f2fs: add sysfs support for controlling the gc_thread

Add sysfs entries to control the timing parameters for
f2fs gc thread.

Various Sysfs options introduced are:
gc_min_sleep_time: Min Sleep time for GC in ms
gc_max_sleep_time: Max Sleep time for GC in ms
gc_no_gc_sleep_time: Default Sleep time for GC in ms

Cc: Gu Zheng <guz.fnst@cn.fujitsu.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Pankaj Kumar <pankaj.km@samsung.com>
Reviewed-by: Gu Zheng <guz.fnst@cn.fujitsu.com>
[Jaegeuk Kim: fix an umount bug and some minor changes]
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

4 files changed, 157 insertions, 20 deletions

diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 78777cdb89de..63813befdd82 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -430,6 +430,10 @@ struct f2fs_sb_info {
 #endif
         unsigned int last_victim[2];            /* last victim segment # */
         spinlock_t stat_lock;                   /* lock for stat operations */
+
+        /* For sysfs suppport */
+        struct kobject s_kobj;
+        struct completion s_kobj_unregister;
 };
 
 /*
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 35f9b1a196aa..60d4f674efa7 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -29,10 +29,11 @@ static struct kmem_cache *winode_slab;
 static int gc_thread_func(void *data)
 {
         struct f2fs_sb_info *sbi = data;
+        struct f2fs_gc_kthread *gc_th = sbi->gc_thread;
         wait_queue_head_t *wq = &sbi->gc_thread->gc_wait_queue_head;
         long wait_ms;
 
-        wait_ms = GC_THREAD_MIN_SLEEP_TIME;
+        wait_ms = gc_th->min_sleep_time;
 
         do {
                 if (try_to_freeze())
@@ -45,7 +46,7 @@ static int gc_thread_func(void *data)
                         break;
 
                 if (sbi->sb->s_writers.frozen >= SB_FREEZE_WRITE) {
-                        wait_ms = GC_THREAD_MAX_SLEEP_TIME;
+                        wait_ms = increase_sleep_time(gc_th, wait_ms);
                         continue;
                 }
 
@@ -66,15 +67,15 @@ static int gc_thread_func(void *data)
                         continue;
 
                 if (!is_idle(sbi)) {
-                        wait_ms = increase_sleep_time(wait_ms);
+                        wait_ms = increase_sleep_time(gc_th, wait_ms);
                         mutex_unlock(&sbi->gc_mutex);
                         continue;
                 }
 
                 if (has_enough_invalid_blocks(sbi))
-                        wait_ms = decrease_sleep_time(wait_ms);
+                        wait_ms = decrease_sleep_time(gc_th, wait_ms);
                 else
-                        wait_ms = increase_sleep_time(wait_ms);
+                        wait_ms = increase_sleep_time(gc_th, wait_ms);
 
 #ifdef CONFIG_F2FS_STAT_FS
                 sbi->bg_gc++;
@@ -82,7 +83,7 @@ static int gc_thread_func(void *data)
 
                 /* if return value is not zero, no victim was selected */
                 if (f2fs_gc(sbi))
-                        wait_ms = GC_THREAD_NOGC_SLEEP_TIME;
+                        wait_ms = gc_th->no_gc_sleep_time;
         } while (!kthread_should_stop());
         return 0;
 }
@@ -101,6 +102,10 @@ int start_gc_thread(struct f2fs_sb_info *sbi)
                 goto out;
         }
 
+        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;
+
         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,
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
index 2c6a6bd08322..f4bf44c9deda 100644
--- a/fs/f2fs/gc.h
+++ b/fs/f2fs/gc.h
@@ -13,9 +13,9 @@
                                                  * whether IO subsystem is idle
                                                  * or not
                                                  */
-#define GC_THREAD_MIN_SLEEP_TIME        30000   /* milliseconds */
-#define GC_THREAD_MAX_SLEEP_TIME        60000
-#define GC_THREAD_NOGC_SLEEP_TIME       300000  /* wait 5 min */
+#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 */
 #define LIMIT_INVALID_BLOCK     40 /* percentage over total user space */
 #define LIMIT_FREE_BLOCK        40 /* percentage over invalid + free space */
 
