Extract bin shard selection out of bin locking

3 files changed, 23 insertions, 22 deletions

diff --git a/include/jemalloc/internal/arena_externs.h b/include/jemalloc/internal/arena_externs.h
index 674c98f5..c600d10f 100644
--- a/include/jemalloc/internal/arena_externs.h
+++ b/include/jemalloc/internal/arena_externs.h
@@ -85,7 +85,7 @@ arena_t *arena_new(tsdn_t *tsdn, unsigned ind, extent_hooks_t *extent_hooks);
 bool arena_init_huge(void);
 bool arena_is_huge(unsigned arena_ind);
 arena_t *arena_choose_huge(tsd_t *tsd);
-bin_t *arena_bin_choose_lock(tsdn_t *tsdn, arena_t *arena, szind_t binind,
+bin_t *arena_bin_choose(tsdn_t *tsdn, arena_t *arena, szind_t binind,
     unsigned *binshard);
 void arena_boot(sc_data_t *sc_data);
 void arena_prefork0(tsdn_t *tsdn, arena_t *arena);
diff --git a/src/arena.c b/src/arena.c
index 46da3859..1df276b0 100644
--- a/src/arena.c
+++ b/src/arena.c
@@ -739,21 +739,20 @@ arena_bin_refill_slabcur_no_fresh_slab(tsdn_t *tsdn, arena_t *arena,
 	return (bin->slabcur == NULL);
 }
 
-/* Choose a bin shard and return the locked bin. */
 bin_t *
-arena_bin_choose_lock(tsdn_t *tsdn, arena_t *arena, szind_t binind,
-    unsigned *binshard) {
-	bin_t *bin;
+arena_bin_choose(tsdn_t *tsdn, arena_t *arena, szind_t binind,
+    unsigned *binshard_p) {
+	unsigned binshard;
 	if (tsdn_null(tsdn) || tsd_arena_get(tsdn_tsd(tsdn)) == NULL) {
-		*binshard = 0;
+		binshard = 0;
 	} else {
-		*binshard = tsd_binshardsp_get(tsdn_tsd(tsdn))->binshard[binind];
+		binshard = tsd_binshardsp_get(tsdn_tsd(tsdn))->binshard[binind];
 	}
-	assert(*binshard < bin_infos[binind].n_shards);
-	bin = &arena->bins[binind].bin_shards[*binshard];
-	malloc_mutex_lock(tsdn, &bin->lock);
-
-	return bin;
+	assert(binshard < bin_infos[binind].n_shards);
+	if (binshard_p != NULL) {
+		*binshard_p = binshard;
+	}
+	return &arena->bins[binind].bin_shards[binshard];
 }
 
 void
@@ -797,11 +796,12 @@ arena_cache_bin_fill_small(tsdn_t *tsdn, arena_t *arena,
 	edata_t *fresh_slab = NULL;
 	bool alloc_and_retry = false;
 	unsigned filled = 0;
-
-	bin_t *bin;
 	unsigned binshard;
+	bin_t *bin = arena_bin_choose(tsdn, arena, binind, &binshard);
+
 label_refill:
-	bin = arena_bin_choose_lock(tsdn, arena, binind, &binshard);
+	malloc_mutex_lock(tsdn, &bin->lock);
+
 	while (filled < nfill) {
 		/* Try batch-fill from slabcur first. */
 		edata_t *slabcur = bin->slabcur;
@@ -854,6 +854,7 @@ label_refill:
 		bin->stats.nfills++;
 		cache_bin->tstats.nrequests = 0;
 	}
+
 	malloc_mutex_unlock(tsdn, &bin->lock);
 
 	if (alloc_and_retry) {
@@ -906,8 +907,9 @@ arena_malloc_small(tsdn_t *tsdn, arena_t *arena, szind_t binind, bool zero) {
 	const bin_info_t *bin_info = &bin_infos[binind];
 	size_t usize = sz_index2size(binind);
 	unsigned binshard;
-	bin_t *bin = arena_bin_choose_lock(tsdn, arena, binind, &binshard);
+	bin_t *bin = arena_bin_choose(tsdn, arena, binind, &binshard);
 
+	malloc_mutex_lock(tsdn, &bin->lock);
 	edata_t *fresh_slab = NULL;
 	void *ret = arena_bin_malloc_no_fresh_slab(tsdn, arena, bin, binind);
 	if (ret == NULL) {
diff --git a/src/tcache.c b/src/tcache.c
index a33d9e24..b681ee10 100644
--- a/src/tcache.c
+++ b/src/tcache.c
@@ -454,9 +454,9 @@ tcache_bin_flush_impl(tsd_t *tsd, tcache_t *tcache, cache_bin_t *cache_bin,
 			 * thread's arena, so the stats didn't get merged.
 			 * Manually do so now.
 			 */
-			unsigned binshard;
-			bin_t *bin = arena_bin_choose_lock(tsdn, tcache_arena,
-			    binind, &binshard);
+			bin_t *bin = arena_bin_choose(tsdn, tcache_arena,
+			    binind, NULL);
+			malloc_mutex_lock(tsdn, &bin->lock);
 			bin->stats.nflushes++;
 			bin->stats.nrequests += cache_bin->tstats.nrequests;
 			cache_bin->tstats.nrequests = 0;
@@ -751,9 +751,8 @@ tcache_stats_merge(tsdn_t *tsdn, tcache_t *tcache, arena_t *arena) {
 	for (unsigned i = 0; i < nhbins; i++) {
 		cache_bin_t *cache_bin = &tcache->bins[i];
 		if (i < SC_NBINS) {
-			unsigned binshard;
-			bin_t *bin = arena_bin_choose_lock(tsdn, arena, i,
-			    &binshard);
+			bin_t *bin = arena_bin_choose(tsdn, arena, i, NULL);
+			malloc_mutex_lock(tsdn, &bin->lock);
 			bin->stats.nrequests += cache_bin->tstats.nrequests;
 			malloc_mutex_unlock(tsdn, &bin->lock);
 		} else {