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 AAA27C433F5 for ; Tue, 14 Dec 2021 16:47:20 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BA8686B0074; Tue, 14 Dec 2021 11:31:39 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B57DB6B0078; Tue, 14 Dec 2021 11:31:39 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A6E3E6B007B; Tue, 14 Dec 2021 11:31:39 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay032.a.hostedemail.com [64.99.140.32]) by kanga.kvack.org (Postfix) with ESMTP id 99E1B6B0074 for ; Tue, 14 Dec 2021 11:31:39 -0500 (EST) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id 633FD604B2 for ; Tue, 14 Dec 2021 16:31:29 +0000 (UTC) X-FDA: 78916940298.04.A2C3690 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf12.hostedemail.com (Postfix) with ESMTP id B95024000C for ; Tue, 14 Dec 2021 16:31:22 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 8628268AFE; Tue, 14 Dec 2021 17:31:24 +0100 (CET) Date: Tue, 14 Dec 2021 17:31:24 +0100 From: Christoph Hellwig To: Baoquan He Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, hch@lst.de, cl@linux.com, John.p.donnelly@oracle.com, kexec@lists.infradead.org, stable@vger.kernel.org, Pekka Enberg , David Rientjes , Joonsoo Kim , Vlastimil Babka Subject: Re: [PATCH v3 5/5] mm/slub: do not create dma-kmalloc if no managed pages in DMA zone Message-ID: <20211214163124.GA21762@lst.de> References: <20211213122712.23805-1-bhe@redhat.com> <20211213122712.23805-6-bhe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211213122712.23805-6-bhe@redhat.com> User-Agent: Mutt/1.5.17 (2007-11-01) Authentication-Results: imf12.hostedemail.com; dkim=none; dmarc=none; spf=none (imf12.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: B95024000C X-Stat-Signature: rswk8puw83ufyic167ezhm3gqbzwissa X-HE-Tag: 1639499482-205610 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, Dec 13, 2021 at 08:27:12PM +0800, Baoquan He wrote: > Dma-kmalloc will be created as long as CONFIG_ZONE_DMA is enabled. > However, it will fail if DMA zone has no managed pages. The failure > can be seen in kdump kernel of x86_64 as below: Please just switch the sr allocation to use GFP_KERNEL without GFP_DMA. The block layer will do the proper bounce buffering underneath for the very unlikely case that we're actually using the single HBA driver that has ISA DMA addressing limitations. Same for the ch drive, btw.