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improve allocation of the huge OS page arena

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daan 2019-10-31 19:39:49 -07:00
parent d36d04b4a6
commit aaf01620f4
2 changed files with 60 additions and 89 deletions
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39
src/arena.c
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@ -6,7 +6,16 @@ terms of the MIT license. A copy of the license can be found in the file
-----------------------------------------------------------------------------*/
/* ----------------------------------------------------------------------------
"Arenas" are fixed area's of OS memory from which we can allocate
large blocks (>= MI_ARENA_BLOCK_SIZE, 16MiB). Currently only used to
allocate in one arena consisting of huge OS pages -- otherwise it
delegates to direct allocation from the OS.
In the future, we can expose an API to manually add more arenas which
is sometimes needed for embedded devices or shared memory for example.
The arena allocation needs to be thread safe and we use a lock-free scan
with on-demand coalescing.
-----------------------------------------------------------------------------*/
#include "mimalloc.h"
#include "mimalloc-internal.h"
@ -16,8 +25,8 @@ terms of the MIT license. A copy of the license can be found in the file
// os.c
void* _mi_os_alloc_aligned(size_t size, size_t alignment, bool commit, bool* large, mi_os_tld_t* tld);
void* _mi_os_try_alloc_from_huge_reserved(size_t size, size_t try_alignment);
int _mi_os_reserve_huge_os_pages(size_t pages, double max_secs, size_t* pages_reserved) mi_attr_noexcept;
int _mi_os_alloc_huge_os_pages(size_t pages, double max_secs, void** pstart, size_t* pages_reserved, size_t* psize) mi_attr_noexcept;
void _mi_os_free(void* p, size_t size, mi_stats_t* stats);
/* -----------------------------------------------------------
Arena allocation
@ -338,25 +347,27 @@ static bool mi_arena_add(mi_arena_t* arena) {
/* -----------------------------------------------------------
Reserve a huge page arena.
TODO: improve OS api to just reserve and claim a huge
page area at once, (and return the total size).
----------------------------------------------------------- */
#include <errno.h>
#include <errno.h> // ENOMEM
int mi_reserve_huge_os_pages(size_t pages, double max_secs, size_t* pages_reserved) mi_attr_noexcept {
size_t pages_reserved_default = 0;
if (pages_reserved==NULL) pages_reserved = &pages_reserved_default;
int err = _mi_os_reserve_huge_os_pages(pages, max_secs, pages_reserved);
if (*pages_reserved==0) return err;
size_t hsize = (*pages_reserved) * GiB;
void* p = _mi_os_try_alloc_from_huge_reserved(hsize, MI_SEGMENT_ALIGN);
mi_assert_internal(p != NULL);
if (p == NULL) return ENOMEM;
size_t hsize = 0;
void* p = NULL;
int err = _mi_os_alloc_huge_os_pages(pages, max_secs, &p, pages_reserved, &hsize);
_mi_verbose_message("reserved %zu huge pages\n", *pages_reserved);
if (p==NULL) return err;
// err might be != 0 but that is fine, we just got less pages.
mi_assert_internal(*pages_reserved > 0 && hsize > 0 && *pages_reserved <= pages);
size_t bcount = hsize / MI_ARENA_BLOCK_SIZE;
size_t asize = sizeof(mi_arena_t) + (bcount*sizeof(mi_block_info_t)); // one too much
mi_arena_t* arena = (mi_arena_t*)_mi_os_alloc(asize, &_mi_heap_default->tld->stats);
if (arena == NULL) return ENOMEM;
mi_arena_t* arena = (mi_arena_t*)_mi_os_alloc(asize, &_mi_stats_main);
if (arena == NULL) {
*pages_reserved = 0;
_mi_os_free(p, hsize, &_mi_stats_main);
return ENOMEM;
}
arena->block_count = bcount;
arena->start = (uint8_t*)p;
arena->block_bottom = 0;