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Tue, 12 Aug 2025 06:28:51 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id DE6BDC4CEF5; Tue, 12 Aug 2025 06:28:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754980131; bh=La7H9eByYagCohgqxw2G3+7zgFCfw7Yo597djXDnUI8=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=a1k9fuZqk/kOMkIEp11qlXl3Qx+u0W/KFGDziAfY78Q72ClFmLm+POlw50Vfogvg8 OhOItv0BpS/V/TYbh8m0oYOUIpkD9iIDYOyZ3/dCbdRg08xd5GnUZkwP+7dwQZKZ4e ZvjubE22oGFfuVufiZx1AYnla3xjP5RTk1fAhNNgx2MyBvtULuXgp3pQ5kP1SKyP/I spePuE4VbfxV41b4eGC2cNvgP+gl8RI1sWVm8e93WjJ2zYXwQV4F6Vl+Df2snQKwPo 4q7JXvVCL70drl/JoFl9KiLHO8R+ZnYn/zjESEsscFgi9Bt6w68NPO0ZUlkRoJtURr RwNEAlbN4FNRg== Message-ID: Date: Tue, 12 Aug 2025 14:28:46 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird To: Christoph Hellwig References: <20250807034838.3829794-1-chao@kernel.org> Content-Language: en-US In-Reply-To: X-Headers-End: 1uliVK-00051N-JJ Subject: Re: [f2fs-dev] [PATCH v3] f2fs: introduce flush_policy sysfs entry X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Chao Yu via Linux-f2fs-devel Reply-To: Chao Yu Cc: linux-block@vger.kernel.org, jaegeuk@kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net On 8/11/25 18:52, Christoph Hellwig wrote: > 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. Okay, it makes sense to control how FUA be handled inside block layer, so let's drop this patch. BTW, I suffered extremely long latency of checkpoint which may block every update operations when testing generic/299 w/ mode=lfs mount option in qemu, then I propose to use PREFLUSH instead of FUA to resolve this issue. "F2FS-fs (vdc): checkpoint was blocked for 24495 ms" I just realize that using cache=directsync option in qemu can avoid FUA hang issue, anyway, let me test more w/ this option. Thanks, _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel