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 214C7C433F5 for ; Tue, 21 Dec 2021 09:05:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B20906B0071; Tue, 21 Dec 2021 04:05:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AA8B36B0073; Tue, 21 Dec 2021 04:05:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 94A776B0074; Tue, 21 Dec 2021 04:05:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0207.hostedemail.com [216.40.44.207]) by kanga.kvack.org (Postfix) with ESMTP id 84E656B0071 for ; Tue, 21 Dec 2021 04:05:56 -0500 (EST) Received: from smtpin02.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 4C3958249980 for ; Tue, 21 Dec 2021 09:05:56 +0000 (UTC) X-FDA: 78941219112.02.AF1CA31 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf05.hostedemail.com (Postfix) with ESMTP id D1CAF10002F for ; Tue, 21 Dec 2021 09:05:55 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id D4A5B68B05; Tue, 21 Dec 2021 10:05:52 +0100 (CET) Date: Tue, 21 Dec 2021 10:05:52 +0100 From: Christoph Hellwig To: Logan Gunthorpe Cc: linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Stephen Bates , Christoph Hellwig , Dan Williams , Jason Gunthorpe , Christian =?iso-8859-1?Q?K=F6nig?= , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Jakowski Andrzej , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy , Martin Oliveira , Chaitanya Kulkarni Subject: Re: [PATCH v4 17/23] block: add check when merging zone device pages Message-ID: <20211221090552.GD7949@lst.de> References: <20211117215410.3695-1-logang@deltatee.com> <20211117215410.3695-18-logang@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20211117215410.3695-18-logang@deltatee.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: D1CAF10002F X-Stat-Signature: 4e51ier5w3paiuoe335xs9uioraaf8fw Authentication-Results: imf05.hostedemail.com; dkim=none; dmarc=none; spf=none (imf05.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de X-HE-Tag: 1640077555-588846 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: > +/* > + * Consecutive zone device pages should not be merged into the same sgl > + * or bvec segment with other types of pages or if they belong to different > + * pgmaps. Otherwise getting the pgmap of a given segment is not possible > + * without scanning the entire segment. This helper returns true either if > + * both pages are not zone device pages or both pages are zone device pages > + * with the same pgmap. > + */ > +static inline bool zone_device_pages_are_mergeable(const struct page *a, > + const struct page *b) Merging is only really a use case here. This really checks if they belong to the same pgmap, so I suspect that should be in the name.