From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760954Ab3LIIJP (ORCPT ); Mon, 9 Dec 2013 03:09:15 -0500 Received: from relay.parallels.com ([195.214.232.42]:35901 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755758Ab3LIIGL (ORCPT ); Mon, 9 Dec 2013 03:06:11 -0500 From: Vladimir Davydov To: , , , CC: , , , , , , , Glauber Costa , Mel Gorman , Rik van Riel Subject: [PATCH v13 13/16] vmscan: take at least one pass with shrinkers Date: Mon, 9 Dec 2013 12:05:54 +0400 Message-ID: <5287164773f8aade33ce17f3c91546c6e1afaf85.1386571280.git.vdavydov@parallels.com> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.30.16.96] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Glauber Costa In very low free kernel memory situations, it may be the case that we have less objects to free than our initial batch size. If this is the case, it is better to shrink those, and open space for the new workload then to keep them and fail the new allocations. In particular, we are concerned with the direct reclaim case for memcg. Although this same technique can be applied to other situations just as well, we will start conservative and apply it for that case, which is the one that matters the most. Signed-off-by: Glauber Costa Signed-off-by: Vladimir Davydov Cc: Dave Chinner Cc: Johannes Weiner Cc: Michal Hocko Cc: Andrew Morton Cc: Mel Gorman Cc: Rik van Riel --- mm/vmscan.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 1997813..b2a5be9 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -281,17 +281,22 @@ shrink_slab_node(struct shrink_control *shrinkctl, struct shrinker *shrinker, nr_pages_scanned, lru_pages, max_pass, delta, total_scan); - while (total_scan >= batch_size) { + while (total_scan > 0) { unsigned long ret; + unsigned long nr_to_scan = min(batch_size, total_scan); - shrinkctl->nr_to_scan = batch_size; + if (!shrinkctl->target_mem_cgroup && + total_scan < batch_size) + break; + + shrinkctl->nr_to_scan = nr_to_scan; ret = shrinker->scan_objects(shrinker, shrinkctl); if (ret == SHRINK_STOP) break; freed += ret; - count_vm_events(SLABS_SCANNED, batch_size); - total_scan -= batch_size; + count_vm_events(SLABS_SCANNED, nr_to_scan); + total_scan -= nr_to_scan; cond_resched(); } -- 1.7.10.4