From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:54254 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725819AbeKQJ5V (ORCPT ); Sat, 17 Nov 2018 04:57:21 -0500 Date: Fri, 16 Nov 2018 18:42:54 -0500 From: Sasha Levin To: akpm@linux-foundation.org Cc: dairinin@gmail.com, guro@fb.com, mhocko@kernel.org, mm-commits@vger.kernel.org, rdunlap@infradead.org, riel@surriel.com, stable@vger.kernel.org, torvalds@linux-foundation.org Subject: Re: [patch 07/18] mm: don't reclaim inodes with many attached pages Message-ID: <20181116234254.GK1706@sasha-vm> References: <20181116230818.7gDYc8ifK%akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20181116230818.7gDYc8ifK%akpm@linux-foundation.org> Sender: stable-owner@vger.kernel.org List-ID: On Fri, Nov 16, 2018 at 03:08:18PM -0800, akpm@linux-foundation.org wrote: >From: Roman Gushchin >Subject: mm: don't reclaim inodes with many attached pages > >Spock reported that the commit 172b06c32b94 ("mm: slowly shrink slabs with >a relatively small number of objects") leads to a regression on his setup: >periodically the majority of the pagecache is evicted without an obvious >reason, while before the change the amount of free memory was balancing >around the watermark. > >The reason behind is that the mentioned above change created some minimal >background pressure on the inode cache. The problem is that if an inode >is considered to be reclaimed, all belonging pagecache page are stripped, >no matter how many of them are there. So, if a huge multi-gigabyte file >is cached in the memory, and the goal is to reclaim only few slab objects >(unused inodes), we still can eventually evict all gigabytes of the >pagecache at once. > >The workload described by Spock has few large non-mapped files in the >pagecache, so it's especially noticeable. > >To solve the problem let's postpone the reclaim of inodes, which have more >than 1 attached page. Let's wait until the pagecache pages will be >evicted naturally by scanning the corresponding LRU lists, and only then >reclaim the inode structure. > >Link: http://lkml.kernel.org/r/20181023164302.20436-1-guro@fb.com >Signed-off-by: Roman Gushchin >Reported-by: Spock >Tested-by: Spock >Reviewed-by: Andrew Morton >Cc: Michal Hocko >Cc: Rik van Riel >Cc: Randy Dunlap >Cc: [4.19.x] >Signed-off-by: Andrew Morton Should I grab the other 6 patches in this "series"? (see Roman's comments here: https://www.spinics.net/lists/stable/msg265152.html). None of those is tagged for stable. -- Thanks, Sasha