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Change CHUNK_MAP_ZEROED to CHUNK_MAP_UNZEROED.

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Invert the chunk map bit that tracks whether a page is zeroed, so that
for zeroed arena chunks, the interior of the page map does not need to
be initialized (as it consists entirely of zero bytes).
This commit is contained in:
Jason Evans 2010-10-01 17:53:37 -07:00
parent 7393f44ff0
commit 3377ffa1f4
2 changed files with 32 additions and 26 deletions
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12
jemalloc/include/jemalloc/internal/arena.h
View File

@ -125,13 +125,13 @@ struct arena_chunk_map_s {
* x : don't care
* - : 0
* + : 1
* [DZLA] : bit set
* [dzla] : bit unset
* [DULA] : bit set
* [dula] : bit unset
*
* Unallocated (clean):
* ssssssss ssssssss ssss---- ----dz--
* xxxxxxxx xxxxxxxx xxxx---- -----Zxx
* ssssssss ssssssss ssss---- ----dZ--
* ssssssss ssssssss ssss---- ----du--
* xxxxxxxx xxxxxxxx xxxx---- -----Uxx
* ssssssss ssssssss ssss---- ----dU--
*
* Unallocated (dirty):
* ssssssss ssssssss ssss---- ----D---
@ -161,7 +161,7 @@ struct arena_chunk_map_s {
#endif
#define CHUNK_MAP_FLAGS_MASK ((size_t)0xfU)
#define CHUNK_MAP_DIRTY ((size_t)0x8U)
#define CHUNK_MAP_ZEROED ((size_t)0x4U)
#define CHUNK_MAP_UNZEROED ((size_t)0x4U)
#define CHUNK_MAP_LARGE ((size_t)0x2U)
#define CHUNK_MAP_ALLOCATED ((size_t)0x1U)
#define CHUNK_MAP_KEY CHUNK_MAP_ALLOCATED

46
jemalloc/src/arena.c
View File

@ -324,11 +324,11 @@ arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool large,
chunk->map[run_ind+need_pages-map_bias].bits =
(rem_pages << PAGE_SHIFT) |
(chunk->map[run_ind+need_pages-map_bias].bits &
CHUNK_MAP_ZEROED);
CHUNK_MAP_UNZEROED);
chunk->map[run_ind+total_pages-1-map_bias].bits =
(rem_pages << PAGE_SHIFT) |
(chunk->map[run_ind+total_pages-1-map_bias].bits &
CHUNK_MAP_ZEROED);
CHUNK_MAP_UNZEROED);
}
arena_avail_tree_insert(runs_avail,
&chunk->map[run_ind+need_pages-map_bias]);
@ -353,7 +353,7 @@ arena_run_split(arena_t *arena, arena_run_t *run, size_t size, bool large,
*/
for (i = 0; i < need_pages; i++) {
if ((chunk->map[run_ind+i-map_bias].bits
& CHUNK_MAP_ZEROED) == 0) {
& CHUNK_MAP_UNZEROED) != 0) {
memset((void *)((uintptr_t)
chunk + ((run_ind + i) <<
PAGE_SHIFT)), 0,
@ -420,7 +420,7 @@ arena_chunk_alloc(arena_t *arena)
arena_avail_tree_insert(runs_avail, &chunk->map[0]);
} else {
bool zero;
size_t zeroed;
size_t unzeroed;
zero = false;
malloc_mutex_unlock(&arena->lock);
@ -447,11 +447,17 @@ arena_chunk_alloc(arena_t *arena)
* Mark the pages as zeroed iff chunk_alloc() returned a zeroed
* chunk.
*/
zeroed = zero ? CHUNK_MAP_ZEROED : 0;
chunk->map[0].bits = arena_maxclass | zeroed;
for (i = map_bias+1; i < chunk_npages-1; i++)
chunk->map[i-map_bias].bits = zeroed;
chunk->map[i-map_bias].bits = arena_maxclass | zeroed;
unzeroed = zero ? 0 : CHUNK_MAP_UNZEROED;
chunk->map[0].bits = arena_maxclass | unzeroed;
/*
* There is no need to initialize the internal page map entries
* unless the chunk is not zeroed.
*/
if (zero == false) {
for (i = map_bias+1; i < chunk_npages-1; i++)
chunk->map[i-map_bias].bits = unzeroed;
}
chunk->map[chunk_npages-1].bits = arena_maxclass | unzeroed;
/* Insert the run into the runs_avail_clean tree. */
arena_avail_tree_insert(&arena->runs_avail_clean,
@ -593,7 +599,7 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
{
ql_head(arena_chunk_map_t) mapelms;
arena_chunk_map_t *mapelm;
size_t pageind, flag_zeroed;
size_t pageind, flag_unzeroed;
#ifdef JEMALLOC_DEBUG
size_t ndirty;
#endif
@ -603,18 +609,18 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
ql_new(&mapelms);
flag_zeroed =
flag_unzeroed =
#ifdef JEMALLOC_PURGE_MADVISE_DONTNEED
/*
* madvise(..., MADV_DONTNEED) results in zero-filled pages for anonymous
* mappings, but not for file-backed mappings.
*/
# ifdef JEMALLOC_SWAP
swap_enabled ? 0 :
swap_enabled ? CHUNK_MAP_UNZEROED :
# endif
CHUNK_MAP_ZEROED;
#else
0;
#else
CHUNK_MAP_UNZEROED;
#endif
/*
@ -653,21 +659,21 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
/*
* Update internal elements in the page map, so
* that CHUNK_MAP_ZEROED is properly set.
* that CHUNK_MAP_UNZEROED is properly set.
*/
mapelm->bits = (npages << PAGE_SHIFT) |
CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED |
flag_zeroed;
flag_unzeroed;
for (i = 1; i < npages - 1; i++) {
chunk->map[pageind+i-map_bias].bits =
flag_zeroed;
flag_unzeroed;
}
if (npages > 1) {
chunk->map[
pageind+npages-1-map_bias].bits =
(npages << PAGE_SHIFT) |
CHUNK_MAP_LARGE |
CHUNK_MAP_ALLOCATED | flag_zeroed;
CHUNK_MAP_ALLOCATED | flag_unzeroed;
}
arena->nactive += npages;
@ -890,10 +896,10 @@ arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
arena->ndirty += run_pages;
} else {
chunk->map[run_ind-map_bias].bits = size |
(chunk->map[run_ind-map_bias].bits & CHUNK_MAP_ZEROED);
(chunk->map[run_ind-map_bias].bits & CHUNK_MAP_UNZEROED);
chunk->map[run_ind+run_pages-1-map_bias].bits = size |
(chunk->map[run_ind+run_pages-1-map_bias].bits &
CHUNK_MAP_ZEROED);
CHUNK_MAP_UNZEROED);
}
/* Try to coalesce forward. */