[Tarantool-patches] [PATCH] do not keep a slab in cache if new allocation does not fit
Georgy Kirichenko
georgy at tarantool.org
Mon Jan 27 22:39:07 MSK 2020
Do not allocate a new slab if there is a free slab in a region cache.
If a cached slab is not big enough then free it.
Follow up 67d7ab44ab09df3356929e3692a03321b31f3ebb
Fixes #12
Issue: https://github.com/tarantool/small/issues/12
Branch: https://github.com/tarantool/small/tree/g.kirichenko/gh-12-region-cache
diff --git a/small/region.h b/small/region.h
index d9be176..58481b0 100644
--- a/small/region.h
+++ b/small/region.h
@@ -157,14 +157,20 @@ region_reserve(struct region *region, size_t size)
if (size <= rslab_unused(slab))
return (char *) rslab_data(slab) + slab->used;
/* Try to get a slab from the region cache. */
- slab = rlist_last_entry(®ion->slabs.slabs,
- struct rslab,
- slab.next_in_list);
- if (slab->used == 0 && size <= rslab_unused(slab)) {
- /* Move this slab to the head. */
+ while ((slab = rlist_last_entry(®ion->slabs.slabs,
+ struct rslab,
+ slab.next_in_list))->used == 0) {
slab_list_del(®ion->slabs, &slab->slab, next_in_list);
- slab_list_add(®ion->slabs, &slab->slab, next_in_list);
- return (char *) rslab_data(slab);
+ if (size <= rslab_unused(slab)) {
+ /* Move this slab to the head. */
+ slab_list_add(®ion->slabs, &slab->slab, next_in_list);
+ return (char *) rslab_data(slab);
+ }
+ /*
+ * This cached slab could not be used so free it
+ * and try to use the next one.
+ */
+ slab_put(region->cache, (struct slab *)slab);
}
}
return region_reserve_slow(region, size);
--
2.25.0
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