f2fs: sysfs: support discard_io_aware

It gives a way to enable/disable IO aware feature for background
discard, so that we can tune background discard more precisely
based on undiscard condition. e.g. force to disable IO aware if
there are large number of discard extents, and discard IO may
always be interrupted by frequent common IO.

Signed-off-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 36c3cb5479013a30dfe5e73acc2a9f1a37cdde54..4f1d4e636d674b6fe18043f14de4c02f276c1785 100644 (file)
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -740,3 +740,9 @@ Description:        When compress cache is on, it controls cached page
                If cached page percent exceed threshold, then deny caching compress page.
                The value should be in range of (0, 100], by default it was initialized
                as 20(%).
+
+What:          /sys/fs/f2fs/<disk>/discard_io_aware
+Date:          November 2023
+Contact:       "Chao Yu" <chao@kernel.org>
+Description:   It controls to enable/disable IO aware feature for background discard.
+               By default, the value is 1 which indicates IO aware is on.

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 9043cedfa12bacf6e5ffb86f331a13756a2e4694..86a145be4e53790f7b81e56cd5a7d1e383c2a81f 100644 (file)
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -374,6 +374,12 @@ enum {
        MAX_DPOLICY,
 };
 
+enum {
+       DPOLICY_IO_AWARE_DISABLE,       /* force to not be aware of IO */
+       DPOLICY_IO_AWARE_ENABLE,        /* force to be aware of IO */
+       DPOLICY_IO_AWARE_MAX,
+};
+
 struct discard_policy {
        int type;                       /* type of discard */
        unsigned int min_interval;      /* used for candidates exist */
@@ -406,6 +412,7 @@ struct discard_cmd_control {
        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 */
+       unsigned int discard_io_aware;          /* io_aware policy */
        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 f4ffd64b44b2a7abaeeb3b6abfedeb7a21f07900..08e2f44a126496fedc1c596150a49a6ddd7969c2 100644 (file)
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -1172,7 +1172,10 @@ static void __init_discard_policy(struct f2fs_sb_info *sbi,
                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;
+               if (dcc->discard_io_aware == DPOLICY_IO_AWARE_ENABLE)
+                       dpolicy->io_aware = true;
+               else if (dcc->discard_io_aware == DPOLICY_IO_AWARE_DISABLE)
+                       dpolicy->io_aware = false;
                dpolicy->sync = false;
                dpolicy->ordered = true;
                if (utilization(sbi) > dcc->discard_urgent_util) {
@@ -2275,6 +2278,7 @@ static int create_discard_cmd_control(struct f2fs_sb_info *sbi)
        dcc->discard_io_aware_gran = MAX_PLIST_NUM;
        dcc->discard_granularity = DEFAULT_DISCARD_GRANULARITY;
        dcc->max_ordered_discard = DEFAULT_MAX_ORDERED_DISCARD_GRANULARITY;
+       dcc->discard_io_aware = DPOLICY_IO_AWARE_ENABLE;
        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 417fae96890f67bdded952838c43c3d3b799adb1..7099ffa572993377137ab3d63eb70e5a1d5e0aa9 100644 (file)
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -516,6 +516,13 @@ out:
                return count;
        }
 
+       if (!strcmp(a->attr.name, "discard_io_aware")) {
+               if (t >= DPOLICY_IO_AWARE_MAX)
+                       return -EINVAL;
+               *ui = t;
+               return count;
+       }
+
        if (!strcmp(a->attr.name, "migration_granularity")) {
                if (t == 0 || t > sbi->segs_per_sec)
                        return -EINVAL;
@@ -926,6 +933,7 @@ DCC_INFO_GENERAL_RW_ATTR(discard_io_aware_gran);
 DCC_INFO_GENERAL_RW_ATTR(discard_urgent_util);
 DCC_INFO_GENERAL_RW_ATTR(discard_granularity);
 DCC_INFO_GENERAL_RW_ATTR(max_ordered_discard);
+DCC_INFO_GENERAL_RW_ATTR(discard_io_aware);
 
 /* NM_INFO ATTR */
 NM_INFO_RW_ATTR(max_roll_forward_node_blocks, max_rf_node_blocks);
@@ -1074,6 +1082,7 @@ static struct attribute *f2fs_attrs[] = {
        ATTR_LIST(discard_urgent_util),
        ATTR_LIST(discard_granularity),
        ATTR_LIST(max_ordered_discard),
+       ATTR_LIST(discard_io_aware),
        ATTR_LIST(pending_discard),
        ATTR_LIST(gc_mode),
        ATTR_LIST(ipu_policy),