@@ -25,6 +25,11 @@
 struct f2fs_gc_kthread {
         struct task_struct *f2fs_gc_task;
         wait_queue_head_t gc_wait_queue_head;
+
+        /* for gc sleep time */
+        unsigned int min_sleep_time;
+        unsigned int max_sleep_time;
+        unsigned int no_gc_sleep_time;
 };
 
 struct inode_entry {
@@ -56,25 +61,25 @@ static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi)
         return (long)(reclaimable_user_blocks * LIMIT_FREE_BLOCK) / 100;
 }
 
-static inline long increase_sleep_time(long wait)
+static inline long increase_sleep_time(struct f2fs_gc_kthread *gc_th, long wait)
 {
-        if (wait == GC_THREAD_NOGC_SLEEP_TIME)
+        if (wait == gc_th->no_gc_sleep_time)
                 return wait;
 
-        wait += GC_THREAD_MIN_SLEEP_TIME;
-        if (wait > GC_THREAD_MAX_SLEEP_TIME)
-                wait = GC_THREAD_MAX_SLEEP_TIME;
+        wait += gc_th->min_sleep_time;
+        if (wait > gc_th->max_sleep_time)
+                wait = gc_th->max_sleep_time;
         return wait;
 }
 
-static inline long decrease_sleep_time(long wait)
+static inline long decrease_sleep_time(struct f2fs_gc_kthread *gc_th, long wait)
 {
-        if (wait == GC_THREAD_NOGC_SLEEP_TIME)
-                wait = GC_THREAD_MAX_SLEEP_TIME;
+        if (wait == gc_th->no_gc_sleep_time)
+                wait = gc_th->max_sleep_time;
 
-        wait -= GC_THREAD_MIN_SLEEP_TIME;
-        if (wait <= GC_THREAD_MIN_SLEEP_TIME)
-                wait = GC_THREAD_MIN_SLEEP_TIME;
+        wait -= gc_th->min_sleep_time;
+        if (wait <= gc_th->min_sleep_time)
+                wait = gc_th->min_sleep_time;
         return wait;
 }
 
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 70dbb313a7ca..e161a24fbf39 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -23,17 +23,21 @@
 #include <linux/exportfs.h>
 #include <linux/blkdev.h>
 #include <linux/f2fs_fs.h>
+#include <linux/kobject.h>
+#include <linux/sysfs.h>
 
 #include "f2fs.h"
 #include "node.h"
 #include "segment.h"
 #include "xattr.h"
+#include "gc.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/f2fs.h>
 
 static struct proc_dir_entry *f2fs_proc_root;
 static struct kmem_cache *f2fs_inode_cachep;
+static struct kset *f2fs_kset;
 
 enum {
         Opt_gc_background,
@@ -59,6 +63,111 @@ static match_table_t f2fs_tokens = {
         {Opt_err, NULL},
 };
 
