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f2fs: give an option to enable in-place-updates during fsync to users

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If user wrote F2FS_IPU_FSYNC:4 in /sys/fs/f2fs/ipu_policy, f2fs_sync_file
only starts to try in-place-updates.
And, if the number of dirty pages is over /sys/fs/f2fs/min_fsync_blocks, it
keeps out-of-order manner. Otherwise, it triggers in-place-updates.

This may be used by storage showing very high random write performance.

For example, it can be used when,

Seq. writes (Data) + wait + Seq. writes (Node)

is pretty much slower than,

Rand. writes (Data)

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
This commit is contained in:
Jaegeuk Kim
2014-09-10 16:53:02 -07:00
parent a7ffdbe22c
commit c1ce1b02bb
7 changed files with 33 additions and 10 deletions
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9
Documentation/filesystems/f2fs.txt
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@@ -194,13 +194,20 @@ Files in /sys/fs/f2fs/<devname>
updates in f2fs. There are five policies:
0: F2FS_IPU_FORCE, 1: F2FS_IPU_SSR,
2: F2FS_IPU_UTIL, 3: F2FS_IPU_SSR_UTIL,
4: F2FS_IPU_DISABLE.
4: F2FS_IPU_FSYNC, 5: F2FS_IPU_DISABLE.
min_ipu_util This parameter controls the threshold to trigger
in-place-updates. The number indicates percentage
of the filesystem utilization, and used by
F2FS_IPU_UTIL and F2FS_IPU_SSR_UTIL policies.
min_fsync_blocks This parameter controls the threshold to trigger
in-place-updates when F2FS_IPU_FSYNC mode is set.
The number indicates the number of dirty pages
when fsync needs to flush on its call path. If
the number is less than this value, it triggers
in-place-updates.
max_victim_search This parameter controls the number of trials to
find a victim segment when conducting SSR and
cleaning operations. The default value is 4096