This patch introduces a new sysfs entry /sys/fs/f2fs/<disk>/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 <[email protected]> --- v2: - use __submit_flush_wait() instead of f2fs_flush_device_cache() to just flush primary device cache Documentation/ABI/testing/sysfs-fs-f2fs | 9 +++++++++ fs/f2fs/checkpoint.c | 11 ++++++++++- fs/f2fs/f2fs.h | 7 +++++++ fs/f2fs/sysfs.c | 9 +++++++++ 4 files changed, 35 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" <[email protected]> Description: Control GC algorithm for boost GC. 0: cost benefit, 1: greedy Default: 1 + +What: /sys/fs/f2fs/<disk>/flush_policy +Date: July 2025 +Contact: "Chao Yu" <[email protected]> +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 db3831f7f2f5..fafa2156732d 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) @@ -1594,6 +1596,13 @@ static int do_checkpoint(struct f2fs_sb_info *sbi, struct cp_control *cpc) __set_cp_next_pack(sbi); + /* flush device cache to make sure last cp pack can be persisted */ + if (sbi->flush_policy & BIT(FLUSH_POLICY_CP_NO_FUA)) { + err = __submit_flush_wait(sbi, sbi->sb->s_bdev); + if (err) + return err; + } + /* * redirty superblock if metadata like node page or inode cache is * updated during writing checkpoint. diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index 46be7560548c..5db5eba4cbd7 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -1594,6 +1594,11 @@ 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 */ @@ -1845,6 +1850,8 @@ 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 [email protected] https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
