[PATCH 2/2] f2fs: add sysfs entries to select the gc policy
From: Namjae Jeon
Date: Wed Jul 31 2013 - 10:33:27 EST
From: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
Add sysfs entries namely gc_long_idle and gc_short_idle to control the
gc policy. Where long idle corresponds to selecting a cost benefit approach,
while short idle corresponds to selecting a greedy approach to garbage
collection. The selection is mutually exclusive one approach will work at
any point.
Signed-off-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
Signed-off-by: Pankaj Kumar <pankaj.km@xxxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-fs-f2fs | 12 +++++++
Documentation/filesystems/f2fs.txt | 8 +++++
fs/f2fs/gc.c | 22 ++++++++++--
fs/f2fs/gc.h | 4 +++
fs/f2fs/super.c | 59 +++++++++++++++++++++++++++++--
5 files changed, 99 insertions(+), 6 deletions(-)
diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs
index 5f44095..96b62ea 100644
--- a/Documentation/ABI/testing/sysfs-fs-f2fs
+++ b/Documentation/ABI/testing/sysfs-fs-f2fs
@@ -19,4 +19,16 @@ Description:
Controls the default sleep time for gc_thread. Time
is in milliseconds.
+What: /sys/fs/f2fs/<disk>/gc_long_idle
+Date: July 2013
+Contact: "Namjae Jeon" <namjae.jeon@xxxxxxxxxxx>
+Description:
+ Controls the selection of gc policy. long_idle is used
+ to select the cost benefit approach for garbage collection.
+What: /sys/fs/f2fs/<disk>/gc_short_idle
+Date: July 2013
+Contact: "Namjae Jeon" <namjae.jeon@xxxxxxxxxxx>
+Description:
+ Controls the selection of gc policy. short_idle is used
+ to select the greedy approach for garbage collection.
diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt
index 2e9e873..06dd5d7 100644
--- a/Documentation/filesystems/f2fs.txt
+++ b/Documentation/filesystems/f2fs.txt
@@ -158,6 +158,14 @@ Files in /sys/fs/f2fs/<devname>
time for the garbage collection thread. Time is
in milliseconds.
+ gc_long_idle This parameter controls the selection of cost
+ benefit approach for garbage collectoin. Writing
+ 1 to this file will select the cost benefit policy.
+
+ gc_short_idle This parameter controls the selection of greedy
+ approach for the garbage collection. Writing 1
+ to this file will select the greedy policy.
+
================================================================================
USAGE
================================================================================
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 60d4f67..af2d9d7 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -106,6 +106,8 @@ int start_gc_thread(struct f2fs_sb_info *sbi)
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->long_idle = gc_th->short_idle = 0;
+
sbi->gc_thread = gc_th;
init_waitqueue_head(&sbi->gc_thread->gc_wait_queue_head);
sbi->gc_thread->f2fs_gc_task = kthread_run(gc_thread_func, sbi,
@@ -130,9 +132,23 @@ void stop_gc_thread(struct f2fs_sb_info *sbi)
sbi->gc_thread = NULL;
}
-static int select_gc_type(int gc_type)
+static int select_gc_type(struct f2fs_gc_kthread *gc_th, int gc_type)
{
- return (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
+ int gc_mode;
+
+ if (gc_th) {
+ if (gc_th->long_idle) {
