[PATCH 2/2] f2fs: expose discard related parameters in sysfs

From: Jaegeuk Kim
Date: Tue Jan 25 2022 - 15:23:32 EST


From: Konstantin Vyshetsky <vkon@xxxxxxxxxx>

This patch exposes max_discard_request, min_discard_issue_time,
mid_discard_issue_time, and max_discard_issue_time in sysfs. This will
allow the user to fine tune discard operations.

Signed-off-by: Konstantin Vyshetsky <vkon@xxxxxxxxxx>
Signed-off-by: Jaegeuk Kim <jaegeuk@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-fs-f2fs | 27 +++++++++++++++++++++++++
fs/f2fs/sysfs.c | 8 ++++++++
2 files changed, 35 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 2416b03ff283..87d3884c90ea 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -98,6 +98,33 @@ Description: Controls the issue rate of discard commands that consist of small
checkpoint is triggered, and issued during the checkpoint.
By default, it is disabled with 0.

+What: /sys/fs/f2fs/<disk>/max_discard_request
+Date: December 2021
+Contact: "Konstantin Vyshetsky" <vkon@xxxxxxxxxx>
+Description: Controls the number of discards a thread will issue at a time.
+ Higher number will allow the discard thread to finish its work
+ faster, at the cost of higher latency for incomming I/O.
+
+What: /sys/fs/f2fs/<disk>/min_discard_issue_time
+Date: December 2021
+Contact: "Konstantin Vyshetsky" <vkon@xxxxxxxxxx>
+Description: Controls the interval the discard thread will wait between
+ issuing discard requests when there are discards to be issued and
+ no I/O aware interruptions occur.
+
+What: /sys/fs/f2fs/<disk>/mid_discard_issue_time
+Date: December 2021
+Contact: "Konstantin Vyshetsky" <vkon@xxxxxxxxxx>
+Description: Controls the interval the discard thread will wait between
+ issuing discard requests when there are discards to be issued and
+ an I/O aware interruption occurs.
+
+What: /sys/fs/f2fs/<disk>/max_discard_issue_time
+Date: December 2021
+Contact: "Konstantin Vyshetsky" <vkon@xxxxxxxxxx>
+Description: Controls the interval the discard thread will wait when there are
+ no discard operations to be issued.
+
What: /sys/fs/f2fs/<disk>/discard_granularity
Date: July 2017
Contact: "Chao Yu" <yuchao0@xxxxxxxxxx>
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 2bccdaedfb00..281bc0133ee6 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -716,6 +716,10 @@ F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_idle, gc_mode);
F2FS_RW_ATTR(F2FS_SBI, f2fs_sb_info, gc_urgent, gc_mode);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, reclaim_segments, rec_prefree_segments);
F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, max_small_discards, max_discards);
+F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, max_discard_request, max_discard_request);
+F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, min_discard_issue_time, min_discard_issue_time);
+F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, mid_discard_issue_time, mid_discard_issue_time);
+F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, max_discard_issue_time, max_discard_issue_time);
F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, discard_granularity, discard_granularity);
F2FS_RW_ATTR(RESERVED_BLOCKS, f2fs_sb_info, reserved_blocks, reserved_blocks);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, batched_trim_sections, trim_sections);
@@ -832,6 +836,10 @@ static struct attribute *f2fs_attrs[] = {
ATTR_LIST(reclaim_segments),
ATTR_LIST(main_blkaddr),
ATTR_LIST(max_small_discards),
+ ATTR_LIST(max_discard_request),
+ ATTR_LIST(min_discard_issue_time),
+ ATTR_LIST(mid_discard_issue_time),
+ ATTR_LIST(max_discard_issue_time),
ATTR_LIST(discard_granularity),
ATTR_LIST(pending_discard),
ATTR_LIST(batched_trim_sections),
--
2.35.0.rc0.227.g00780c9af4-goog