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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 432F6C433F5 for ; Fri, 25 Mar 2022 16:49:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 2C41F6B0071; Fri, 25 Mar 2022 12:49:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 24D286B0073; Fri, 25 Mar 2022 12:49:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0ECFE6B0074; Fri, 25 Mar 2022 12:49:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id F02786B0071 for ; Fri, 25 Mar 2022 12:49:00 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id BCCD6247E6 for ; Fri, 25 Mar 2022 16:49:00 +0000 (UTC) X-FDA: 79283493240.12.6757CD6 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf08.hostedemail.com (Postfix) with ESMTP id EC76E16002E for ; Fri, 25 Mar 2022 16:48:59 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 4AA1668B05; Fri, 25 Mar 2022 17:48:56 +0100 (CET) Date: Fri, 25 Mar 2022 17:48:56 +0100 From: Christoph Hellwig To: Michal Hocko Cc: Andrew Morton , Christoph Hellwig , Baoquan He , John Donnelly , David Hildenbrand , linux-mm@kvack.org, LKML Subject: Re: [PATCH] dma/pool: do not complain if DMA pool is not allocated Message-ID: <20220325164856.GA16800@lst.de> References: <20220325122559.14251-1-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-Stat-Signature: 3kno4b6qqrsu46dgqtgymzc7fjf9q1mf X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: EC76E16002E Authentication-Results: imf08.hostedemail.com; dkim=none; spf=none (imf08.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de; dmarc=none X-Rspam-User: X-HE-Tag: 1648226939-76872 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 Fri, Mar 25, 2022 at 01:58:42PM +0100, Michal Hocko wrote: > Dang, I have just realized that I have misread the boot log and it has > turned out that a674e48c5443 is covering my situation because the > allocation failure message says: > > Node 0 DMA free:0kB boost:0kB min:0kB low:0kB high:0kB reserved_highatomic:0KB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB writepending:0kB present:636kB managed:0kB mlocked:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB As in your report is from a kernel that does not have a674e48c5443 yet? > > I thought there are only few pages in the managed by the DMA zone. This > is still theoretically possible so I think __GFP_NOWARN makes sense here > but it would require to change the patch description. > > Is this really worth it? In general I think for kernels where we need the pool and can't allocate it, a warning is very useful. We just shouldn't spew it when there is no need for the pool to start with.