From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F19AE79EA for ; Thu, 7 Aug 2025 02:47:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754534868; cv=none; b=XvaICAeQ0h37FBHd3rnya2D28h7ifGNTC+qMA0jLntoDudixidqewWJ3+IPm1U11oiiQK8V5b8WveJ54ilaKAZkkpRV/J6bolK7/BndQhWGhIZEtpjBji63Gu3Gp9ohJjfsPiJkBOK1VFlh7rhcHmW7+p5H4m0WZ7vCuApTQIB4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754534868; c=relaxed/simple; bh=uTtkPEq2yFmxCcFM/cPem5ZdCduiGqyu/C6uW0UOaZc=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=H19RXMPZI+6AT/50YG/BbsXpM/AZghfl/qiAQ+9DnNQEgOB7fzpoqe5D4gt9lGbbBJdBHB3dsWK205GRnHPJOsObxXM2xECU8uG0lB6ZPcJ3t5vz4L7cOkarCoYv3ywgJBNzGyobVfXKayXeBtnZKQ2tfBPIyDe+qhQkuaMFkZQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pwBV7J5E; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pwBV7J5E" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7AD8DC4CEE7; Thu, 7 Aug 2025 02:47:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754534866; bh=uTtkPEq2yFmxCcFM/cPem5ZdCduiGqyu/C6uW0UOaZc=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=pwBV7J5E4b9ZdLq6jrLdWGFr/R9CR1SwZMqjXpOnX6WPH9o3VcvOZqPJv/t+hinSR DZMoLDfT6q4XB3etQ2EoCZrkBF7hKxPrZ+gVPrc7mMfYKEcK4+Fq1c3gtsKBO8Opap AKhZ9ms5Rbi+zPnH00ykgztByByAFwU6syZVZsumcorFLzyApW6DVD/OISMPLQpoNz YPVGJ6C20b5pS/J7MkIKmHctNuWmpL1ypbD2mz9lpK0A39bPJADWPCeFYKrzzMV4p3 VZwwGJi5qtJo9dCz4wqOU5r9Tym27pItJ7Idr07eE8/IGzf7ghYjQcEWSCZqwk7ury 8RzCcYstVEEMA== Message-ID: Date: Thu, 7 Aug 2025 10:47:43 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, jaegeuk@kernel.org, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH] f2fs: introduce flush_policy sysfs entry To: Zhiguo Niu References: <20250731084700.1230841-1-chao@kernel.org> Content-Language: en-US From: Chao Yu In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 8/7/25 10:16, Zhiguo Niu wrote: > Chao Yu via Linux-f2fs-devel > 于2025年7月31日周四 16:49写道： >> >> 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. >> >> Signed-off-by: Chao Yu >> --- >> Documentation/ABI/testing/sysfs-fs-f2fs | 9 +++++++++ >> fs/f2fs/checkpoint.c | 10 +++++++++- >> fs/f2fs/f2fs.h | 7 +++++++ >> fs/f2fs/sysfs.c | 9 +++++++++ >> 4 files changed, 34 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs >> index bc0e7fefc39d..2fedb44b713b 100644 >> --- a/Documentation/ABI/testing/sysfs-fs-f2fs >> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs >> @@ -883,3 +883,12 @@ Date: June 2025 >> Contact: "Daeho Jeong" >> Description: Control GC algorithm for boost GC. 0: cost benefit, 1: greedy >> Default: 1 >> + >> +What: /sys/fs/f2fs//flush_policy >> +Date: July 2025 >> +Contact: "Chao Yu" >> +Description: Device has different performance for the same flush methods, this node >> + can be used to tune performance by setting different flush methods. >> + >> + policy value description >> + 0x00000001 Use preflush instead of fua during checkpoint >> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c >> index bbe07e3a6c75..10cc27158770 100644 >> --- a/fs/f2fs/checkpoint.c >> +++ b/fs/f2fs/checkpoint.c >> @@ -1419,7 +1419,9 @@ static void commit_checkpoint(struct f2fs_sb_info *sbi, >> f2fs_folio_put(folio, false); >> >> /* submit checkpoint (with barrier if NOBARRIER is not set) */ >> - f2fs_submit_merged_write(sbi, META_FLUSH); >> + f2fs_submit_merged_write(sbi, >> + sbi->flush_policy & BIT(FLUSH_POLICY_CP_NO_FUA) ? >> + META : META_FLUSH); >> } >> >> static inline u64 get_sectors_written(struct block_device *bdev) >> @@ -1606,6 +1608,12 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc) >> f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA); >> stat_cp_time(cpc, CP_TIME_WAIT_LAST_CP); >> >> + if (sbi->flush_policy & BIT(FLUSH_POLICY_CP_NO_FUA)) { >> + err = f2fs_flush_device_cache(sbi); >> + if (err) >> + return err; >> + } > Hi Chao, > sorry for late interruption. > f2fs_flush_device_cache is just used for multi device cases, so this patch will > not be suitable for a single device if the user changes flush_policy > by sysfs, otherwise it > will not use FUA write when committing checkpoint? Is this expected? Zhiguo, I expected to flush primary device as well, so I need to fix this, thanks for catching this. Thanks, > Thanks! >> + >> /* >> * invalidate intermediate page cache borrowed from meta inode which are >> * used for migration of encrypted, verity or compressed inode's blocks. >> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h >> index 5c0ea60e502e..5bba24ca15c8 100644 >> --- a/fs/f2fs/f2fs.h >> +++ b/fs/f2fs/f2fs.h >> @@ -1621,6 +1621,11 @@ struct decompress_io_ctx { >> #define MAX_COMPRESS_LOG_SIZE 8 >> #define MAX_COMPRESS_WINDOW_SIZE(log_size) ((PAGE_SIZE) << (log_size)) >> >> +enum flush_policy { >> + FLUSH_POLICY_CP_NO_FUA, >> + FLUSH_POLICY_MAX, >> +}; >> + >> struct f2fs_sb_info { >> struct super_block *sb; /* pointer to VFS super block */ >> struct proc_dir_entry *s_proc; /* proc entry */ >> @@ -1873,6 +1878,8 @@ struct f2fs_sb_info { >> /* carve out reserved_blocks from total blocks */ >> bool carve_out; >> >> + unsigned int flush_policy; /* flush policy */ >> + >> #ifdef CONFIG_F2FS_FS_COMPRESSION >> struct kmem_cache *page_array_slab; /* page array entry */ >> unsigned int page_array_slab_size; /* default page array slab size */ >> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c >> index f736052dea50..b69015f1dc67 100644 >> --- a/fs/f2fs/sysfs.c >> +++ b/fs/f2fs/sysfs.c >> @@ -852,6 +852,13 @@ static ssize_t __sbi_store(struct f2fs_attr *a, >> return count; >> } >> >> + if (!strcmp(a->attr.name, "flush_policy")) { >> + if (t >= BIT(FLUSH_POLICY_MAX)) >> + return -EINVAL; >> + *ui = (unsigned int)t; >> + return count; >> + } >> + >> if (!strcmp(a->attr.name, "gc_boost_gc_multiple")) { >> if (t < 1 || t > SEGS_PER_SEC(sbi)) >> return -EINVAL; >> @@ -1175,6 +1182,7 @@ F2FS_SBI_GENERAL_RW_ATTR(blkzone_alloc_policy); >> #endif >> F2FS_SBI_GENERAL_RW_ATTR(carve_out); >> F2FS_SBI_GENERAL_RW_ATTR(reserved_pin_section); >> +F2FS_SBI_GENERAL_RW_ATTR(flush_policy); >> >> /* STAT_INFO ATTR */ >> #ifdef CONFIG_F2FS_STAT_FS >> @@ -1371,6 +1379,7 @@ static struct attribute *f2fs_attrs[] = { >> ATTR_LIST(max_read_extent_count), >> ATTR_LIST(carve_out), >> ATTR_LIST(reserved_pin_section), >> + ATTR_LIST(flush_policy), >> NULL, >> }; >> ATTRIBUTE_GROUPS(f2fs); >> -- >> 2.49.0 >> >> >> >> _______________________________________________ >> Linux-f2fs-devel mailing list >> Linux-f2fs-devel@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel