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 1B624C433F5 for ; Tue, 14 Dec 2021 10:28:25 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 356FD6B0071; Tue, 14 Dec 2021 05:28:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3071A6B0072; Tue, 14 Dec 2021 05:28:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1F6206B0074; Tue, 14 Dec 2021 05:28:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0172.hostedemail.com [216.40.44.172]) by kanga.kvack.org (Postfix) with ESMTP id 0CA216B0071 for ; Tue, 14 Dec 2021 05:28:15 -0500 (EST) Received: from smtpin15.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id BD1C2180DD58B for ; Tue, 14 Dec 2021 10:28:04 +0000 (UTC) X-FDA: 78916024488.15.3D9834A Received: from gentwo.de (gentwo.de [161.97.139.209]) by imf03.hostedemail.com (Postfix) with ESMTP id 0759D20012 for ; Tue, 14 Dec 2021 10:28:03 +0000 (UTC) Received: by gentwo.de (Postfix, from userid 1001) id E26D1B0024C; Tue, 14 Dec 2021 11:28:01 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by gentwo.de (Postfix) with ESMTP id DC483B00038; Tue, 14 Dec 2021 11:28:01 +0100 (CET) Date: Tue, 14 Dec 2021 11:28:01 +0100 (CET) From: Christoph Lameter X-X-Sender: cl@gentwo.de To: Vlastimil Babka cc: Baoquan He , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, hch@lst.de, John.p.donnelly@oracle.com, kexec@lists.infradead.org, stable@vger.kernel.org, Pekka Enberg , David Rientjes , Joonsoo Kim Subject: Re: [PATCH v3 5/5] mm/slub: do not create dma-kmalloc if no managed pages in DMA zone In-Reply-To: Message-ID: References: <20211213122712.23805-1-bhe@redhat.com> <20211213122712.23805-6-bhe@redhat.com> <20211213134319.GA997240@odroid> <20211214053253.GB2216@MiWiFi-R3L-srv> User-Agent: Alpine 2.22 (DEB 394 2020-01-19) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 0759D20012 X-Stat-Signature: fgd8rfkj1txkprkuk36uqufg7zc9955f Authentication-Results: imf03.hostedemail.com; dkim=none; spf=none (imf03.hostedemail.com: domain of cl@gentwo.org has no SPF policy when checking 161.97.139.209) smtp.mailfrom=cl@gentwo.org; dmarc=none X-HE-Tag: 1639477683-455276 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 Tue, 14 Dec 2021, Vlastimil Babka wrote: > If doesn't feel right to me to fix (or rather workaround) this on the level > of kmalloc caches just because the current reports come from there. If we > decide it's acceptable for kdump kernel to return !ZONE_DMA memory for > GFP_DMA requests, then it should apply at the page allocator level for all > allocations, not just kmalloc(). > > Also you mention above you'd prefer ZONE_DMA32 memory, while chances are > this approach of using KMALLOC_NORMAL caches will end up giving you > ZONE_NORMAL. On the page allocator level it would be much easier to > implement a fallback from non-populated ZONE_DMA to ZONE_DMA32 specifically. Well this only works if the restrictions on the physical memory addresses of each platform make that possible.