From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 82434C6786E for ; Fri, 26 Oct 2018 08:57:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3C23420834 for ; Fri, 26 Oct 2018 08:57:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3C23420834 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726531AbeJZReD (ORCPT ); Fri, 26 Oct 2018 13:34:03 -0400 Received: from mx2.suse.de ([195.135.220.15]:54312 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726078AbeJZReD (ORCPT ); Fri, 26 Oct 2018 13:34:03 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id A5201AD1D; Fri, 26 Oct 2018 08:57:49 +0000 (UTC) Date: Fri, 26 Oct 2018 10:57:35 +0200 From: Michal Hocko To: Roman Gushchin Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Kernel Team , Rik van Riel , Randy Dunlap , Andrew Morton , dairinin@gmail.com Subject: Re: [RFC PATCH] mm: don't reclaim inodes with many attached pages Message-ID: <20181026085735.GZ18839@dhcp22.suse.cz> References: <20181023164302.20436-1-guro@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181023164302.20436-1-guro@fb.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Spock doesn't seem to be cced here - fixed now On Tue 23-10-18 16:43:29, Roman Gushchin wrote: > 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. Has this actually fixed/worked around the issue? > Reported-by: Spock > Signed-off-by: Roman Gushchin > Cc: Michal Hocko > Cc: Rik van Riel > Cc: Randy Dunlap > Cc: Andrew Morton > --- > fs/inode.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/fs/inode.c b/fs/inode.c > index 73432e64f874..0cd47fe0dbe5 100644 > --- a/fs/inode.c > +++ b/fs/inode.c > @@ -730,8 +730,11 @@ static enum lru_status inode_lru_isolate(struct list_head *item, > return LRU_REMOVED; > } > > - /* recently referenced inodes get one more pass */ > - if (inode->i_state & I_REFERENCED) { > + /* > + * Recently referenced inodes and inodes with many attached pages > + * get one more pass. > + */ > + if (inode->i_state & I_REFERENCED || inode->i_data.nrpages > 1) { The comment is just confusing. Did you mean to say s@many@any@ ? > inode->i_state &= ~I_REFERENCED; > spin_unlock(&inode->i_lock); > return LRU_ROTATE; > -- > 2.17.2 -- Michal Hocko SUSE Labs