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Date: Mon, 7 Aug 2017 20:09:27 -0700
From: Jaegeuk Kim <jaegeuk@...nel.org>
To: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [PATCH 2/2 v2] f2fs: introduce gc_urgent mode for background GC
Change log from v1:
- update Documentation.
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.
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
---
Documentation/ABI/testing/sysfs-fs-f2fs | 12 ++++++++++++
Documentation/filesystems/f2fs.txt | 9 +++++++++
fs/f2fs/gc.c | 17 +++++++++++++++--
fs/f2fs/gc.h | 4 ++++
fs/f2fs/sysfs.c | 9 +++++++++
5 files changed, 49 insertions(+), 2 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index c579ce5e0ef5..11b7f4ebea7c 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -139,3 +139,15 @@ Date: June 2017
Contact: "Chao Yu" <yuchao0@...wei.com>
Description:
Controls current reserved blocks in system.
+
+What: /sys/fs/f2fs/<disk>/gc_urgent
+Date: August 2017
+Contact: "Jaegeuk Kim" <jaegeuk@...nel.org>
+Description:
+ Do background GC agressively
+
+What: /sys/fs/f2fs/<disk>/gc_urgent_sleep_time
+Date: August 2017
+Contact: "Jaegeuk Kim" <jaegeuk@...nel.org>
+Description:
+ Controls sleep time of GC urgent mode
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index b8f495a8b67d..84f36896766c 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -210,6 +210,15 @@ Files in /sys/fs/f2fs/<devname>
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 620dca443b29..8da7c14a9d29 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -35,9 +35,14 @@ static int gc_thread_func(void *data)
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 @@ static int gc_thread_func(void *data)
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 @@ static int gc_thread_func(void *data)
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 @@ int start_gc_thread(struct f2fs_sb_info *sbi)
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 a993967dcdb9..57a9000ce3af 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 @@ struct f2fs_gc_kthread {
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 4e5a95e9e666..b769a3d776de 100644
--- a/fs/f2fs/sysfs.c
+++ b/fs/f2fs/sysfs.c
@@ -161,6 +161,10 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
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;
}
@@ -240,10 +244,13 @@ static struct f2fs_attr f2fs_attr_##_name = { \
.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(DCC_INFO, discard_cmd_control, discard_granularity, discard_granularity);
@@ -281,10 +288,12 @@ F2FS_FEATURE_RO_ATTR(inode_checksum, FEAT_INODE_CHECKSUM);
#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(discard_granularity),
--
2.13.0.rc1.294.g07d810a77f-goog
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