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 X-Spam-Level: X-Spam-Status: No, score=-9.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E2955C4338F for ; Wed, 25 Aug 2021 11:15:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 510A26108E for ; Wed, 25 Aug 2021 11:15:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 510A26108E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id B48576B006C; Wed, 25 Aug 2021 07:15:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AF85A8D0001; Wed, 25 Aug 2021 07:15:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9E7A36B0072; Wed, 25 Aug 2021 07:15:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0204.hostedemail.com [216.40.44.204]) by kanga.kvack.org (Postfix) with ESMTP id 819116B006C for ; Wed, 25 Aug 2021 07:15:23 -0400 (EDT) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 26FAF18ED0 for ; Wed, 25 Aug 2021 11:15:23 +0000 (UTC) X-FDA: 78513346926.10.B42D0F3 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf16.hostedemail.com (Postfix) with ESMTP id B1959F00009B for ; Wed, 25 Aug 2021 11:15:22 +0000 (UTC) Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (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 362FD200F2; Wed, 25 Aug 2021 11:15:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_rsa; t=1629890121; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JsTZ/9+VRszmlL6hS/sFGVn+Amn3Nh4I4j0bZJL/75s=; b=I7Yi38O5i1rcyp1b3zu0aSxtw2cF3Go7OkwlsISIti7iULIxygNwNF0BH36F2+avkbLNcW 06YUDL+y1Hbvft7P8mvdvOug3JHSgTatWoeMMjAU6Kx57OmI+805Z/qH6eqDuglFihBtQJ CNQ9ji0e3uopyLcJZU5kVtj7OSQqX1U= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.cz; s=susede2_ed25519; t=1629890121; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JsTZ/9+VRszmlL6hS/sFGVn+Amn3Nh4I4j0bZJL/75s=; b=A3w6EnRWXBALysZo9aIw4XjrVtAuedgCl1SGMlGblXmqQ2/TW5TK15Z3OuRoWQj96Fsrp8 vyntj+rs4FdH9vBQ== Received: from imap1.suse-dmz.suse.de (imap1.suse-dmz.suse.de [192.168.254.73]) (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 imap1.suse-dmz.suse.de (Postfix) with ESMTPS id F408413732; Wed, 25 Aug 2021 11:15:20 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap1.suse-dmz.suse.de with ESMTPSA id JNBiOkgmJmH7GwAAGKfGzw (envelope-from ); Wed, 25 Aug 2021 11:15:20 +0000 Message-ID: Date: Wed, 25 Aug 2021 13:15:20 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.0.1 Subject: Re: [PATCH v1 02/14] mm: remove extra ZONE_DEVICE struct page refcount Content-Language: en-US To: Alex Sierra , akpm@linux-foundation.org, Felix.Kuehling@amd.com, linux-mm@kvack.org, rcampbell@nvidia.com, linux-ext4@vger.kernel.org, linux-xfs@vger.kernel.org Cc: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, hch@lst.de, jgg@nvidia.com, jglisse@redhat.com References: <20210825034828.12927-1-alex.sierra@amd.com> <20210825034828.12927-3-alex.sierra@amd.com> From: Vlastimil Babka In-Reply-To: <20210825034828.12927-3-alex.sierra@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: B1959F00009B Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=I7Yi38O5; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=A3w6EnRW; dmarc=none; spf=pass (imf16.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.29 as permitted sender) smtp.mailfrom=vbabka@suse.cz X-Rspamd-Server: rspam01 X-Stat-Signature: a79n91jmkmb3g1saitf7dszx8odnnoee X-HE-Tag: 1629890122-833912 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 8/25/21 05:48, Alex Sierra wrote: > From: Ralph Campbell > > ZONE_DEVICE struct pages have an extra reference count that complicates the > code for put_page() and several places in the kernel that need to check the > reference count to see that a page is not being used (gup, compaction, > migration, etc.). Clean up the code so the reference count doesn't need to > be treated specially for ZONE_DEVICE. That's certainly welcome. I just wonder what was the reason to use 1 in the first place and why it's no longer necessary?