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=-1.0 required=3.0 tests=MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by aws-us-west-2-korg-lkml-1.web.codeaurora.org (Postfix) with ESMTP id B9552C433EF for ; Wed, 13 Jun 2018 13:39:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6FE5A208B3 for ; Wed, 13 Jun 2018 13:39:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6FE5A208B3 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 S935547AbeFMNjS (ORCPT ); Wed, 13 Jun 2018 09:39:18 -0400 Received: from mx2.suse.de ([195.135.220.15]:46943 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934987AbeFMNjR (ORCPT ); Wed, 13 Jun 2018 09:39:17 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext-too.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 0AC38AE1B; Wed, 13 Jun 2018 13:39:16 +0000 (UTC) Date: Wed, 13 Jun 2018 15:39:13 +0200 From: Michal Hocko To: Christoph Hellwig Cc: Marek Szyprowski , Matthew Wilcox , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Andrew Morton , Michal Nazarewicz , Joonsoo Kim , Vlastimil Babka Subject: Re: [PATCH] mm: cma: honor __GFP_ZERO flag in cma_alloc() Message-ID: <20180613133913.GD20315@dhcp22.suse.cz> References: <20180613085851eucas1p20337d050face8ff8ea87674e16a9ccd2~3rI_9nj8b0455904559eucas1p2C@eucas1p2.samsung.com> <20180613122359.GA8695@bombadil.infradead.org> <20180613124001eucas1p2422f7916367ce19fecd40d6131990383~3uKFrT3ML1977219772eucas1p2G@eucas1p2.samsung.com> <20180613125546.GB32016@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180613125546.GB32016@infradead.org> User-Agent: Mutt/1.9.5 (2018-04-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 13-06-18 05:55:46, Christoph Hellwig wrote: > On Wed, Jun 13, 2018 at 02:40:00PM +0200, Marek Szyprowski wrote: > > It is not only the matter of the spinlocks. GFP_ATOMIC is not supported > > by the > > memory compaction code, which is used in alloc_contig_range(). Right, this > > should be also noted in the documentation. > > Documentation is good, asserts are better. The code should reject any > flag not explicitly supported, or even better have its own flags type > with the few actually supported flags. Agreed. Is the cma allocator used for anything other than GFP_KERNEL btw.? If not then, shouldn't we simply drop the gfp argument altogether rather than give users a false hope for differen gfp modes that are not really supported and grow broken code? -- Michal Hocko SUSE Labs