MEDIUM: pools: start to batch eviction from local caches
Since previous patch we can forcefully evict multiple objects from the
local cache, even when evicting basd on the LRU entries. Let's define
a compile-time configurable setting to batch releasing of objects. For
now we set this value to 8 items per round.
This is marked medium because eviction from the LRU will slightly change
in order to group the last items that are freed within a single cache
instead of accurately scanning only the oldest ones exactly in their
order of appearance. But this is required in order to evolve towards
batched removals.
diff --git a/include/haproxy/defaults.h b/include/haproxy/defaults.h
index 35ad50d..baa9aff 100644
--- a/include/haproxy/defaults.h
+++ b/include/haproxy/defaults.h
@@ -407,6 +407,10 @@
#define CONFIG_HAP_POOL_CACHE_SIZE 1048576
#endif
+#ifndef CONFIG_HAP_POOL_CLUSTER_SIZE
+#define CONFIG_HAP_POOL_CLUSTER_SIZE 8
+#endif
+
/* Number of samples used to compute the times reported in stats. A power of
* two is highly recommended, and this value multiplied by the largest response
* time must not overflow and unsigned int. See freq_ctr.h for more information.
diff --git a/src/pool.c b/src/pool.c
index 2a56cd4..13ecc5f 100644
--- a/src/pool.c
+++ b/src/pool.c
@@ -346,9 +346,10 @@
{
struct pool_cache_head *ph = &pool->cache[tid];
- while (ph->count >= 16 + pool_cache_count / 8 &&
+ while (ph->count >= CONFIG_HAP_POOL_CLUSTER_SIZE &&
+ ph->count >= 16 + pool_cache_count / 8 &&
pool_cache_bytes > CONFIG_HAP_POOL_CACHE_SIZE * 3 / 4) {
- pool_evict_last_items(pool, ph, 1);
+ pool_evict_last_items(pool, ph, CONFIG_HAP_POOL_CLUSTER_SIZE);
}
}
@@ -368,7 +369,7 @@
*/
ph = LIST_NEXT(&item->by_pool, struct pool_cache_head *, list);
pool = container_of(ph - tid, struct pool_head, cache);
- pool_evict_last_items(pool, ph, 1);
+ pool_evict_last_items(pool, ph, CONFIG_HAP_POOL_CLUSTER_SIZE);
} while (pool_cache_bytes > CONFIG_HAP_POOL_CACHE_SIZE * 7 / 8);
}
@@ -389,7 +390,7 @@
pool_cache_bytes += pool->size;
if (unlikely(pool_cache_bytes > CONFIG_HAP_POOL_CACHE_SIZE * 3 / 4)) {
- if (ph->count >= 16 + pool_cache_count / 8)
+ if (ph->count >= 16 + pool_cache_count / 8 + CONFIG_HAP_POOL_CLUSTER_SIZE)
pool_evict_from_local_cache(pool);
if (pool_cache_bytes > CONFIG_HAP_POOL_CACHE_SIZE)
pool_evict_from_local_caches();