MI_SECURE >= 3) && page->capacity < page->reserved && ((_mi_heap_random(heap) & 1) == 1)) {
// in secure mode, we extend half the time to increase randomness
mi_page_extend_free(heap, page, &heap->tld->stats);
mi_page_extend_free(heap, page, heap->tld);
mi_assert_internal(mi_page_immediate_available(page));
}
else {

56
src/segment.c
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@ -200,7 +200,12 @@ static void mi_page_reset(mi_segment_t* segment, mi_page_t* page, size_t size, m
void* start = mi_segment_raw_page_start(segment, page, &psize);
page->is_reset = true;
mi_assert_internal(size <= psize);
_mi_mem_reset(start, ((size == 0 || size > psize) ? psize : size), tld->os);
size_t reset_size = (size == 0 || size > psize ? psize : size);
if (size == 0 && segment->page_kind >= MI_PAGE_LARGE && !mi_option_is_enabled(mi_option_eager_page_commit)) {
mi_assert_internal(page->block_size > 0);
reset_size = page->capacity * page->block_size;
}
_mi_mem_reset(start, reset_size, tld->os);
}
static void mi_page_unreset(mi_segment_t* segment, mi_page_t* page, size_t size, mi_segments_tld_t* tld)
@ -210,8 +215,13 @@ static void mi_page_unreset(mi_segment_t* segment, mi_page_t* page, size_t size,
page->is_reset = false;
size_t psize;
uint8_t* start = mi_segment_raw_page_start(segment, page, &psize);
size_t unreset_size = (size == 0 || size > psize ? psize : size);
if (size == 0 && segment->page_kind >= MI_PAGE_LARGE && !mi_option_is_enabled(mi_option_eager_page_commit)) {
mi_assert_internal(page->block_size > 0);
unreset_size = page->capacity * page->block_size;
}
bool is_zero = false;
_mi_mem_unreset(start, ((size == 0 || size > psize) ? psize : size), &is_zero, tld->os);
_mi_mem_unreset(start, unreset_size, &is_zero, tld->os);
if (is_zero) page->is_zero_init = true;
}
@ -414,8 +424,7 @@ static mi_segment_t* mi_segment_alloc(size_t required, mi_page_kind_t page_kind,
size_t pre_size;
size_t segment_size = mi_segment_size(capacity, required, &pre_size, &info_size);
mi_assert_internal(segment_size >= required);
size_t page_size = (page_kind == MI_PAGE_HUGE ? segment_size : (size_t)1 << page_shift);
// Initialize parameters
bool eager_delayed = (page_kind <= MI_PAGE_MEDIUM && tld->count < (size_t)mi_option_get(mi_option_eager_commit_delay));
bool eager = !eager_delayed && mi_option_is_enabled(mi_option_eager_commit);
@ -554,14 +563,16 @@ static mi_page_t* mi_segment_find_free(mi_segment_t* segment, mi_segments_tld_t*
if (!page->is_committed) {
mi_assert_internal(!segment->mem_is_fixed);
mi_assert_internal(!page->is_reset);
size_t psize;
uint8_t* start = mi_segment_raw_page_start(segment, page, &psize);
page->is_committed = true;
bool is_zero = false;
const size_t gsize = (MI_SECURE >= 2 ? _mi_os_page_size() : 0);
_mi_mem_commit(start,psize + gsize,&is_zero,tld->os);
if (gsize > 0) { mi_segment_protect_range(start + psize, gsize, true); }
if (is_zero) { page->is_zero_init = true; }
if (segment->page_kind < MI_PAGE_LARGE || mi_option_is_enabled(mi_option_eager_page_commit)) {
page->is_committed = true;
size_t psize;
uint8_t* start = mi_segment_raw_page_start(segment, page, &psize);
bool is_zero = false;
const size_t gsize = (MI_SECURE >= 2 ? _mi_os_page_size() : 0);
_mi_mem_commit(start, psize + gsize, &is_zero, tld->os);
if (gsize > 0) { mi_segment_protect_range(start + psize, gsize, true); }
if (is_zero) { page->is_zero_init = true; }
}
}
if (page->is_reset) {
mi_page_unreset(segment, page, 0, tld); // todo: only unreset the part that was reset?
@ -583,26 +594,27 @@ static void mi_segment_abandon(mi_segment_t* segment, mi_segments_tld_t* tld);
static void mi_segment_page_clear(mi_segment_t* segment, mi_page_t* page, mi_segments_tld_t* tld) {
mi_assert_internal(page->segment_in_use);
mi_assert_internal(mi_page_all_free(page));
mi_assert_internal(page->is_committed);
mi_assert_internal(segment->page_kind >= MI_PAGE_LARGE || page->is_committed);
size_t inuse = page->capacity * page->block_size;
_mi_stat_decrease(&tld->stats->page_committed, inuse);
_mi_stat_decrease(&tld->stats->pages, 1);
// calculate the used size from the raw (non-aligned) start of the page
size_t pre_size;
_mi_segment_page_start(segment, page, page->block_size, NULL, &pre_size);
size_t used_size = pre_size + (page->capacity * page->block_size);
//size_t pre_size;
//_mi_segment_page_start(segment, page, page->block_size, NULL, &pre_size);
//size_t used_size = pre_size + (page->capacity * page->block_size);
// zero the page data, but not the segment fields
page->is_zero_init = false;
ptrdiff_t ofs = offsetof(mi_page_t,capacity);
memset((uint8_t*)page + ofs, 0, sizeof(*page) - ofs);
page->segment_in_use = false;
segment->used--;
// reset the page memory to reduce memory pressure?
// note: must come after setting `segment_in_use` to false
// note: must come after setting `segment_in_use` to false but before block_size becomes 0
mi_page_reset(segment, page, 0 /*used_size*/, tld);
// zero the page data, but not the segment fields
ptrdiff_t ofs = offsetof(mi_page_t,capacity);
memset((uint8_t*)page + ofs, 0, sizeof(*page) - ofs);
segment->used--;
}
void _mi_segment_page_free(mi_page_t* page, bool force, mi_segments_tld_t* tld)
@ -713,7 +725,7 @@ bool _mi_segment_try_reclaim_abandoned( mi_heap_t* heap, bool try_all, mi_segmen
mi_page_t* page = &segment->pages[i];
if (page->segment_in_use) {
mi_assert_internal(!page->is_reset);
mi_assert_internal(page->is_committed);
mi_assert_internal(segment->page_kind >= MI_PAGE_LARGE || page->is_committed);
segment->abandoned--;
mi_assert(page->next == NULL);
_mi_stat_decrease(&tld->stats->pages_abandoned, 1);