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Use trylock in tcache_bin_flush when possible.

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During tcache gc, use tcache_bin_try_flush_small / _large so that we can skip
items with their bins locked already.
This commit is contained in:
Qi Wang 2017-04-25 13:31:45 -07:00 committed by Qi Wang
parent e2aad5e810
commit 8584adc451
3 changed files with 142 additions and 63 deletions
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8
include/jemalloc/internal/tcache_externs.h
View File

@ -33,8 +33,12 @@ void *tcache_alloc_small_hard(tsdn_t *tsdn, arena_t *arena, tcache_t *tcache,
tcache_bin_t *tbin, szind_t binind, bool *tcache_success);
void tcache_bin_flush_small(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
szind_t binind, unsigned rem);
void tcache_bin_flush_large(tsd_t *tsd, tcache_bin_t *tbin, szind_t binind,
unsigned rem, tcache_t *tcache);
unsigned tcache_bin_try_flush_small(tsd_t *tsd, tcache_t *tcache,
tcache_bin_t *tbin, szind_t binind, unsigned rem);
void tcache_bin_flush_large(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
szind_t binind, unsigned rem);
unsigned tcache_bin_try_flush_large(tsd_t *tsd, tcache_t *tcache,
tcache_bin_t *tbin, szind_t binind, unsigned rem);
void tcache_arena_reassociate(tsdn_t *tsdn, tcache_t *tcache,
arena_t *arena);
tcache_t *tcache_create_explicit(tsd_t *tsd);

4
include/jemalloc/internal/tcache_inlines.h
View File

@ -227,8 +227,8 @@ tcache_dalloc_large(tsd_t *tsd, tcache_t *tcache, void *ptr, szind_t binind,
tbin = tcache_large_bin_get(tcache, binind);
tbin_info = &tcache_bin_info[binind];
if (unlikely(tbin->ncached == tbin_info->ncached_max)) {
tcache_bin_flush_large(tsd, tbin, binind,
(tbin_info->ncached_max >> 1), tcache);
tcache_bin_flush_large(tsd, tcache, tbin, binind,
(tbin_info->ncached_max >> 1));
}
assert(tbin->ncached < tbin_info->ncached_max);
tbin->ncached++;

