Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754768AbbKWQaT (ORCPT ); Mon, 23 Nov 2015 11:30:19 -0500 Received: from gum.cmpxchg.org ([85.214.110.215]:45388 "EHLO gum.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751057AbbKWQaP (ORCPT ); Mon, 23 Nov 2015 11:30:15 -0500 Date: Mon, 23 Nov 2015 11:30:03 -0500 From: Johannes Weiner To: Vladimir Davydov Cc: Andrew Morton , Michal Hocko , Vlastimil Babka , Mel Gorman , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] vmscan: do not force-scan file lru if its absolute size is small Message-ID: <20151123163003.GC13000@cmpxchg.org> References: <20151120134311.8ff0947215fc522f72f791fe@linux-foundation.org> <1448275173-10538-1-git-send-email-vdavydov@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1448275173-10538-1-git-send-email-vdavydov@virtuozzo.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1482 Lines: 27 On Mon, Nov 23, 2015 at 01:39:33PM +0300, Vladimir Davydov wrote: > We assume there is enough inactive page cache if the size of inactive > file lru is greater than the size of active file lru, in which case we > force-scan file lru ignoring anonymous pages. While this logic works > fine when there are plenty of page cache pages, it fails if the size of > file lru is small (several MB): in this case (lru_size >> prio) will be > 0 for normal scan priorities, as a result, if inactive file lru happens > to be larger than active file lru, anonymous pages of a cgroup will > never get evicted unless the system experiences severe memory pressure, > even if there are gigabytes of unused anonymous memory there, which is > unfair in respect to other cgroups, whose workloads might be page cache > oriented. > > This patch attempts to fix this by elaborating the "enough inactive page > cache" check: it makes it not only check that inactive lru size > active > lru size, but also that we will scan something from the cgroup at the > current scan priority. If these conditions do not hold, we proceed to > SCAN_FRACT as usual. > > Signed-off-by: Vladimir Davydov Acked-by: Johannes Weiner -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/