+/* Sysfs support for f2fs */
+struct f2fs_attr {
+        struct attribute attr;
+        ssize_t (*show)(struct f2fs_attr *, struct f2fs_sb_info *, char *);
+        ssize_t (*store)(struct f2fs_attr *, struct f2fs_sb_info *,
+                         const char *, size_t);
+        int offset;
+};
+
+static ssize_t f2fs_sbi_show(struct f2fs_attr *a,
+                        struct f2fs_sb_info *sbi, char *buf)
+{
+        struct f2fs_gc_kthread *gc_kth = sbi->gc_thread;
+        unsigned int *ui;
+
+        if (!gc_kth)
+                return -EINVAL;
+
+        ui = (unsigned int *)(((char *)gc_kth) + a->offset);
+
+        return snprintf(buf, PAGE_SIZE, "%u\n", *ui);
+}
+
+static ssize_t f2fs_sbi_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;
+        unsigned int *ui;
+        ssize_t ret;
+
+        if (!gc_kth)
+                return -EINVAL;
+
+        ui = (unsigned int *)(((char *)gc_kth) + a->offset);
+
+        ret = kstrtoul(skip_spaces(buf), 0, &t);
+        if (ret < 0)
+                return ret;
+        *ui = t;
+        return count;
+}
+
+static ssize_t f2fs_attr_show(struct kobject *kobj,
+                                struct attribute *attr, char *buf)
+{
+        struct f2fs_sb_info *sbi = container_of(kobj, struct f2fs_sb_info,
+                                                                s_kobj);
+        struct f2fs_attr *a = container_of(attr, struct f2fs_attr, attr);
+
+        return a->show ? a->show(a, sbi, buf) : 0;
+}
+
+static ssize_t f2fs_attr_store(struct kobject *kobj, struct attribute *attr,
+                                                const char *buf, size_t len)
+{
+        struct f2fs_sb_info *sbi = container_of(kobj, struct f2fs_sb_info,
+                                                                        s_kobj);
+        struct f2fs_attr *a = container_of(attr, struct f2fs_attr, attr);
+
+        return a->store ? a->store(a, sbi, buf, len) : 0;
+}
+
+static void f2fs_sb_release(struct kobject *kobj)
+{
+        struct f2fs_sb_info *sbi = container_of(kobj, struct f2fs_sb_info,
+                                                                s_kobj);
+        complete(&sbi->s_kobj_unregister);
+}
+
+#define F2FS_ATTR_OFFSET(_name, _mode, _show, _store, _elname) \
+static struct f2fs_attr f2fs_attr_##_name = {                   \
+        .attr = {.name = __stringify(_name), .mode = _mode },   \
+        .show   = _show,                                        \
+        .store  = _store,                                       \
+        .offset = offsetof(struct f2fs_gc_kthread, _elname),    \
+}
+
+#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);
+
+#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),
+        NULL,
+};
+
+static const struct sysfs_ops f2fs_attr_ops = {
+        .show   = f2fs_attr_show,
+        .store  = f2fs_attr_store,
+};
+
+static struct kobj_type f2fs_ktype = {
+        .default_attrs  = f2fs_attrs,
+        .sysfs_ops      = &f2fs_attr_ops,
+        .release        = f2fs_sb_release,
+};
+
 void f2fs_msg(struct super_block *sb, const char *level, const char *fmt, ...)
 {
         struct va_format vaf;
@@ -229,6 +338,7 @@ static void f2fs_put_super(struct super_block *sb)
                 remove_proc_entry("segment_info", sbi->s_proc);
                 remove_proc_entry(sb->s_id, f2fs_proc_root);
         }
+        kobject_del(&sbi->s_kobj);
 
         f2fs_destroy_stats(sbi);
         stop_gc_thread(sbi);
@@ -243,6 +353,8 @@ static void f2fs_put_super(struct super_block *sb)
         destroy_segment_manager(sbi);
 
         kfree(sbi->ckpt);
+        kobject_put(&sbi->s_kobj);
+        wait_for_completion(&sbi->s_kobj_unregister);
 
         sb->s_fs_info = NULL;
         brelse(sbi->raw_super_buf);
@@ -818,6 +930,13 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
                                         "the device does not support discard");
         }
 
+        sbi->s_kobj.kset = f2fs_kset;
+        init_completion(&sbi->s_kobj_unregister);
+        err = kobject_init_and_add(&sbi->s_kobj, &f2fs_ktype, NULL,
+                                                        "%s", sb->s_id);
+        if (err)
+                goto fail;
+
         return 0;
 fail:
         stop_gc_thread(sbi);
@@ -892,6 +1011,9 @@ static int __init init_f2fs_fs(void)
         err = create_checkpoint_caches();
         if (err)
                 goto fail;
+        f2fs_kset = kset_create_and_add("f2fs", NULL, fs_kobj);
+        if (!f2fs_kset)
+                goto fail;
         err = register_filesystem(&f2fs_fs_type);
         if (err)
                 goto fail;
@@ -910,6 +1032,7 @@ static void __exit exit_f2fs_fs(void)
         destroy_gc_caches();
         destroy_node_manager_caches();
         destroy_inodecache();
+        kset_unregister(f2fs_kset);
 }
 
 module_init(init_f2fs_fs)