141
src/tcache.c
View File

@ -45,14 +45,16 @@ tcache_event_hard(tsd_t *tsd, tcache_t *tcache) {
} else {
tbin = tcache_large_bin_get(tcache, binind);
}
bool repeat_bin;
if (tbin->low_water > 0) {
/*
* Flush (ceiling) 3/4 of the objects below the low water mark.
*/
unsigned nflushed;
if (binind < NBINS) {
tcache_bin_flush_small(tsd, tcache, tbin, binind,
tbin->ncached - tbin->low_water + (tbin->low_water
>> 2));
nflushed = tcache_bin_try_flush_small(tsd, tcache, tbin,
binind, tbin->ncached - tbin->low_water +
(tbin->low_water >> 2));
/*
* Reduce fill count by 2X. Limit lg_fill_div such that
* the fill count is always at least 1.
@ -63,10 +65,13 @@ tcache_event_hard(tsd_t *tsd, tcache_t *tcache) {
tcache->lg_fill_div[binind]++;
}
} else {
tcache_bin_flush_large(tsd, tbin, binind, tbin->ncached
- tbin->low_water + (tbin->low_water >> 2), tcache);
nflushed = tcache_bin_try_flush_large(tsd, tcache, tbin,
binind, tbin->ncached - tbin->low_water +
(tbin->low_water >> 2));
}
} else if (tbin->low_water < 0) {
repeat_bin = (nflushed == 0);
} else {
if (tbin->low_water < 0) {
/*
* Increase fill count by 2X for small bins. Make sure
* lg_fill_div stays greater than 0.
@ -75,12 +80,15 @@ tcache_event_hard(tsd_t *tsd, tcache_t *tcache) {
tcache->lg_fill_div[binind]--;
}
}
tbin->low_water = tbin->ncached;
repeat_bin = false;
}
if (!repeat_bin) {
tcache->next_gc_bin++;
if (tcache->next_gc_bin == nhbins) {
tcache->next_gc_bin = 0;
}
tbin->low_water = tbin->ncached;
}
}
void *
@ -99,11 +107,9 @@ tcache_alloc_small_hard(tsdn_t *tsdn, arena_t *arena, tcache_t *tcache,
return ret;
}
void
tcache_bin_flush_small(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
szind_t binind, unsigned rem) {
bool merged_stats = false;
static unsigned
tcache_bin_flush_small_impl(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
szind_t binind, unsigned rem, bool must_flush) {
assert(binind < NBINS);
assert(rem <= tbin->ncached);
@ -116,9 +122,12 @@ tcache_bin_flush_small(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
item_extent[i] = iealloc(tsd_tsdn(tsd), *(tbin->avail - 1 - i));
}
bool merged_stats = false;
unsigned nflushed = 0;
unsigned nskipped = 0;
while (nflush > 0) {
/* Lock the arena bin associated with the first object. */
extent_t *extent = item_extent[0];
extent_t *extent = item_extent[nskipped];
arena_t *bin_arena = extent_arena_get(extent);
arena_bin_t *bin = &bin_arena->bins[binind];
@ -130,7 +139,16 @@ tcache_bin_flush_small(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
tcache->prof_accumbytes = 0;
}
if (must_flush) {
malloc_mutex_lock(tsd_tsdn(tsd), &bin->lock);
} else {
/* Make best effort to flush w/o blocking. */
if (malloc_mutex_trylock(tsd_tsdn(tsd), &bin->lock)) {
nskipped++;
nflush--;
continue;
}
}
if (config_stats && bin_arena == arena) {
assert(!merged_stats);
merged_stats = true;
@ -139,7 +157,7 @@ tcache_bin_flush_small(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
tbin->tstats.nrequests = 0;
}
unsigned ndeferred = 0;
for (unsigned i = 0; i < nflush; i++) {
for (unsigned i = nskipped; i < nflush; i++) {
void *ptr = *(tbin->avail - 1 - i);
extent = item_extent[i];
assert(ptr != NULL && extent != NULL);
@ -154,13 +172,14 @@ tcache_bin_flush_small(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
* locked. Stash the object, so that it can be
* handled in a future pass.
*/
*(tbin->avail - 1 - ndeferred) = ptr;
item_extent[ndeferred] = extent;
*(tbin->avail - 1 - ndeferred - nskipped) = ptr;
item_extent[ndeferred + nskipped] = extent;
ndeferred++;
}
}
malloc_mutex_unlock(tsd_tsdn(tsd), &bin->lock);
arena_decay_ticks(tsd_tsdn(tsd), bin_arena, nflush - ndeferred);
nflushed += nflush - ndeferred;
nflush = ndeferred;
}
if (config_stats && !merged_stats) {
@ -169,26 +188,49 @@ tcache_bin_flush_small(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
* arena, so the stats didn't get merged. Manually do so now.
*/
arena_bin_t *bin = &arena->bins[binind];
if (must_flush) {
malloc_mutex_lock(tsd_tsdn(tsd), &bin->lock);
}
if (must_flush ||
!malloc_mutex_trylock(tsd_tsdn(tsd), &bin->lock)) {
malloc_mutex_assert_owner(tsd_tsdn(tsd), &bin->lock);
bin->stats.nflushes++;
bin->stats.nrequests += tbin->tstats.nrequests;
tbin->tstats.nrequests = 0;
malloc_mutex_unlock(tsd_tsdn(tsd), &bin->lock);
}
