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_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 D2FD6C4646D for ; Wed, 15 Aug 2018 09:30:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 73C15216E4 for ; Wed, 15 Aug 2018 09:30:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 73C15216E4 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 S1728981AbeHOMV6 (ORCPT ); Wed, 15 Aug 2018 08:21:58 -0400 Received: from mx2.suse.de ([195.135.220.15]:47394 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728583AbeHOMV6 (ORCPT ); Wed, 15 Aug 2018 08:21:58 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay1.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id DBEC7AD04; Wed, 15 Aug 2018 09:30:32 +0000 (UTC) Date: Wed, 15 Aug 2018 11:30:32 +0200 From: Michal Hocko To: Mike Rapoport Cc: linux-mm@kvack.org, Jonathan Corbet , Matthew Wilcox , Vlastimil Babka , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] docs/core-api: add memory allocation guide Message-ID: <20180815093032.GQ32645@dhcp22.suse.cz> References: <1534314887-9202-1-git-send-email-rppt@linux.vnet.ibm.com> <20180815063649.GB24091@rapoport-lnx> <20180815081539.GN32645@dhcp22.suse.cz> <20180815090428.GD24091@rapoport-lnx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180815090428.GD24091@rapoport-lnx> 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 Wed 15-08-18 12:04:29, Mike Rapoport wrote: [...] > How about: > > * If the allocation is performed from an atomic context, e.g interrupt > handler, use ``GFP_NOWARN``. This flag prevents direct reclaim and IO or > filesystem operations. Consequently, under memory pressure ``GFP_NOWARN`` > allocation is likely to fail. s@NOWARN@NOWAIT@ I guess. Looks good otherwise. I would even go and mention GFP_NOWARN once you brought it up. Allocations which have a reasonable fallback should be using NOWARN. > * If you think that accessing memory reserves is justified and the kernel > will be stressed unless allocation succeeds, you may use ``GFP_ATOMIC``. OK otherwise. -- Michal Hocko SUSE Labs