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 3B2F726529E; Mon, 11 Aug 2025 10:52:15 +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=1754909536; cv=none; b=fFeBBY56Y7cWJa1vakS+wQ3aTWMsdeRvFAKU1rYHjzd5i5mqHh/R/P212alUXhG+P8KcqLeg/lTNsEu6iwBArrhEUScgQvj5hPyDgq9byC+eGDd9B4dk9pGgbZE3Znub72Ohpa+DYygXRLHaN/zhi9Wpmvl/IFNJEGrTZ4pSwy4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754909536; c=relaxed/simple; bh=nNhBGgfo5UDY3UdB7sNOLf/9518M0X6GiNtIAdmbeFs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=AClfWHe19Fnsv1u4x4EjvSQQ3d326iS5HWr6WtGKbtjWwPb/e4NvYfIDvKO86vwCewODK2Rn8iZV/uyf6Pr+0wpDMDPHAW43Hhs55trz05F3tTgTWvk0ocnYyKUjk6ChYSMNkkWi3V3au/PajX+ZhLyO1aNzfXBLX0ssdOpGVVY= 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=g8SAFBFU; 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="g8SAFBFU" 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=r0kNG01CA6dOzzsRnPvIcMq2oWocxxH3LcP8Ljz9034=; b=g8SAFBFU7m+GF+PrkhLKmFMoVv aTlPYoUoQxhawI1WRbb6rB+6ky+vo+mzcKjFCLYDo2Wlx3Jn5gnBP9JhbBdUWweYbEkgm7ZXkQeC0 rRRJtqtfZPc49dnFElvG6m0stugCZWJbxnbsdjzlVLhly1tqCHHiY5guJcTS8a5eqVs5SncvdE5WP SkmGvWu9/bUKB8MtNWxlURk1WhT3ykWhV7WPjfGlfEcGVCs5cbgTaglajbm7SUd30A3qQxD1OTBSm o+un9nWU4NtNbgZEPj5Gy/hl9qLx/Fyn/pfIP0/RcLPalLad9zGGNh0Hq7XIqGPB322mXb2bvJH3x AKzFzeiQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1ulQ8U-00000007PQj-3cIg; Mon, 11 Aug 2025 10:52:14 +0000 Date: Mon, 11 Aug 2025 03:52:14 -0700 From: Christoph Hellwig To: Chao Yu Cc: jaegeuk@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org Subject: Re: [PATCH v3] f2fs: introduce flush_policy sysfs entry Message-ID: References: <20250807034838.3829794-1-chao@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@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: <20250807034838.3829794-1-chao@kernel.org> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Aug 07, 2025 at 11:48:38AM +0800, Chao Yu wrote: > This patch introduces a new sysfs entry /sys/fs/f2fs//flush_policy > in order to tune performance of f2fs data flush flow. > > For example, checkpoint will use REQ_FUA to persist CP metadata, however, > some kind device has bad performance on REQ_FUA command, result in that > checkpoint being blocked for long time, w/ this sysfs entry, we can give > an option to use REQ_PREFLUSH command instead of REQ_FUA during checkpoint, > it can help to mitigate long latency of checkpoint. That's and odd place to deal with this. If that's a real issue it should be a block layer tweak to disable FUA, potentially with a quirk entry in the driver to disable it rather than having to touch a file system sysfs attribute.