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=-0.6 required=3.0 tests=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 BD3A6C33CA9 for ; Mon, 13 Jan 2020 21:58:25 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7FF112187F for ; Mon, 13 Jan 2020 21:58:25 +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="QhjG5sZ7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7FF112187F 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 079088E0006; Mon, 13 Jan 2020 16:58:25 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 02AC78E0003; Mon, 13 Jan 2020 16:58:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E82668E0006; Mon, 13 Jan 2020 16:58:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0247.hostedemail.com [216.40.44.247]) by kanga.kvack.org (Postfix) with ESMTP id D2CAE8E0003 for ; Mon, 13 Jan 2020 16:58:24 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id 750A9181AC9BF for ; Mon, 13 Jan 2020 21:58:24 +0000 (UTC) X-FDA: 76373975328.22.grade45_650680132ab45 X-HE-Tag: grade45_650680132ab45 X-Filterd-Recvd-Size: 2681 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) by imf19.hostedemail.com (Postfix) with ESMTP for ; Mon, 13 Jan 2020 21:58:14 +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=vIM78U2tiWS9Y/ZT/+KZFKq5Yv/4AD1q7UnORAYypVA=; b=QhjG5sZ73yT68+nsT+PJK7boT 5hGKSj9h0MWjy4zOpkZ99sx5F6bMnW4oeh/BVRiYN7rRSA5+LDcu4UCW4ylznEE2T+LXn6e7l0h3v Wk/kRBrV2qeyieT7kIa2lL9X5D/SVPWk8lvc1U6nfVa8mcU0kp19XDbP/87FSMlP7A+H445fZlN8l 5uPAOyAkMVsLHkA2Wbswv6mGE1BGhr0mjdBHjwmSWONgFNHiDjm9hUy8ne2zu+8AfRc6SOpDyFXFv vPFy5BBfjcF4YapnTJ3IUrvylWDHRrrdixB/pAlaPyYUgfzCNGdwD5g+fI0AfTp9fabFTNFVZFiD6 LH5vvu3jA==; Received: from willy by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1ir7it-0001Om-5J; Mon, 13 Jan 2020 21:58:11 +0000 Date: Mon, 13 Jan 2020 13:58:11 -0800 From: Matthew Wilcox To: Chris Mason Cc: "linux-xfs@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "jlayton@kernel.org" , "hch@infradead.org" , Jens Axboe Subject: Re: [RFC 0/8] Replacing the readpages a_op Message-ID: <20200113215811.GA18216@bombadil.infradead.org> References: <20200113153746.26654-1-willy@infradead.org> <6CA4CD96-0812-4261-8FF9-CD28AA2EC38A@fb.com> <20200113174008.GB332@bombadil.infradead.org> <15C84CC9-3196-441D-94DE-F3FD7AC364F0@fb.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <15C84CC9-3196-441D-94DE-F3FD7AC364F0@fb.com> X-Bogosity: Ham, tests=bogofilter, spamicity=0.000657, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Mon, Jan 13, 2020 at 06:00:52PM +0000, Chris Mason wrote: > This is true, I didn't explain that part well ;) Depending on > compression etc we might end up poking the xarray inside the actual IO > functions, but the main difference is that btrfs is building a single > bio. You're moving the plug so you'll merge into single bio, but I'd > rather build 2MB bios than merge them. Why don't we store a bio pointer inside the plug? You're opencoding that, iomap is opencoding that, and I bet there's a dozen other places where we pass a bio around. Then blk_finish_plug can submit the bio.