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=-2.5 required=3.0 tests=MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 A9FB1ECDE20 for ; Wed, 11 Sep 2019 12:00:08 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7748D2168B for ; Wed, 11 Sep 2019 12:00:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7748D2168B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E564D6B0005; Wed, 11 Sep 2019 08:00:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E06DA6B0006; Wed, 11 Sep 2019 08:00:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D1CCB6B0007; Wed, 11 Sep 2019 08:00:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0092.hostedemail.com [216.40.44.92]) by kanga.kvack.org (Postfix) with ESMTP id B14756B0005 for ; Wed, 11 Sep 2019 08:00:07 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with SMTP id EE8E6BEF6 for ; Wed, 11 Sep 2019 12:00:06 +0000 (UTC) X-FDA: 75922496412.05.hook96_1e0e8597b8d61 X-HE-Tag: hook96_1e0e8597b8d61 X-Filterd-Recvd-Size: 2841 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Wed, 11 Sep 2019 12:00:06 +0000 (UTC) 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 7A9D9B64B; Wed, 11 Sep 2019 12:00:04 +0000 (UTC) Date: Wed, 11 Sep 2019 14:00:02 +0200 From: Michal Hocko To: Shakeel Butt Cc: Andrew Morton , Johannes Weiner , Vladimir Davydov , LKML , Linux MM , Andrey Ryabinin , Thomas Lindroth , Tetsuo Handa Subject: Re: [PATCH] memcg, kmem: do not fail __GFP_NOFAIL charges Message-ID: <20190911120002.GQ4023@dhcp22.suse.cz> References: <31131c2d-a936-8bbf-e58d-a3baaa457340@gmail.com> <20190906125608.32129-1-mhocko@kernel.org> <20190909112245.GH27159@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190909112245.GH27159@dhcp22.suse.cz> User-Agent: Mutt/1.10.1 (2018-07-13) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon 09-09-19 13:22:45, Michal Hocko wrote: > On Fri 06-09-19 11:24:55, Shakeel Butt wrote: [...] > > I wonder what has changed since > > . > > I have completely forgot about that one. It seems that we have just > repeated the same discussion again. This time we have a poor user who > actually enabled the kmem limit. > > I guess there was no real objection to the change back then. The primary > discussion revolved around the fact that the accounting will stay broken > even when this particular part was fixed. Considering this leads to easy > to trigger crash (with the limit enabled) then I guess we should just > make it less broken and backport to stable trees and have a serious > discussion about discontinuing of the limit. Start by simply failing to > set any limit in the current upstream kernels. Any more concerns/objections to the patch? I can add a reference to your earlier post Shakeel if you want or to credit you the way you prefer. Also are there any objections to start deprecating process of kmem limit? I would see it in two stages - 1st warn in the kernel log pr_warn("kmem.limit_in_bytes is deprecated and will be removed. "Please report your usecase to linux-mm@kvack.org if you " "depend on this functionality." - 2nd fail any write to kmem.limit_in_bytes - 3rd remove the control file completely -- Michal Hocko SUSE Labs