From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A4D922ECD3A; Wed, 22 Oct 2025 06:24:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761114292; cv=none; b=dutoeRbKC+wYGaTgAcp5AHyutyIJVTgeHE/c7EbCTlEODxqkNGmmbbA/0QVrmBClctCwAtzLP88jAyNqC4/rOttF9sIRgX/jKg0Wf14yMSP4Tf2vihu0YLDKGx4wMX6pcOaNaMkkgMyfzQm85jZNqw1pbceYhrOYQibHl1vbu4w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761114292; c=relaxed/simple; bh=vHas3sy8prCVLo71319oRvMTTc/fK2RlrePiiW26olw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=ZDo03chbPnaT7nqcNVtzKSjgx6BeNmo8SsgWU8qTXQT3ggupo3nUjBHsGvDQF6EuXZNETrxVscpMNE4LGfEXQ1Oxsr4cZDXgbu0Jew8QcGjasLBytHU6EpRuaPuw59cIjADLfGnri338vhnQQI8nchvAZlhW1Bl5cOfSsUianLI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=RX7a1AXW; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="RX7a1AXW" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; 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=1XhDE1BELRWX5YDOcVl25kQ97WNQSKEMx7NE0+Z0zfs=; b=RX7a1AXWTILfx/vttsD6ASD5QM nm39/Tj4XmpGD53ez9zf4QpAZwF67Zia4CQzhS9732EWS8EPh2m8ojSGgnoJs+ttrmJRmrRTMPhRi jt9Me0ujkGJNrMfLgoTCR5PgmzW3b8SlrnGxZ4pz/+jVDasdZsUWCAqzQ0ae3gmPoSxHkqQ/q19xI RYkBGdEhA6XkBkYrGAoXPT+y9kz1RXrhJ3UCNIW1WFCR3np8xaonuIeoPL7+Mp6mH+7Pnppq8Qvxt gfbhjptNvEJ0BDuMiJWCcyQYvs5SNAKh9t7u6juA0NeJcsmSSGnr1ZY9pemg6FZaqGbLYAb1E/y07 Yqg5E91w==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1vBSHA-00000001eTW-3aoM; Wed, 22 Oct 2025 06:24:48 +0000 Date: Tue, 21 Oct 2025 23:24:48 -0700 From: "hch@infradead.org" To: Qu Wenruo Cc: "hch@infradead.org" , Johannes Thumshirn , WenRuo Qu , "linux-btrfs@vger.kernel.org" , "djwong@kernel.org" , "linux-xfs@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-block@vger.kernel.org" , "linux-mm@kvack.org" , "martin.petersen@oracle.com" , "jack@suse.com" Subject: Re: O_DIRECT vs BLK_FEAT_STABLE_WRITES, was Re: [PATCH] btrfs: never trust the bio from direct IO Message-ID: References: <4f4c468a-ac87-4f54-bc5a-d35058e42dd2@suse.com> <25742d91-f82e-482e-8978-6ab2288569da@wdc.com> <3677cfe8-00cd-466d-b9e3-680c6d6d8c73@gmx.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3677cfe8-00cd-466d-b9e3-680c6d6d8c73@gmx.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Wed, Oct 22, 2025 at 04:47:56PM +1030, Qu Wenruo wrote: > So far it looks like the bounce pages solution is wasting a lot of code for > almost nothing, it's not any better than falling back. That was my expectation, but I wasn't entirely sure from your wording if that's what you measured. > Since we always fallback to buffered IO for checksums, the content should > not change and we can do the submission and checksum calculation in > parallel. Yes. > Already got a prototype, results around 10% improvement inside my VM. > Will fix the bugs related to compression and send an RFC for it. Nice. I've also started looking at my PI backlog for the XFS version.