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=-2.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 941A0C4360F for ; Mon, 18 Feb 2019 19:14:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 57FC521773 for ; Mon, 18 Feb 2019 19:14:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550517266; bh=7TrL3/Dx5Qd9idBQj7w4ezPkKcjRB5vD90M+9YssUZs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=vMfkwj5fnna7LxvzKBDcaTDiKxpbjvC6YyPSNksSDHJl9xp68rxysWVfm/OxvYB5G 0UecceSJThy7NOvr3bPkndY1EuWRi8eVxBqNlckOF4rfqehCkPjzu/B2kllCBCkXzT rrxlX4FIkGNh+h6zq9JL/gxVpsxHbSYM+8wgLAvQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729105AbfBRTOY (ORCPT ); Mon, 18 Feb 2019 14:14:24 -0500 Received: from mx2.suse.de ([195.135.220.15]:33320 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728501AbfBRTOY (ORCPT ); Mon, 18 Feb 2019 14:14:24 -0500 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 F384AABD5; Mon, 18 Feb 2019 19:14:22 +0000 (UTC) Date: Mon, 18 Feb 2019 20:14:21 +0100 From: Michal Hocko To: Roman Gushchin Cc: Greg Kroah-Hartman , Rik van Riel , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" , Dave Chinner , Wolfgang Walter , Spock , Andrew Morton , Linus Torvalds Subject: Re: [PATCH 4.20 71/92] Revert "mm: slowly shrink slabs with a relatively small number of objects" Message-ID: <20190218191421.GE4525@dhcp22.suse.cz> References: <20190218133454.668268457@linuxfoundation.org> <20190218133501.533140116@linuxfoundation.org> <20190218161634.GA30873@kroah.com> <20190218173825.GB4525@dhcp22.suse.cz> <20190218185738.GA3745@castle.DHCP.thefacebook.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190218185738.GA3745@castle.DHCP.thefacebook.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 On Mon 18-02-19 18:57:45, Roman Gushchin wrote: > On Mon, Feb 18, 2019 at 06:38:25PM +0100, Michal Hocko wrote: > > On Mon 18-02-19 17:16:34, Greg KH wrote: > > > On Mon, Feb 18, 2019 at 10:30:44AM -0500, Rik van Riel wrote: > > > > On Mon, 2019-02-18 at 14:43 +0100, Greg Kroah-Hartman wrote: > > > > > 4.20-stable review patch. If anyone has any objections, please let > > > > > me know. > > > > > > > > > > ------------------ > > > > > > > > > > From: Dave Chinner > > > > > > > > > > commit a9a238e83fbb0df31c3b9b67003f8f9d1d1b6c96 upstream. > > > > > > > > > > This reverts commit 172b06c32b9497 ("mm: slowly shrink slabs with a > > > > > relatively small number of objects"). > > > > > > > > This revert will result in the slab caches of dead > > > > cgroups with a small number of remaining objects never > > > > getting reclaimed, which can be a memory leak in some > > > > configurations. > > > > > > > > But hey, that's your tradeoff to make. > > > > > > That's what is in Linus's tree. Should we somehow diverge from that? > > > > I believe we should start working on a memcg specific solution to > > minimize regressions for others and start a more complex solution from > > there. > > > > Can we special case dead memcgs in the slab reclaim and reclaim more > > aggressively? > > It's probably better to start a new thread to discuss this issue agreed > (btw, doesn't LSF/MM looks like the best place to do it? I can send a proposal). I was about to do that if nobody else did. dropped the rest of the email because this really deserves a new discussion. -- Michal Hocko SUSE Labs