f2fs: avoid frequent background GC

If there is no victim segments selected by background GC, let's wait
a little bit longer time to collect dirty segments.
By default, let's give 5 minutes.

Reviewed-by: Namjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk.kim@samsung.com>

2 files changed, 9 insertions, 6 deletions

diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 1ca332455ee2..6ed3263eeee8 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -82,9 +82,6 @@ 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;
-                else if (wait_ms == GC_THREAD_NOGC_SLEEP_TIME)
-                        wait_ms = GC_THREAD_MAX_SLEEP_TIME;
-
         } while (!kthread_should_stop());
         return 0;
 }
diff --git a/fs/f2fs/gc.h b/fs/f2fs/gc.h
index 30b2db003acd..2c6a6bd08322 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        10000 /* milliseconds */
-#define GC_THREAD_MAX_SLEEP_TIME        30000
-#define GC_THREAD_NOGC_SLEEP_TIME       10000
+#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 LIMIT_INVALID_BLOCK     40 /* percentage over total user space */
 #define LIMIT_FREE_BLOCK        40 /* percentage over invalid + free space */
 
@@ -58,6 +58,9 @@ static inline block_t limit_free_user_blocks(struct f2fs_sb_info *sbi)
 
 static inline long increase_sleep_time(long wait)
 {
+        if (wait == GC_THREAD_NOGC_SLEEP_TIME)
+                return wait;
+
         wait += GC_THREAD_MIN_SLEEP_TIME;
         if (wait > GC_THREAD_MAX_SLEEP_TIME)
                 wait = GC_THREAD_MAX_SLEEP_TIME;
@@ -66,6 +69,9 @@ static inline long increase_sleep_time(long wait)
 
 static inline long decrease_sleep_time(long wait)
 {
+        if (wait == GC_THREAD_NOGC_SLEEP_TIME)
+                wait = GC_THREAD_MAX_SLEEP_TIME;
+
         wait -= GC_THREAD_MIN_SLEEP_TIME;
         if (wait <= GC_THREAD_MIN_SLEEP_TIME)
                 wait = GC_THREAD_MIN_SLEEP_TIME;