From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrey Ryabinin Subject: [PATCH v5 2/2] mm/memcontrol.c: Reduce reclaim retries in mem_cgroup_resize_limit() Date: Fri, 19 Jan 2018 16:25:44 +0300 Message-ID: <20180119132544.19569-2-aryabinin@virtuozzo.com> References: <20171220102429.31601-1-aryabinin@virtuozzo.com> <20180119132544.19569-1-aryabinin@virtuozzo.com> Mime-Version: 1.0 Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=virtuozzo.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version; bh=o4RMv/d7L1ZXPGLpDcLbc8Dnuyuug1U0NElJ29Otdr4=; b=VQzaCMZ7hekQjXipWVgrHFCR6fp0uyPeaExUzV0KuD1BeS/CkhFZB63JCqYiW86ymZQTBGZbXu0l/C5rSNOJ9eqofG+gahwYno6V5oOdqFbNn0HL3rnidqVYHEn9hvmBYcWIn8QFSDZ/SrI4bn6QRxSrxA/mWtyFhfDGWeaHMc8= In-Reply-To: <20180119132544.19569-1-aryabinin@virtuozzo.com> Sender: owner-linux-mm@kvack.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Andrew Morton Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrey Ryabinin , Shakeel Butt , Michal Hocko , Johannes Weiner , Vladimir Davydov Currently mem_cgroup_resize_limit() retries to set limit after reclaiming 32 pages. It makes more sense to reclaim needed amount of pages right away. This works noticeably faster, especially if 'usage - limit' big. E.g. bringing down limit from 4G to 50M: Before: # perf stat echo 50M > memory.limit_in_bytes Performance counter stats for 'echo 50M': 386.582382 task-clock (msec) # 0.835 CPUs utilized 2,502 context-switches # 0.006 M/sec 0.463244382 seconds time elapsed After: # perf stat echo 50M > memory.limit_in_bytes Performance counter stats for 'echo 50M': 169.403906 task-clock (msec) # 0.849 CPUs utilized 14 context-switches # 0.083 K/sec 0.199536900 seconds time elapsed Signed-off-by: Andrey Ryabinin Cc: Shakeel Butt Cc: Michal Hocko Cc: Johannes Weiner Cc: Vladimir Davydov --- mm/memcontrol.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 9d987f3e79dc..09bac2df2f12 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2448,6 +2448,7 @@ static DEFINE_MUTEX(memcg_limit_mutex); static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long limit, bool memsw) { + unsigned long nr_pages; bool enlarge = false; int ret; bool limits_invariant; @@ -2479,8 +2480,9 @@ static int mem_cgroup_resize_limit(struct mem_cgroup *memcg, if (!ret) break; - if (!try_to_free_mem_cgroup_pages(memcg, 1, - GFP_KERNEL, !memsw)) { + nr_pages = max_t(long, 1, page_counter_read(counter) - limit); + if (!try_to_free_mem_cgroup_pages(memcg, nr_pages, + GFP_KERNEL, !memsw)) { ret = -EBUSY; break; } -- 2.13.6 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org