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=-3.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,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 8B488ECDE46 for ; Thu, 25 Oct 2018 21:44:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48B142083E for ; Thu, 25 Oct 2018 21:44:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="lOxZz8N7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 48B142083E 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 S1727530AbeJZGTP (ORCPT ); Fri, 26 Oct 2018 02:19:15 -0400 Received: from mail.kernel.org ([198.145.29.99]:52626 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726195AbeJZGTP (ORCPT ); Fri, 26 Oct 2018 02:19:15 -0400 Received: from localhost (unknown [167.98.65.38]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D742F2075D; Thu, 25 Oct 2018 21:44:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1540503892; bh=rRvv4UOXbX/8dKHiRNw4hn94FGXXeSI5iKjeuDLRB2E=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lOxZz8N7IVtEQKymzQfPgm3JjbzOYZMxT7+bGl9iXG0pdBRJ7RqLnaX4n+5C8QYW5 C7e/vUy5PK9oONXFBnhvuzprwVtJwt33L7WQktHB0l1Tr+97/PH89yesh5/EmfBuzF BUMGOcZJHfZpt2V+pDQ4Q2KktEY9xMkKMF9/oiCk= Date: Thu, 25 Oct 2018 17:44:49 -0400 From: Sasha Levin To: Matthew Wilcox Cc: Andrew Morton , Michal Hocko , Roman Gushchin , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Kernel Team , Rik van Riel , Randy Dunlap , Sasha Levin Subject: Re: [RFC PATCH] mm: don't reclaim inodes with many attached pages Message-ID: <20181025214449.GA2015@sasha-vm> References: <20181023164302.20436-1-guro@fb.com> <20181024151950.36fe2c41957d807756f587ca@linux-foundation.org> <20181025092352.GP18839@dhcp22.suse.cz> <20181025124442.5513d282273786369bbb7460@linux-foundation.org> <20181025202014.GA216405@sasha-vm> <20181025202707.GL25444@bombadil.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20181025202707.GL25444@bombadil.infradead.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 25, 2018 at 01:27:07PM -0700, Matthew Wilcox wrote: >On Thu, Oct 25, 2018 at 04:20:14PM -0400, Sasha Levin wrote: >> On Thu, Oct 25, 2018 at 12:44:42PM -0700, Andrew Morton wrote: >> > Yup. Sasha, can you please take care of this? >> >> Sure, I'll revert it from current stable trees. >> >> Should 172b06c32b94 and this commit be backported once Roman confirms >> the issue is fixed? As far as I understand 172b06c32b94 addressed an >> issue FB were seeing in their fleet and needed to be fixed. > >I'm not sure I see "FB sees an issue in their fleet" and "needs to be >fixed in stable kernels" as related. FB's workload is different from >most people's workloads and FB has a large and highly-skilled team of >kernel engineers. Obviously I want this problem fixed in mainline, >but I don't know that most people benefit from having it fixed in stable. I don't want to make backporting decisions based on how big a certain company's kernel team is. I only mentioned FB explicitly to suggest that this issue is seen on real-life scenarios rather than on synthetic tests or code review. So yes, let's not run to fix it just because it's FB but also let's not ignore it because FB has a world-class kernel team. This should be done purely based on how likely this patch will regress stable kernels vs the severity of the bug it fixes. -- Thanks, Sasha