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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 9618FC43603 for ; Tue, 10 Dec 2019 18:58:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 451BC207FF for ; Tue, 10 Dec 2019 18:58:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="S3lrVAOK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 451BC207FF Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BD64A6B2DCF; Tue, 10 Dec 2019 13:58:25 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B873F6B2DD0; Tue, 10 Dec 2019 13:58:25 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A9DC56B2DD1; Tue, 10 Dec 2019 13:58:25 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 91F8C6B2DCF for ; Tue, 10 Dec 2019 13:58:25 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with SMTP id 58B05180AD83A for ; Tue, 10 Dec 2019 18:58:25 +0000 (UTC) X-FDA: 76250142570.13.dad99_2c47b3cf8bc5c X-HE-Tag: dad99_2c47b3cf8bc5c X-Filterd-Recvd-Size: 2787 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Tue, 10 Dec 2019 18:58:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=zfXhVy9B767K7H4PjJR005yREJ5bgu9ZcNoGeacGpfc=; b=S3lrVAOKD9e+RcqNq2Fj62ubQ fCLdabp/oSuJ+lKtkHlU4SqFGFLm6aCe4lds9k77TBkwFA2dHT6E9vtJqk5Bb7pS3lg48xufiNdCs TV7xTTypMs7dnguFN2N6FHqSo+B5omY+Fz53XCSRVHhv036SWsRVggz1zvl929afJnQDdspgnH3R0 KYjq2RtAtkKT5teTkOmfiDb8ieMGiF8V35f0752VD10Q0Mq7oaHqiefUrNLzja1alz+vbVbCjdZr6 lx6TcgVuIu2x0XXKShicKEg+jvVjjUX1dNNSCNc5LIWWQX4B7ogQaE8e2UVxWSpiyBXNGqIlPV+GU TUmtoEG5Q==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1ieki6-0001vC-17; Tue, 10 Dec 2019 18:58:14 +0000 Date: Tue, 10 Dec 2019 10:58:13 -0800 From: Matthew Wilcox To: Jens Axboe Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org Subject: Re: [PATCH 3/5] mm: make buffered writes work with RWF_UNCACHED Message-ID: <20191210185813.GK32169@bombadil.infradead.org> References: <20191210162454.8608-1-axboe@kernel.dk> <20191210162454.8608-4-axboe@kernel.dk> <20191210165532.GJ32169@bombadil.infradead.org> <721d8d7e-9e24-bded-a3c0-fa5bf433e129@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <721d8d7e-9e24-bded-a3c0-fa5bf433e129@kernel.dk> User-Agent: Mutt/1.12.1 (2019-06-15) X-Bogosity: Ham, tests=bogofilter, spamicity=0.003029, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Dec 10, 2019 at 10:02:18AM -0700, Jens Axboe wrote: > On 12/10/19 9:55 AM, Matthew Wilcox wrote: > > On Tue, Dec 10, 2019 at 09:24:52AM -0700, Jens Axboe wrote: > >> +/* > >> + * Start writeback on the pages in pgs[], and then try and remove those pages > >> + * from the page cached. Used with RWF_UNCACHED. > >> + */ > >> +void write_drop_cached_pages(struct page **pgs, struct address_space *mapping, > >> + unsigned *nr) > > > > It would seem more natural to use a pagevec instead of pgs/nr. > > I did look into that, but they are intertwined with LRU etc. I > deliberately avoided the LRU on the read side, as it adds noticeable > overhead and gains us nothing since the pages will be dropped agian. I agree the LRU uses them, but they're used in all kinds of places where we need to batch pages, eg truncate, munlock.