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Split run deallocation out of arena_dalloc_bin(), into arena_dalloc_bin_run().

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Enhance bin run deallocation to avoid marking all pages as dirty, since the
dirty bits are already correct for all but the first page, due to the use of
arena_run_rc_{incr,decr}().  This tends to dramatically reduce the number of
pages that are marked dirty.

Modify arena_bin_run_size_calc() to assure that bin run headers never exceed
one page.  In practice, this can't happen unless hard-coded constants (related
to RUN_MAX_OVRHD) are modified, but the dirty page tracking code assumes bin
run headers never extend past the first page, so it seems worth making this a
universally valid assumption.
This commit is contained in:
Jason Evans 2010-01-03 12:10:47 -08:00
parent 03c2237af3
commit 952b7d192b
1 changed files with 89 additions and 47 deletions
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128
jemalloc/src/jemalloc.c
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@ -1173,6 +1173,9 @@ static void *arena_palloc(arena_t *arena, size_t alignment, size_t size,
size_t alloc_size);
static bool arena_is_large(const void *ptr);
static size_t arena_salloc(const void *ptr);
static void
arena_dalloc_bin_run(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
arena_bin_t *bin);
#ifdef JEMALLOC_STATS
static void arena_stats_print(arena_t *arena, bool bins, bool large);
#endif
@ -2263,8 +2266,7 @@ rb_wrap(static JEMALLOC_ATTR(unused), arena_avail_tree_, arena_avail_tree_t,
arena_chunk_map_t, link, arena_avail_comp)
static inline void
arena_run_rc_incr(arena_run_t *run, arena_bin_t *bin, const void *ptr,
unsigned regind)
arena_run_rc_incr(arena_run_t *run, arena_bin_t *bin, const void *ptr)
{
arena_chunk_t *chunk;
arena_t *arena;
@ -2292,8 +2294,7 @@ arena_run_rc_incr(arena_run_t *run, arena_bin_t *bin, const void *ptr,
}
static inline void
arena_run_rc_decr(arena_run_t *run, arena_bin_t *bin, const void *ptr,
unsigned regind)
arena_run_rc_decr(arena_run_t *run, arena_bin_t *bin, const void *ptr)
{
arena_chunk_t *chunk;
arena_t *arena;
@ -2392,7 +2393,7 @@ arena_run_reg_alloc(arena_run_t *run, arena_bin_t *bin)
mask ^= (1U << bit);
run->regs_mask[i] = mask;
arena_run_rc_incr(run, bin, ret, regind);
arena_run_rc_incr(run, bin, ret);
return (ret);
}
@ -2418,7 +2419,7 @@ arena_run_reg_alloc(arena_run_t *run, arena_bin_t *bin)
*/
run->regs_minelm = i; /* Low payoff: + (mask == 0); */
arena_run_rc_incr(run, bin, ret, regind);
arena_run_rc_incr(run, bin, ret);
return (ret);
}
@ -2494,7 +2495,7 @@ arena_run_reg_dalloc(arena_run_t *run, arena_bin_t *bin, void *ptr, size_t size)
assert((run->regs_mask[elm] & (1U << bit)) == 0);
run->regs_mask[elm] |= (1U << bit);
arena_run_rc_decr(run, bin, ptr, regind);
arena_run_rc_decr(run, bin, ptr);
}
static void
@ -2776,19 +2777,19 @@ arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
size_t i;
for (i = 0; i < run_pages; i++) {
if ((chunk->map[run_ind + i].bits & CHUNK_MAP_DIRTY)
== 0) {
/*
* When (dirty == true), *all* pages within the run
* need to have their dirty bits set, because only
* small runs can create a mixture of clean/dirty
* pages, but such runs are passed to this function
* with (dirty == false).
*/
assert((chunk->map[run_ind + i].bits & CHUNK_MAP_DIRTY)
== 0);
chunk->ndirty++;
arena->ndirty++;
}
chunk->map[run_ind + i].bits = CHUNK_MAP_DIRTY;
}
if (chunk->dirtied == false) {
arena_chunk_tree_dirty_insert(&arena->chunks_dirty,
chunk);
chunk->dirtied = true;
}
} else {
size_t i;
@ -2860,11 +2861,19 @@ arena_run_dalloc(arena_t *arena, arena_run_t *run, bool dirty)
CHUNK_MAP_ALLOCATED)) == arena_maxclass)
arena_chunk_dealloc(arena, chunk);
if (dirty) {
if (chunk->dirtied == false) {
arena_chunk_tree_dirty_insert(&arena->chunks_dirty,
chunk);
chunk->dirtied = true;
}
/* Enforce opt_lg_dirty_mult. */
if (opt_lg_dirty_mult >= 0 && (arena->nactive >> opt_lg_dirty_mult) <
arena->ndirty)
if (opt_lg_dirty_mult >= 0 && (arena->nactive >>
opt_lg_dirty_mult) < arena->ndirty)
arena_purge(arena);
}
}
static void
arena_run_trim_head(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
@ -3014,6 +3023,7 @@ arena_bin_malloc_hard(arena_t *arena, arena_bin_t *bin)
* *) bin->run_size <= arena_maxclass
* *) bin->run_size <= RUN_MAX_SMALL
* *) run header overhead <= RUN_MAX_OVRHD (or header overhead relaxed).
* *) run header size < PAGE_SIZE
*
* bin->nregs, bin->regs_mask_nelms, and bin->reg0_offset are
* also calculated here, since these settings are all interdependent.
@ -3075,7 +3085,9 @@ arena_bin_run_size_calc(arena_bin_t *bin, size_t min_run_size)
(try_mask_nelms - 1)) > try_reg0_offset);
} while (try_run_size <= arena_maxclass && try_run_size <= RUN_MAX_SMALL
&& RUN_MAX_OVRHD * (bin->reg_size << 3) > RUN_MAX_OVRHD_RELAX
&& (try_reg0_offset << RUN_BFP) > RUN_MAX_OVRHD * try_run_size);
&& (try_reg0_offset << RUN_BFP) > RUN_MAX_OVRHD * try_run_size
&& (sizeof(arena_run_t) + (sizeof(unsigned) * (try_mask_nelms - 1)))
< PAGE_SIZE);
assert(sizeof(arena_run_t) + (sizeof(unsigned) * (good_mask_nelms - 1))
<= good_reg0_offset);
@ -3710,30 +3722,9 @@ arena_dalloc_bin(arena_t *arena, arena_chunk_t *chunk, void *ptr,
arena_run_reg_dalloc(run, bin, ptr, size);
run->nfree++;
if (run->nfree == bin->nregs) {
/* Deallocate run. */
if (run == bin->runcur)
bin->runcur = NULL;
else if (bin->nregs != 1) {
size_t run_pageind = (((uintptr_t)run -
(uintptr_t)chunk)) >> PAGE_SHIFT;
arena_chunk_map_t *run_mapelm =
&chunk->map[run_pageind];
/*
* This block's conditional is necessary because if the
* run only contains one region, then it never gets
* inserted into the non-full runs tree.
*/
arena_run_tree_remove(&bin->runs, run_mapelm);
}
#ifdef JEMALLOC_DEBUG
run->magic = 0;
#endif
arena_run_dalloc(arena, run, true);
#ifdef JEMALLOC_STATS
bin->stats.curruns--;
#endif
} else if (run->nfree == 1 && run != bin->runcur) {
if (run->nfree == bin->nregs)
arena_dalloc_bin_run(arena, chunk, run, bin);
else if (run->nfree == 1 && run != bin->runcur) {
/*
* Make sure that bin->runcur always refers to the lowest
* non-full run, if one exists.
@ -3779,6 +3770,57 @@ arena_dalloc_bin(arena_t *arena, arena_chunk_t *chunk, void *ptr,
#endif
}
static void
arena_dalloc_bin_run(arena_t *arena, arena_chunk_t *chunk, arena_run_t *run,
arena_bin_t *bin)
{
size_t run_ind;
/* Deallocate run. */
if (run == bin->runcur)
bin->runcur = NULL;
else if (bin->nregs != 1) {
size_t run_pageind = (((uintptr_t)run -
(uintptr_t)chunk)) >> PAGE_SHIFT;
arena_chunk_map_t *run_mapelm =
&chunk->map[run_pageind];
/*
* This block's conditional is necessary because if the
* run only contains one region, then it never gets
* inserted into the non-full runs tree.
*/
arena_run_tree_remove(&bin->runs, run_mapelm);
}
/*
* Mark the first page as dirty. The dirty bit for every other page in
* the run is already properly set, which means we can call
* arena_run_dalloc(..., false), thus potentially avoiding the needless
* creation of many dirty pages.
*/
run_ind = (size_t)(((uintptr_t)run - (uintptr_t)chunk) >> PAGE_SHIFT);
assert((chunk->map[run_ind].bits & CHUNK_MAP_DIRTY) == 0);
chunk->map[run_ind].bits |= CHUNK_MAP_DIRTY;
chunk->ndirty++;
arena->ndirty++;
#ifdef JEMALLOC_DEBUG
run->magic = 0;
#endif
arena_run_dalloc(arena, run, false);
#ifdef JEMALLOC_STATS
bin->stats.curruns--;
#endif
if (chunk->dirtied == false) {
arena_chunk_tree_dirty_insert(&arena->chunks_dirty, chunk);
chunk->dirtied = true;
}
/* Enforce opt_lg_dirty_mult. */
if (opt_lg_dirty_mult >= 0 && (arena->nactive >> opt_lg_dirty_mult) <
arena->ndirty)
arena_purge(arena);
}
#ifdef JEMALLOC_STATS
static void
arena_stats_print(arena_t *arena, bool bins, bool large)