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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A4344C433EF for ; Fri, 25 Mar 2022 12:58:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359204AbiCYNAV (ORCPT ); Fri, 25 Mar 2022 09:00:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46880 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242241AbiCYNAU (ORCPT ); Fri, 25 Mar 2022 09:00:20 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65B0770916 for ; Fri, 25 Mar 2022 05:58:46 -0700 (PDT) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 2567F210DD; Fri, 25 Mar 2022 12:58:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1648213125; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=j1OTytgc37TnxYn/42F/JXOrrT0mgLkreFQ2GEEDzWE=; b=WckXdQMHBOwB6P7CFtPU3xE9SzUK9jNqYJfHOWAjWFyikgp5efNUPSKu8ux8xwturW4DOb pCuTKhJsl2/ItW6dfv8/Dm2iYQP7tizc1/zw3pOTBA2e+M1tIj9tKltwoLd8S6s/ButTT8 QO3R+unU+hCvR+Bxi6JGEOxwWZsQzOM= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 0A144A3B82; Fri, 25 Mar 2022 12:58:45 +0000 (UTC) Date: Fri, 25 Mar 2022 13:58:42 +0100 From: Michal Hocko To: Andrew Morton , Christoph Hellwig , Baoquan He Cc: 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: References: <20220325122559.14251-1-mhocko@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220325122559.14251-1-mhocko@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 25-03-22 13:25:59, Michal Hocko wrote: > From: Michal Hocko > > we have a system complainging about order-5 allocation for the DMA pool. > This is something that a674e48c5443 ("dma/pool: create dma atomic pool > only if dma zone has managed pages") has already tried to achieve but I > do not think it went all the way to have it covered completely. In this > particular case has_managed_dma() will not work because: > [ 0.678539][ T0] Initmem setup node 0 [mem 0x0000000000001000-0x000000027dffffff] > [ 0.686316][ T0] On node 0, zone DMA: 1 pages in unavailable ranges > [ 0.687093][ T0] On node 0, zone DMA32: 36704 pages in unavailable ranges > [ 0.694278][ T0] On node 0, zone Normal: 53252 pages in unavailable ranges > [ 0.701257][ T0] On node 0, zone Normal: 8192 pages in unavailable ranges 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 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? > > The allocation failure on the DMA zone shouldn't be really critical for > the system operation so just silence the warning instead. > > Signed-off-by: Michal Hocko > --- > kernel/dma/pool.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c > index 4d40dcce7604..1bf6de398986 100644 > --- a/kernel/dma/pool.c > +++ b/kernel/dma/pool.c > @@ -205,7 +205,7 @@ static int __init dma_atomic_pool_init(void) > ret = -ENOMEM; > if (has_managed_dma()) { > atomic_pool_dma = __dma_atomic_pool_init(atomic_pool_size, > - GFP_KERNEL | GFP_DMA); > + GFP_KERNEL | GFP_DMA | __GFP_NOWARN); > if (!atomic_pool_dma) > ret = -ENOMEM; > } > -- > 2.30.2 -- Michal Hocko SUSE Labs