From nobody Sun Oct 5 18:12:41 2025 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 3E9611F5823 for ; Thu, 31 Jul 2025 08:47:04 +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=1753951625; cv=none; b=fHY0nuqMyLyvZ6fKlLzmrTmh+xanCZOlV0S7+7ZlLEBsYQTHKBYIDkGKzm8/BZTeSnX3UH4xNP9TKuCBb/sT2+zEANQDnSNGt0zT0x+HR2y9+UsSX9Q0lr5B8cosYMwFn5bG1hj3QGHFA45cggntD3Jl6ZaKhKhM472CKnAUH8Q= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753951625; c=relaxed/simple; bh=+fnwHN6QmOM/bnMzHAE1c3XypnhU/CSThAyt5NMS4Lc=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=WwviDhzS8dK2q8Ft5j1e7U+SeDaUjYT3Nvds1AbLKXQ3HTTBHdxGVkr32KGJJSrVsgYopaLln6Hzunqeu5G4Z0gFtB4Q3SsUWcws/vEshdU64mb41FtKL6mqqEeG7vJq8BJmAxibn4IoSuGe1AURyiQXFFrCzVy0NtXZOTSbitc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=e0QylBOI; 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="e0QylBOI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B3076C4CEEF; Thu, 31 Jul 2025 08:47:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753951624; bh=+fnwHN6QmOM/bnMzHAE1c3XypnhU/CSThAyt5NMS4Lc=; h=From:To:Cc:Subject:Date:From; b=e0QylBOISbcQcFdVw/z5zJaYjsiHJZKCB1DULdJno3c6QD44iWBPlU//WWpR5S3g5 dJVgUjIIKWAfyR/6z4wLNpRsVfZ3uUvL3wfvGcurMN3uP6IYmyuRf3MX2bHhhOly4p ZDPWAQytOw06eEawx0TejyqBYPVy6qz84hUeI+v/cAWoiXhswdVOnNqze76kFK4Pce WdFpfvFQEU8NgD1uOdXIC+5Rp0OFHUohVuoJguhV2Q5E4fArGyQdW+ynw5oBf7J/fp J/LRGMgD77IPHEYZgw6u8h+Osps4MftZCPZnaCLpf8USgwOYc9Mtpyn//4VkuKyTmR KCIiry5ZIJLdA== From: Chao Yu To: jaegeuk@kernel.org Cc: linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, Chao Yu Subject: [PATCH] f2fs: introduce flush_policy sysfs entry Date: Thu, 31 Jul 2025 16:47:00 +0800 Message-ID: <20250731084700.1230841-1-chao@kernel.org> X-Mailer: git-send-email 2.50.1.552.g942d659e1b-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" 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/te= sting/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 *sb= i, f2fs_folio_put(folio, false); =20 /* 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); } =20 static inline u64 get_sectors_written(struct block_device *bdev) @@ -1606,6 +1608,12 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, s= truct cp_control *cpc) f2fs_wait_on_all_pages(sbi, F2FS_WB_CP_DATA); stat_cp_time(cpc, CP_TIME_WAIT_LAST_CP); =20 + if (sbi->flush_policy & BIT(FLUSH_POLICY_CP_NO_FUA)) { + err =3D f2fs_flush_device_cache(sbi); + if (err) + return err; + } + /* * 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)) =20 +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; =20 + 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; } =20 + if (!strcmp(a->attr.name, "flush_policy")) { + if (t >=3D BIT(FLUSH_POLICY_MAX)) + return -EINVAL; + *ui =3D (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); =20 /* STAT_INFO ATTR */ #ifdef CONFIG_F2FS_STAT_FS @@ -1371,6 +1379,7 @@ static struct attribute *f2fs_attrs[] =3D { ATTR_LIST(max_read_extent_count), ATTR_LIST(carve_out), ATTR_LIST(reserved_pin_section), + ATTR_LIST(flush_policy), NULL, }; ATTRIBUTE_GROUPS(f2fs); --=20 2.49.0