}
assert(nflushed == tbin->ncached - rem - nskipped);
assert(nskipped == 0 || !must_flush);
memmove(tbin->avail - rem, tbin->avail - tbin->ncached, rem *
sizeof(void *));
tbin->ncached = rem;
if (nflushed > 0) {
memmove(tbin->avail - (rem + nskipped), tbin->avail -
tbin->ncached, rem * sizeof(void *));
}
tbin->ncached = rem + nskipped;
if ((low_water_t)tbin->ncached < tbin->low_water) {
tbin->low_water = tbin->ncached;
}
return nflushed;
}
void
tcache_bin_flush_large(tsd_t *tsd, tcache_bin_t *tbin, szind_t binind,
unsigned rem, tcache_t *tcache) {
bool merged_stats = false;
tcache_bin_flush_small(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
szind_t binind, unsigned rem) {
tcache_bin_flush_small_impl(tsd, tcache, tbin, binind, rem, true);
}
unsigned
tcache_bin_try_flush_small(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
szind_t binind, unsigned rem) {
return tcache_bin_flush_small_impl(tsd, tcache, tbin, binind, rem,
false);
}
static unsigned
tcache_bin_flush_large_impl(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
szind_t binind, unsigned rem, bool must_flush) {
assert(binind < nhbins);
assert(rem <= tbin->ncached);
@ -201,18 +243,31 @@ tcache_bin_flush_large(tsd_t *tsd, tcache_bin_t *tbin, szind_t binind,
item_extent[i] = iealloc(tsd_tsdn(tsd), *(tbin->avail - 1 - i));
}
bool merged_stats = false;
unsigned nflushed = 0;
unsigned nskipped = 0;
while (nflush > 0) {
/* Lock the arena associated with the first object. */
extent_t *extent = item_extent[0];
extent_t *extent = item_extent[nskipped];
arena_t *locked_arena = extent_arena_get(extent);
UNUSED bool idump;
if (config_prof) {
idump = false;
}
if (must_flush) {
malloc_mutex_lock(tsd_tsdn(tsd), &locked_arena->large_mtx);
for (unsigned i = 0; i < nflush; i++) {
} else {
/* Make best effort to flush w/o blocking. */
if (malloc_mutex_trylock(tsd_tsdn(tsd),
&locked_arena->large_mtx)) {
nskipped++;
nflush--;
continue;
}
}
for (unsigned i = nskipped; i < nflush; i++) {
void *ptr = *(tbin->avail - 1 - i);
assert(ptr != NULL);
extent = item_extent[i];
@ -238,7 +293,7 @@ tcache_bin_flush_large(tsd_t *tsd, tcache_bin_t *tbin, szind_t binind,
malloc_mutex_unlock(tsd_tsdn(tsd), &locked_arena->large_mtx);
unsigned ndeferred = 0;
for (unsigned i = 0; i < nflush; i++) {
for (unsigned i = nskipped; i < nflush; i++) {
void *ptr = *(tbin->avail - 1 - i);
extent = item_extent[i];
assert(ptr != NULL && extent != NULL);
@ -252,8 +307,8 @@ tcache_bin_flush_large(tsd_t *tsd, tcache_bin_t *tbin, szind_t binind,
* Stash the object, so that it can be handled
* in a future pass.
*/
*(tbin->avail - 1 - ndeferred) = ptr;
item_extent[ndeferred] = extent;
*(tbin->avail - 1 - ndeferred - nskipped) = ptr;
item_extent[ndeferred + nskipped] = extent;
ndeferred++;
}
}
@ -262,6 +317,7 @@ tcache_bin_flush_large(tsd_t *tsd, tcache_bin_t *tbin, szind_t binind,
}
arena_decay_ticks(tsd_tsdn(tsd), locked_arena, nflush -
ndeferred);
nflushed += nflush - ndeferred;
nflush = ndeferred;
}
if (config_stats && !merged_stats) {
@ -274,12 +330,31 @@ tcache_bin_flush_large(tsd_t *tsd, tcache_bin_t *tbin, szind_t binind,
tbin->tstats.nrequests = 0;
}
memmove(tbin->avail - rem, tbin->avail - tbin->ncached, rem *
sizeof(void *));
tbin->ncached = rem;
assert(nflushed == tbin->ncached - rem - nskipped);
assert(nskipped == 0 || !must_flush);
if (nflushed > 0) {
memmove(tbin->avail - (rem + nskipped), tbin->avail -
tbin->ncached, rem * sizeof(void *));
}
tbin->ncached = rem + nskipped;
if ((low_water_t)tbin->ncached < tbin->low_water) {
tbin->low_water = tbin->ncached;
}
return nflushed;
}
void
tcache_bin_flush_large(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
szind_t binind, unsigned rem) {
tcache_bin_flush_large_impl(tsd, tcache, tbin, binind, rem, true);
}
unsigned
tcache_bin_try_flush_large(tsd_t *tsd, tcache_t *tcache, tcache_bin_t *tbin,
szind_t binind, unsigned rem) {
return tcache_bin_flush_large_impl(tsd, tcache, tbin, binind, rem,
false);
}
void
@ -461,7 +536,7 @@ tcache_flush_cache(tsd_t *tsd, tcache_t *tcache) {
}
for (unsigned i = NBINS; i < nhbins; i++) {
tcache_bin_t *tbin = tcache_large_bin_get(tcache, i);
tcache_bin_flush_large(tsd, tbin, i, 0, tcache);
tcache_bin_flush_large(tsd, tcache, tbin, i, 0);
if (config_stats) {
assert(tbin->tstats.nrequests == 0);