From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id E63D86B0038 for ; Thu, 29 Dec 2016 21:05:25 -0500 (EST) Received: by mail-pg0-f71.google.com with SMTP id u5so580616354pgi.7 for ; Thu, 29 Dec 2016 18:05:25 -0800 (PST) Received: from lgeamrelo13.lge.com (LGEAMRELO13.lge.com. [156.147.23.53]) by mx.google.com with ESMTP id h9si25327474pli.37.2016.12.29.18.05.24 for ; Thu, 29 Dec 2016 18:05:25 -0800 (PST) Date: Fri, 30 Dec 2016 11:05:22 +0900 From: Minchan Kim Subject: Re: [RFC PATCH] mm, memcg: fix (Re: OOM: Better, but still there on) Message-ID: <20161230020522.GC4184@bbox> References: <20161222214611.GA3015@boerne.fritz.box> <20161223105157.GB23109@dhcp22.suse.cz> <20161223121851.GA27413@ppc-nas.fritz.box> <20161223125728.GE23109@dhcp22.suse.cz> <20161223144738.GB23117@dhcp22.suse.cz> <20161223222559.GA5568@teela.multi.box> <20161226124839.GB20715@dhcp22.suse.cz> <20161227155532.GI1308@dhcp22.suse.cz> <20161229012026.GB15541@bbox> <20161229090432.GE29208@dhcp22.suse.cz> MIME-Version: 1.0 In-Reply-To: <20161229090432.GE29208@dhcp22.suse.cz> Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Nils Holland , Mel Gorman , Johannes Weiner , Vladimir Davydov , Tetsuo Handa , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Chris Mason , David Sterba , linux-btrfs@vger.kernel.org On Thu, Dec 29, 2016 at 10:04:32AM +0100, Michal Hocko wrote: > On Thu 29-12-16 10:20:26, Minchan Kim wrote: > > On Tue, Dec 27, 2016 at 04:55:33PM +0100, Michal Hocko wrote: > > > Hi, > > > could you try to run with the following patch on top of the previous > > > one? I do not think it will make a large change in your workload but > > > I think we need something like that so some testing under which is known > > > to make a high lowmem pressure would be really appreciated. If you have > > > more time to play with it then running with and without the patch with > > > mm_vmscan_direct_reclaim_{start,end} tracepoints enabled could tell us > > > whether it make any difference at all. > > > > > > I would also appreciate if Mel and Johannes had a look at it. I am not > > > yet sure whether we need the same thing for anon/file balancing in > > > get_scan_count. I suspect we need but need to think more about that. > > > > > > Thanks a lot again! > > > --- > > > From b51f50340fe9e40b68be198b012f8ab9869c1850 Mon Sep 17 00:00:00 2001 > > > From: Michal Hocko > > > Date: Tue, 27 Dec 2016 16:28:44 +0100 > > > Subject: [PATCH] mm, vmscan: consider eligible zones in get_scan_count > > > > > > get_scan_count considers the whole node LRU size when > > > - doing SCAN_FILE due to many page cache inactive pages > > > - calculating the number of pages to scan > > > > > > in both cases this might lead to unexpected behavior especially on 32b > > > systems where we can expect lowmem memory pressure very often. > > > > > > A large highmem zone can easily distort SCAN_FILE heuristic because > > > there might be only few file pages from the eligible zones on the node > > > lru and we would still enforce file lru scanning which can lead to > > > trashing while we could still scan anonymous pages. > > > > Nit: > > It doesn't make thrashing because isolate_lru_pages filter out them > > but I agree it makes pointless CPU burning to find eligible pages. > > This is not about isolate_lru_pages. The trashing could happen if we had > lowmem pagecache user which would constantly reclaim recently faulted > in pages while there is anonymous memory in the lowmem which could be > reclaimed instead. > > [...] > > > /* > > > + * Return the number of pages on the given lru which are eligibne for the > > eligible > > fixed > > > > + * given zone_idx > > > + */ > > > +static unsigned long lruvec_lru_size_zone_idx(struct lruvec *lruvec, > > > + enum lru_list lru, int zone_idx) > > > > Nit: > > > > Although there is a comment, function name is rather confusing when I compared > > it with lruvec_zone_lru_size. > > I am all for a better name. > > > lruvec_eligible_zones_lru_size is better? > > this would be too easy to confuse with lruvec_eligible_zone_lru_size. > What about lruvec_lru_size_eligible_zones? Don't mind. > > > Nit: > > > > With this patch, inactive_list_is_low can use lruvec_lru_size_zone_idx rather than > > own custom calculation to filter out non-eligible pages. > > Yes, that would be possible and I was considering that. But then I found > useful to see total and reduced numbers in the tracepoint > http://lkml.kernel.org/r/20161228153032.10821-8-mhocko@kernel.org > and didn't want to call lruvec_lru_size 2 times. But if you insist then > I can just do that. I don't mind either but I think we need to describe the reason if you want to go with your open-coded version. Otherwise, someone will try to fix it. -- 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