f2fs: introduce gc_urgent mode for background GC
This patch adds a sysfs entry to control urgent mode for background GC.
If this is set, background GC thread conducts GC with gc_urgent_sleep_time
all the time.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
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 84c606f..621da3f 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -130,3 +130,15 @@
Contact: "Chao Yu" <yuchao0@huawei.com>
Description:
Controls current reserved blocks in system.
+
+What: /sys/fs/f2fs/<disk>/gc_urgent
+Date: August 2017
+Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
+Description:
+ Do background GC agressively
+
+What: /sys/fs/f2fs/<disk>/gc_urgent_sleep_time
+Date: August 2017
+Contact: "Jaegeuk Kim" <jaegeuk@kernel.org>
+Description:
+ Controls sleep time of GC urgent mode
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index b8f495a..84f3689 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -210,6 +210,15 @@
gc_idle = 1 will select the Cost Benefit approach
& setting gc_idle = 2 will select the greedy approach.
+ gc_urgent This parameter controls triggering background GCs
+ urgently or not. Setting gc_urgent = 0 [default]
+ makes back to default behavior, while if it is set
+ to 1, background thread starts to do GC by given
+ gc_urgent_sleep_time interval.
+
+ gc_urgent_sleep_time This parameter controls sleep time for gc_urgent.
+ 500 ms is set by default. See above gc_urgent.
+
reclaim_segments This parameter controls the number of prefree
segments to be reclaimed. If the number of prefree
segments is larger than the number of segments
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 620dca4..8da7c14 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -35,9 +35,14 @@
set_freezable();
do {
wait_event_interruptible_timeout(*wq,
- kthread_should_stop() || freezing(current),
+ kthread_should_stop() || freezing(current) ||
+ gc_th->gc_wake,
msecs_to_jiffies(wait_ms));
+ /* give it a try one time */
+ if (gc_th->gc_wake)
+ gc_th->gc_wake = 0;
+
if (try_to_freeze())
continue;
if (kthread_should_stop())
@@ -74,6 +79,11 @@
if (!mutex_trylock(&sbi->gc_mutex))
goto next;
+ if (gc_th->gc_urgent) {
+ wait_ms = gc_th->urgent_sleep_time;
+ goto do_gc;
+ }
+
if (!is_idle(sbi)) {
increase_sleep_time(gc_th, &wait_ms);
mutex_unlock(&sbi->gc_mutex);
@@ -84,7 +94,7 @@
decrease_sleep_time(gc_th, &wait_ms);
else
increase_sleep_time(gc_th, &wait_ms);
-
+do_gc:
stat_inc_bggc_count(sbi);
/* if return value is not zero, no victim was selected */
@@ -115,11 +125,14 @@
goto out;
}
+ gc_th->urgent_sleep_time = DEF_GC_THREAD_URGENT_SLEEP_TIME;
gc_th->min_sleep_time = DEF_GC_THREAD_MIN_SLEEP_TIME;
gc_th->max_sleep_time = DEF_GC_THREAD_MAX_SLEEP_TIME;
gc_th->no_gc_sleep_time = DEF_GC_THREAD_NOGC_SLEEP_TIME;
gc_th->gc_idle = 0;
+ gc_th->gc_urgent = 0;
+ gc_th->gc_wake= 0;
sbi->gc_thread = gc_th;
init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
index a993967..57a9000 100644
--- a/fs/f2fs/gc.h
+++ b/fs/f2fs/gc.h
@@ -13,6 +13,7 @@
* whether IO subsystem is idle
* or not
*/
+#define DEF_GC_THREAD_URGENT_SLEEP_TIME 500 /* 500 ms */
#define DEF_GC_THREAD_MIN_SLEEP_TIME 30000 /* milliseconds */
#define DEF_GC_THREAD_MAX_SLEEP_TIME 60000
#define DEF_GC_THREAD_NOGC_SLEEP_TIME 300000 /* wait 5 min */
@@ -27,12 +28,15 @@
wait_queue_head_t gc_wait_queue_head;
/* for gc sleep time */
+ unsigned int urgent_sleep_time;
unsigned int min_sleep_time;
unsigned int max_sleep_time;
unsigned int no_gc_sleep_time;
/* for changing gc mode */
unsigned int gc_idle;
+ unsigned int gc_urgent;
+ unsigned int gc_wake;
};
struct gc_inode_list {
diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c
index 3d6bbdb..c40e5d2 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -156,6 +156,10 @@
if (!strcmp(a->attr.name, "iostat_enable") && *ui == 0)
f2fs_reset_iostat(sbi);
+ if (!strcmp(a->attr.name, "gc_urgent") && t == 1 && sbi->gc_thread) {
+ sbi->gc_thread->gc_wake = 1;
+ wake_up_interruptible_all(&sbi->gc_thread->gc_wait_queue_head);
+ }
return count;
}
@@ -235,10 +239,13 @@
.id = _id, \
}
+F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_urgent_sleep_time,
+ urgent_sleep_time);
F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_min_sleep_time, min_sleep_time);
F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_max_sleep_time, max_sleep_time);
F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_no_gc_sleep_time, no_gc_sleep_time);
F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_idle, gc_idle);
+F2FS_RW_ATTR(GC_THREAD, f2fs_gc_kthread, gc_urgent, gc_urgent);
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(RESERVED_BLOCKS, f2fs_sb_info, reserved_blocks, reserved_blocks);
@@ -275,10 +282,12 @@
#define ATTR_LIST(name) (&f2fs_attr_##name.attr)
static struct attribute *f2fs_attrs[] = {
+ ATTR_LIST(gc_urgent_sleep_time),
ATTR_LIST(gc_min_sleep_time),
ATTR_LIST(gc_max_sleep_time),
ATTR_LIST(gc_no_gc_sleep_time),
ATTR_LIST(gc_idle),
+ ATTR_LIST(gc_urgent),
ATTR_LIST(reclaim_segments),
ATTR_LIST(max_small_discards),
ATTR_LIST(batched_trim_sections),