[PATCH 1/2] f2fs: move discard parameters into discard_cmd_control

[PATCH 1/2] f2fs: move discard parameters into discard_cmd_control

[Jaegeuk Kim]

From: Konstantin Vyshetsky <vkon@google.com>

This patch unifies parameters related to how often discard is issued and
how many requests go out at the same time by placing them in
discard_cmd_control. The move will allow the parameters to be modified
in the future without relying on hard-coded values.

Signed-off-by: Konstantin Vyshetsky <vkon@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/f2fs.h    |  4 ++++
 fs/f2fs/segment.c | 22 +++++++++++++---------
 2 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 8178a9152e49..63c90416364b 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -398,6 +398,10 @@ struct discard_cmd_control {
 	struct mutex cmd_lock;
 	unsigned int nr_discards;		/* # of discards in the list */
 	unsigned int max_discards;		/* max. discards to be issued */
+	unsigned int max_discard_request;	/* max. discard request per round */
+	unsigned int min_discard_issue_time;	/* min. interval between discard issue */
+	unsigned int mid_discard_issue_time;	/* mid. interval between discard issue */
+	unsigned int max_discard_issue_time;	/* max. interval between discard issue */
 	unsigned int discard_granularity;	/* discard granularity */
 	unsigned int undiscard_blks;		/* # of undiscard blocks */
 	unsigned int next_pos;			/* next discard position */
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 216538b57331..56211e201d51 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1156,14 +1156,14 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
 	dpolicy->ordered = false;
 	dpolicy->granularity = granularity;
 
-	dpolicy->max_requests = DEF_MAX_DISCARD_REQUEST;
+	dpolicy->max_requests = dcc->max_discard_request;
 	dpolicy->io_aware_gran = MAX_PLIST_NUM;
 	dpolicy->timeout = false;
 
 	if (discard_type == DPOLICY_BG) {
-		dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
-		dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME;
-		dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
+		dpolicy->min_interval = dcc->min_discard_issue_time;
+		dpolicy->mid_interval = dcc->mid_discard_issue_time;
+		dpolicy->max_interval = dcc->max_discard_issue_time;
 		dpolicy->io_aware = true;
 		dpolicy->sync = false;
 		dpolicy->ordered = true;
@@ -1171,12 +1171,12 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
 			dpolicy->granularity = 1;
 			if (atomic_read(&dcc->discard_cmd_cnt))
 				dpolicy->max_interval =
-					DEF_MIN_DISCARD_ISSUE_TIME;
+					dcc->min_discard_issue_time;
 		}
 	} else if (discard_type == DPOLICY_FORCE) {
-		dpolicy->min_interval = DEF_MIN_DISCARD_ISSUE_TIME;
-		dpolicy->mid_interval = DEF_MID_DISCARD_ISSUE_TIME;
-		dpolicy->max_interval = DEF_MAX_DISCARD_ISSUE_TIME;
+		dpolicy->min_interval = dcc->min_discard_issue_time;
+		dpolicy->mid_interval = dcc->mid_discard_issue_time;
+		dpolicy->max_interval = dcc->max_discard_issue_time;
 		dpolicy->io_aware = false;
 	} else if (discard_type == DPOLICY_FSTRIM) {
 		dpolicy->io_aware = false;
@@ -1781,7 +1781,7 @@ static int issue_discard_thread(void *data)
 	struct discard_cmd_control *dcc = SM_I(sbi)->dcc_info;
 	wait_queue_head_t *q = &dcc->discard_wait_queue;
 	struct discard_policy dpolicy;
-	unsigned int wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
+	unsigned int wait_ms = dcc->min_discard_issue_time;
 	int issued;
 
 	set_freezable();
@@ -2180,6 +2180,10 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
 	atomic_set(&dcc->discard_cmd_cnt, 0);
 	dcc->nr_discards = 0;
 	dcc->max_discards = MAIN_SEGS(sbi) << sbi->log_blocks_per_seg;
+	dcc->max_discard_request = DEF_MAX_DISCARD_REQUEST;
+	dcc->min_discard_issue_time = DEF_MIN_DISCARD_ISSUE_TIME;
+	dcc->mid_discard_issue_time = DEF_MID_DISCARD_ISSUE_TIME;
+	dcc->max_discard_issue_time = DEF_MAX_DISCARD_ISSUE_TIME;
 	dcc->undiscard_blks = 0;
 	dcc->next_pos = 0;
 	dcc->root = RB_ROOT_CACHED;
-- 
2.35.0.rc0.227.g00780c9af4-goog

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

[Jaegeuk Kim]

From: Konstantin Vyshetsky <vkon@google.com>

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@google.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 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@google.com>
+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@google.com>
+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@google.com>
+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@google.com>
+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@huawei.com>
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

Re: [f2fs-dev] [PATCH 1/2] f2fs: move discard parameters into discard_cmd_control

[Chao Yu]

On 2022/1/26 4:22, Jaegeuk Kim wrote:
> From: Konstantin Vyshetsky <vkon@google.com>
> 
> This patch unifies parameters related to how often discard is issued and
> how many requests go out at the same time by placing them in
> discard_cmd_control. The move will allow the parameters to be modified
> in the future without relying on hard-coded values.
> 
> Signed-off-by: Konstantin Vyshetsky <vkon@google.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,

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

[Chao Yu]

On 2022/1/26 4:22, Jaegeuk Kim wrote:
> From: Konstantin Vyshetsky <vkon@google.com>
> 
> 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@google.com>
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,