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 4DAB5C28D13 for ; Mon, 22 Aug 2022 12:09:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234932AbiHVMJX (ORCPT ); Mon, 22 Aug 2022 08:09:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234960AbiHVMJS (ORCPT ); Mon, 22 Aug 2022 08:09:18 -0400 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EECF39BBF for ; Mon, 22 Aug 2022 05:09:15 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id 5985C1FE82; Mon, 22 Aug 2022 12:09:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1661170154; 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=BQf11C2SztSHaAc1fCCEYoFCW50NZH5mzh9dLltQPVs=; b=p4lTmBdyCOljd88Lou0ApPiNTcrg55ISrXyy2Z2lgw6d95MbM2hP18vHea0UGA5CSG1Fju 7wgNx7ZgREOAm0apcWAR9/w46u0ucAGD/W+pMXpik/faroXcSl+gpHFdH+Ac/ev+kpgFsw IdmcniYJyPob4UtDLTruYq88xgtW5xk= Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 36B9F13523; Mon, 22 Aug 2022 12:09:14 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id gm7eC+pxA2MlQQAAMHmgww (envelope-from ); Mon, 22 Aug 2022 12:09:14 +0000 Date: Mon, 22 Aug 2022 14:09:13 +0200 From: Michal Hocko To: Christoph Hellwig Cc: iommu@lists.linux.dev, Marek Szyprowski , Robin Murphy , David Rientjes , linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] dma-pool: limit DMA and DMA32 zone size pools Message-ID: References: <20220817060647.1032426-1-hch@lst.de> <20220817060647.1032426-4-hch@lst.de> <20220821104416.GC30530@lst.de> <20220822111447.GA8935@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220822111447.GA8935@lst.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 22-08-22 13:14:47, Christoph Hellwig wrote: > On Mon, Aug 22, 2022 at 10:41:01AM +0200, Michal Hocko wrote: > > ZONE_DMA existance is not runtime controlable (at least on x86). > > This is more about ZONE_DMA32 that can disappear if all memory is > inside ZONE_DMA. That is highly unusual (but still possible) with a > tiny x86-style ZONE_DMA, but can happen with a larger one other > architectures. OK, so you are worried about configurations that lack ZONE_DMA32 because that memory range is covered by ZONE_DMA? I thought though simply do not have CONFIG_ZONE_DMA32. Or am I wrong here? -- Michal Hocko SUSE Labs