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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 DA88AC433DB for ; Mon, 8 Feb 2021 23:02:19 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 60D2964E82 for ; Mon, 8 Feb 2021 23:02:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 60D2964E82 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 B0CC86B0005; Mon, 8 Feb 2021 18:02:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id ABD186B006C; Mon, 8 Feb 2021 18:02:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9ABBC6B006E; Mon, 8 Feb 2021 18:02:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0078.hostedemail.com [216.40.44.78]) by kanga.kvack.org (Postfix) with ESMTP id 83B576B0005 for ; Mon, 8 Feb 2021 18:02:18 -0500 (EST) Received: from smtpin24.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 4BD8B6C09 for ; Mon, 8 Feb 2021 23:02:18 +0000 (UTC) X-FDA: 77796625956.24.pipe21_3b10c9127602 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin24.hostedemail.com (Postfix) with ESMTP id 2F4E31A4A0 for ; Mon, 8 Feb 2021 23:02:18 +0000 (UTC) X-HE-Tag: pipe21_3b10c9127602 X-Filterd-Recvd-Size: 2131 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf20.hostedemail.com (Postfix) with ESMTP for ; Mon, 8 Feb 2021 23:02:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.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; bh=ccjx+Lijh4w6XmegtzS4AwX0coPJ3byCzA/5A3ypCMs=; b=Eq5xQyZ3RnrfGEUXJgtN1U2NfM 23ycIPPjgY2rsBKIyZbE7iMj1Zbo4Hdg0JX2NmrsJ9YV3pU8XR3PM6dP5g2hr5nVVJvPfAzlMPZqU QGSduesaxBf0pW0vOf5WeBzIIWFGnKD3LDaEOraFYO3uyweDaRjHYOBuTEeILhAHSWQ2Jo8AY0mIK w7LG++KtJ/Oq+eoxak22x40o7ZVEFBrveQprGt8MUhdwJeRkY9AJ/UmKnllxUD1OwyrGTlo+3weMu Ypum0CkZheHzhTKU1iQu8Vb2h5EYi36sjG+oBzyPBK3GrD7DFS0mG/1eM8d2T2g06dvRArgpAH+N0 IeQSJsDg==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1l9FXh-006ec2-Ck; Mon, 08 Feb 2021 23:02:06 +0000 Date: Mon, 8 Feb 2021 23:02:05 +0000 From: Matthew Wilcox To: Jens Axboe Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, hch@infradead.org, akpm@linux-foundation.org Subject: Re: [PATCH 1/3] mm: provide filemap_range_needs_writeback() helper Message-ID: <20210208230205.GV308988@casper.infradead.org> References: <20210208221829.17247-1-axboe@kernel.dk> <20210208221829.17247-2-axboe@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210208221829.17247-2-axboe@kernel.dk> 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 Mon, Feb 08, 2021 at 03:18:27PM -0700, Jens Axboe wrote: > + rcu_read_lock(); > + xas_for_each(&xas, head, max) { > + if (xas_retry(&xas, head)) > + continue; > + if (xa_is_value(head)) > + continue; > + page = find_subpage(head, xas.xa_index); > + if (PageDirty(page) || PageLocked(page) || PageWriteback(page)) > + break; > + page = NULL; > + } > + rcu_read_unlock(); There's no need to find the sub-page for any of these three conditions -- the bit will be set on the head page.