Re: [PATCH] f2fs: introduce max_order_discard sysfs node

From: Chao Yu
Date: Tue Oct 25 2022 - 03:06:25 EST


On 2022/10/21 18:28, Yangtao Li wrote:
The current max_order_discard is a fixed value,

max_ordered_discard?

change it to be configurable through the sys node.

Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
---
Documentation/ABI/testing/sysfs-fs-f2fs | 6 ++++++
fs/f2fs/f2fs.h | 3 +++
fs/f2fs/segment.c | 3 ++-
fs/f2fs/sysfs.c | 11 +++++++++++
4 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 11ce4a8bdacd..8faef2078a7a 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -99,6 +99,12 @@ 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_order_discard
+Date: October 2022
+Contact: "Yangtao Li" <frank.li@xxxxxxxx>
+Description: Controls the maximum ordered discard, the unit size is one block(4KB).
+ By default, it is disabled with 16.

By default, it is disabled with 16

Set it to 16 by default?

Thanks,

+
What: /sys/fs/f2fs/<disk>/max_discard_request
Date: December 2021
Contact: "Konstantin Vyshetsky" <vkon@xxxxxxxxxx>
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index c444f3f86608..070dee37b915 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -330,6 +330,8 @@ struct discard_entry {
/* default discard granularity of inner discard thread, unit: block count */
#define DEFAULT_DISCARD_GRANULARITY 16
+/* default maximum discard granularity of ordered discard, unit: block count */
+#define DEFAULT_MAX_ORDER_DISCARD_GRANULARITY 16
/* max discard pend list number */
#define MAX_PLIST_NUM 512
@@ -409,6 +411,7 @@ struct discard_cmd_control {
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 max_order_discard; /* maximum discard granularity issued by lba order */
unsigned int undiscard_blks; /* # of undiscard blocks */
unsigned int next_pos; /* next discard position */
atomic_t issued_discard; /* # of issued discard */
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index acf3d3fa4363..921ec17a40ce 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1448,7 +1448,7 @@ static int __issue_discard_cmd(struct f2fs_sb_info *sbi,
if (i + 1 < dpolicy->granularity)
break;
- if (i < DEFAULT_DISCARD_GRANULARITY && dpolicy->ordered)
+ if (i < dcc->max_order_discard && dpolicy->ordered)
return __issue_discard_cmd_orderly(sbi, dpolicy);
pend_list = &dcc->pend_list[i];
@@ -2046,6 +2046,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
return -ENOMEM;
dcc->discard_granularity = DEFAULT_DISCARD_GRANULARITY;
+ dcc->max_order_discard = DEFAULT_MAX_ORDER_DISCARD_GRANULARITY;
if (F2FS_OPTION(sbi).discard_unit == DISCARD_UNIT_SEGMENT)
dcc->discard_granularity = sbi->blocks_per_seg;
else if (F2FS_OPTION(sbi).discard_unit == DISCARD_UNIT_SECTION)
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 555849d4c744..81f628aed2e5 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -487,6 +487,15 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
return count;
}
+ if (!strcmp(a->attr.name, "max_order_discard")) {
+ if (t == 0 || t > MAX_PLIST_NUM)
+ return -EINVAL;
+ if (!f2fs_block_unit_discard(sbi))
+ return -EINVAL;
+ *ui = t;
+ return count;
+ }
+
if (!strcmp(a->attr.name, "migration_granularity")) {
if (t == 0 || t > sbi->segs_per_sec)
return -EINVAL;
@@ -801,6 +810,7 @@ F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, min_discard_issue_time, min_discard_
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(DCC_INFO, discard_cmd_control, max_order_discard, max_order_discard);
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);
F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy);
@@ -931,6 +941,7 @@ static struct attribute *f2fs_attrs[] = {
ATTR_LIST(mid_discard_issue_time),
ATTR_LIST(max_discard_issue_time),
ATTR_LIST(discard_granularity),
+ ATTR_LIST(max_order_discard),
ATTR_LIST(pending_discard),
ATTR_LIST(batched_trim_sections),
ATTR_LIST(ipu_policy),