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| author | Chao Yu <yuchao0@huawei.com> | 2017-08-07 23:09:56 +0800 |
|---|---|---|
| committer | Jaegeuk Kim <jaegeuk@kernel.org> | 2017-08-21 15:55:07 -0700 |
| commit | 969d1b180d987c2be02de890d0fff0f66a0e80de (patch) | |
| tree | 0e5f7dcc846d75bf54ad3205c50c85180c7f93ae /Documentation/ABI | |
| parent | f24b150a63b208f4437efc7dc7a42954363641ca (diff) | |
| download | lwn-969d1b180d987c2be02de890d0fff0f66a0e80de.tar.gz lwn-969d1b180d987c2be02de890d0fff0f66a0e80de.zip | |
f2fs: introduce discard_granularity sysfs entry
Commit d618ebaf0aa8 ("f2fs: enable small discard by default") enables
f2fs to issue 4K size discard in real-time discard mode. However, issuing
smaller discard may cost more lifetime but releasing less free space in
flash device. Since f2fs has ability of separating hot/cold data and
garbage collection, we can expect that small-sized invalid region would
expand soon with OPU, deletion or garbage collection on valid datas, so
it's better to delay or skip issuing smaller size discards, it could help
to reduce overmuch consumption of IO bandwidth and lifetime of flash
storage.
This patch makes f2fs selectng 64K size as its default minimal
granularity, and issue discard with the size which is not smaller than
minimal granularity. Also it exposes discard granularity as sysfs entry
for configuration in different scenario.
Jaegeuk Kim:
We must issue all the accumulated discard commands when fstrim is called.
So, I've added pend_list_tag[] to indicate whether we should issue the
commands or not. If tag sets P_ACTIVE or P_TRIM, we have to issue them.
P_TRIM is set once at a time, given fstrim trigger.
In addition, issue_discard_thread is calling too much due to the number of
discard commands remaining in the pending list. I added a timer to control
it likewise gc_thread.
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-fs-f2fs | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs index 621da3fc56c5..11b7f4ebea7c 100644 --- a/Documentation/ABI/testing/sysfs-fs-f2fs +++ b/Documentation/ABI/testing/sysfs-fs-f2fs @@ -57,6 +57,15 @@ Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> Description: Controls the issue rate of small discard commands. +What: /sys/fs/f2fs/<disk>/discard_granularity +Date: July 2017 +Contact: "Chao Yu" <yuchao0@huawei.com> +Description: + Controls discard granularity of inner discard thread, inner thread + will not issue discards with size that is smaller than granularity. + The unit size is one block, now only support configuring in range + of [1, 512]. + What: /sys/fs/f2fs/<disk>/max_victim_search Date: January 2014 Contact: "Jaegeuk Kim" <jaegeuk.kim@samsung.com> |