+ gc_mode = GC_CB;
+ goto out;
+ } else if (gc_th->short_idle) {
+ gc_mode = GC_GREEDY;
+ goto out;
+ }
+ }
+
+ gc_mode = (gc_type == BG_GC) ? GC_CB : GC_GREEDY;
+out:
+ return gc_mode;
}
static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
@@ -145,7 +161,7 @@ static void select_policy(struct f2fs_sb_info *sbi, int gc_type,
p->dirty_segmap = dirty_i->dirty_segmap[type];
p->ofs_unit = 1;
} else {
- p->gc_mode = select_gc_type(gc_type);
+ p->gc_mode = select_gc_type(sbi->gc_thread, gc_type);
p->dirty_segmap = dirty_i->dirty_segmap[DIRTY];
p->ofs_unit = sbi->segs_per_sec;
}
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
index f4bf44c..b2faae5 100644
--- a/fs/f2fs/gc.h
+++ b/fs/f2fs/gc.h
@@ -30,6 +30,10 @@ struct f2fs_gc_kthread {
unsigned int min_sleep_time;
unsigned int max_sleep_time;
unsigned int no_gc_sleep_time;
+
+ /* for changing gc mode */
+ unsigned int long_idle;
+ unsigned int short_idle;
};
struct inode_entry {
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 30de280..3db806b 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -107,6 +107,56 @@ static ssize_t f2fs_sbi_store(struct f2fs_attr *a,
return count;
}
+static ssize_t f2fs_gc_long_idle_store(struct f2fs_attr *a,
+ struct f2fs_sb_info *sbi,
+ const char *buf, size_t count)
+{
+ struct f2fs_gc_kthread *gc_kth = sbi->gc_thread;
+ unsigned long t;
+ ssize_t ret;
+
+ if (!gc_kth)
+ return -EFAULT;
+
+ ret = kstrtoul(skip_spaces(buf), 0, &t);
+ if (ret < 0)
+ return ret;
+
+ if (t == 0)
+ gc_kth->long_idle = 0;
+ else if (t == 1) {
+ gc_kth->long_idle = 1;
+ gc_kth->short_idle = 0;
+ }
+
+ return count;
+}
+
+static ssize_t f2fs_gc_short_idle_store(struct f2fs_attr *a,
+ struct f2fs_sb_info *sbi,
+ const char *buf, size_t count)
+{
+ struct f2fs_gc_kthread *gc_kth = sbi->gc_thread;
+ unsigned long t;
+ ssize_t ret;
+
+ if (!gc_kth)
+ return -EFAULT;
+
+ ret = kstrtoul(skip_spaces(buf), 0, &t);
+ if (ret < 0)
+ return ret;
+
+ if (t == 0)
+ gc_kth->short_idle = 0;
+ else if (t == 1) {
+ gc_kth->short_idle = 1;
+ gc_kth->long_idle = 0;
+ }
+
+ return count;
+}
+
static ssize_t f2fs_attr_show(struct kobject *kobj,
struct attribute *attr, char *buf)
{
@@ -142,21 +192,24 @@ static struct f2fs_attr f2fs_attr_##_name = { \
.offset = offsetof(struct f2fs_gc_kthread, _elname), \
}
-#define F2FS_ATTR(name, mode, show, store) \
-static struct f2fs_attr f2fs_attr_##name = __ATTR(name, mode, show, store)
-
#define F2FS_RW_ATTR(name, elname) \
F2FS_ATTR_OFFSET(name, 0644, f2fs_sbi_show, f2fs_sbi_store, elname)
F2FS_RW_ATTR(gc_min_sleep_time, min_sleep_time);
F2FS_RW_ATTR(gc_max_sleep_time, max_sleep_time);
F2FS_RW_ATTR(gc_no_gc_sleep_time, no_gc_sleep_time);
+F2FS_ATTR_OFFSET(gc_long_idle, 0644, f2fs_sbi_show,
+ f2fs_gc_long_idle_store, long_idle);
+F2FS_ATTR_OFFSET(gc_short_idle, 0644, f2fs_sbi_show,
+ f2fs_gc_short_idle_store, short_idle);
#define ATTR_LIST(name) (&f2fs_attr_##name.attr)
static struct attribute *f2fs_attrs[] = {
ATTR_LIST(gc_min_sleep_time),
ATTR_LIST(gc_max_sleep_time),
ATTR_LIST(gc_no_gc_sleep_time),
+ ATTR_LIST(gc_long_idle),
+ ATTR_LIST(gc_short_idle),
NULL,
};
--
1.7.9.5
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