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Set/clear CHUNK_MAP_ZEROED in arena_chunk_purge().

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Properly set/clear CHUNK_MAP_ZEROED for all purged pages, according to
whether the pages are (potentially) file-backed or anonymous.  This was
merely a performance pessimization for the anonymous mapping case, but
was a calloc()-related bug for the swap_enabled case.
This commit is contained in:
Jason Evans 2010-03-22 11:45:01 -07:00
parent 19b3d61892
commit c03a63d68d
1 changed files with 32 additions and 11 deletions
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43
jemalloc/src/arena.c
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@ -593,7 +593,7 @@ 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;
size_t pageind, flag_zeroed;
#ifdef JEMALLOC_DEBUG
size_t ndirty;
#endif
@ -603,6 +603,12 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
ql_new(&mapelms);
flag_zeroed =
#ifdef JEMALLOC_SWAP
swap_enabled ? 0 :
#endif
CHUNK_MAP_ZEROED;
/*
* If chunk is the spare, temporarily re-allocate it, 1) so that its
* run is reinserted into runs_avail_dirty, and 2) so that it cannot be
@ -633,17 +639,32 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
npages = mapelm->bits >> PAGE_SHIFT;
assert(pageind + npages <= chunk_npages);
if (mapelm->bits & CHUNK_MAP_DIRTY) {
/*
* Dirty run; temporarily allocate it. Set the
* last map element first, in case this is a
* one-page run.
*/
size_t i;
arena_avail_tree_remove(
&arena->runs_avail_dirty, mapelm);
chunk->map[pageind + npages - 1].bits =
(CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED);
/*
* Update internal elements in the page map, so
* that CHUNK_MAP_ZEROED is properly set.
* madvise(..., MADV_DONTNEED) results in
* zero-filled pages for anonymous mappings,
* but not for file-backed mappings.
*/
mapelm->bits = (npages << PAGE_SHIFT) |
CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED;
CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED |
flag_zeroed;
for (i = 1; i < npages - 1; i++) {
chunk->map[pageind + i].bits =
flag_zeroed;
}
if (npages > 1) {
chunk->map[pageind + npages - 1].bits =
(npages << PAGE_SHIFT) |
CHUNK_MAP_LARGE | CHUNK_MAP_ALLOCATED |
flag_zeroed;
}
arena->nactive += npages;
/* Append to list for later processing. */
ql_elm_new(mapelm, u.ql_link);
@ -653,9 +674,9 @@ arena_chunk_purge(arena_t *arena, arena_chunk_t *chunk)
pageind += npages;
} else {
/* Skip allocated run. */
if (mapelm->bits & CHUNK_MAP_LARGE) {
if (mapelm->bits & CHUNK_MAP_LARGE)
pageind += mapelm->bits >> PAGE_SHIFT;
} else {
else {
arena_run_t *run = (arena_run_t *)((uintptr_t)
chunk + (uintptr_t)(pageind << PAGE_SHIFT));