From: Willy Tarreau <w@1wt.eu>
Date: Sun, 2 Jan 2022 16:53:02 +0000 (+0100)
Subject: MEDIUM: pools: release cached objects in batches
X-Git-Tag: v2.6-dev1~191
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1513c5479;p=thirdparty%2Fhaproxy.git

MEDIUM: pools: release cached objects in batches

With this patch pool_evict_last_items builds clusters of up to
CONFIG_HAP_POOL_CLUSTER_SIZE entries so that accesses to the shared
pools are reduced by CONFIG_HAP_POOL_CLUSTER_SIZE and the inter-
thread contention is reduced by as much..
---

diff --git a/src/pool.c b/src/pool.c
index 13ecc5fb09..a3b14d2417 100644
--- a/src/pool.c
+++ b/src/pool.c
@@ -310,8 +310,9 @@ void pool_free_nocache(struct pool_head *pool, void *ptr)
 static void pool_evict_last_items(struct pool_head *pool, struct pool_cache_head *ph, uint count)
 {
 	struct pool_cache_item *item;
-	struct pool_item *pi;
+	struct pool_item *pi, *head = NULL;
 	uint released = 0;
+	uint cluster = 0;
 	uint to_free_max;
 
 	to_free_max = pool_releasable(pool);
@@ -320,17 +321,29 @@ static void pool_evict_last_items(struct pool_head *pool, struct pool_cache_head
 		item = LIST_PREV(&ph->list, typeof(item), by_pool);
 		LIST_DELETE(&item->by_pool);
 		LIST_DELETE(&item->by_lru);
-		released++;
 
-		if (to_free_max) {
+		if (to_free_max > released || cluster) {
 			pi = (struct pool_item *)item;
-			pi->down = NULL;
-			pool_put_to_shared_cache(pool, pi, 1);
-			to_free_max--;
+			pi->next = NULL;
+			pi->down = head;
+			head = pi;
+			cluster++;
+			if (cluster >= CONFIG_HAP_POOL_CLUSTER_SIZE) {
+				/* enough to make a cluster */
+				pool_put_to_shared_cache(pool, head, cluster);
+				cluster = 0;
+				head = NULL;
+			}
 		} else
 			pool_free_nocache(pool, item);
+
+		released++;
 	}
 
+	/* incomplete cluster left */
+	if (cluster)
+		pool_put_to_shared_cache(pool, head, cluster);
+
 	ph->count -= released;
 	pool_cache_count -= released;
 	pool_cache_bytes -= released * pool->size;