[PATCH v3] f2fs: introduce discard_io_aware_gran sysfs node

From: Yangtao Li
Date: Wed Jan 04 2023 - 06:40:53 EST


The current discard_io_aware_gran is a fixed value, change it to be
configurable through the sys node.

Signed-off-by: Yangtao Li <frank.li@xxxxxxxx>
---
v3: remove DEFAULT_IO_AWARE_DISCARD_GRANULARITY
Documentation/ABI/testing/sysfs-fs-f2fs | 9 +++++++++
fs/f2fs/f2fs.h | 1 +
fs/f2fs/segment.c | 3 ++-
fs/f2fs/sysfs.c | 13 +++++++++++++
4 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index aaa379bb8a8f..75420c242cc4 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -708,3 +708,12 @@ Description: Support configuring fault injection type, should be
FAULT_LOCK_OP 0x000020000
FAULT_BLKADDR 0x000040000
=================== ===========
+
+What: /sys/fs/f2fs/<disk>/discard_io_aware_gran
+Date: January 2023
+Contact: "Yangtao Li" <frank.li@xxxxxxxx>
+Description: Controls background discard granularity of inner discard thread
+ when is not in idle. Inner thread will not issue discards with size that
+ is smaller than granularity. The unit size is one block(4KB), now only
+ support configuring in range of [0, 512].
+ Default: 512
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 0a24447472db..cf60221d084e 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -409,6 +409,7 @@ struct discard_cmd_control {
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_io_aware_gran; /* minimum discard granularity not be aware of I/O */
unsigned int discard_urgent_util; /* utilization which issue discard proactively */
unsigned int discard_granularity; /* discard granularity */
unsigned int max_ordered_discard; /* maximum discard granularity issued by lba order */
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 34e9dc4df5bb..d988d83108b2 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1059,7 +1059,7 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
dpolicy->granularity = granularity;

dpolicy->max_requests = dcc->max_discard_request;
- dpolicy->io_aware_gran = MAX_PLIST_NUM;
+ dpolicy->io_aware_gran = dcc->discard_io_aware_gran;
dpolicy->timeout = false;

if (discard_type == DPOLICY_BG) {
@@ -2063,6 +2063,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
if (!dcc)
return -ENOMEM;

+ dcc->discard_io_aware_gran = MAX_PLIST_NUM;
dcc->discard_granularity = DEFAULT_DISCARD_GRANULARITY;
dcc->max_ordered_discard = DEFAULT_MAX_ORDERED_DISCARD_GRANULARITY;
if (F2FS_OPTION(sbi).discard_unit == DISCARD_UNIT_SEGMENT)
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 805b632a3af0..e396851a6dd1 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -473,6 +473,17 @@ static ssize_t __sbi_store(struct f2fs_attr *a,
return count;
}

+ if (!strcmp(a->attr.name, "discard_io_aware_gran")) {
+ if (t > MAX_PLIST_NUM)
+ return -EINVAL;
+ if (!f2fs_block_unit_discard(sbi))
+ return -EINVAL;
+ if (t == *ui)
+ return count;
+ *ui = t;
+ return count;
+ }
+
if (!strcmp(a->attr.name, "discard_granularity")) {
if (t == 0 || t > MAX_PLIST_NUM)
return -EINVAL;
@@ -825,6 +836,7 @@ F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, max_discard_request, max_discard_req
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_io_aware_gran, discard_io_aware_gran);
F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, discard_urgent_util, discard_urgent_util);
F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, discard_granularity, discard_granularity);
F2FS_RW_ATTR(DCC_INFO, discard_cmd_control, max_ordered_discard, max_ordered_discard);
@@ -960,6 +972,7 @@ static struct attribute *f2fs_attrs[] = {
ATTR_LIST(min_discard_issue_time),
ATTR_LIST(mid_discard_issue_time),
ATTR_LIST(max_discard_issue_time),
+ ATTR_LIST(discard_io_aware_gran),
ATTR_LIST(discard_urgent_util),
ATTR_LIST(discard_granularity),
ATTR_LIST(max_ordered_discard),
--
2.25.1