Hi, Namjae, Agreed. How about this?
Chang log from v1:
o change timings - min 30s, max 60s, nogc 5 min
o remove nonreachable routine
o consider NOGC_SLEEP_TIME in increate/decrease_sleep_time
From 806e344624414fcf9fc87f6193265859027d51b5 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk....@samsung.com>
Date: Wed, 24 Apr 2013 13:00:14 +0900
Subject: [PATCH] f2fs: avoid frequent background GC
Cc: linux-fsde...@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-f2fs-de...@lists.sourceforge.net
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.
Signed-off-by: Jaegeuk Kim <jaegeuk....@samsung.com>
---
fs/f2fs/gc.c | 3 ---
fs/f2fs/gc.h | 12 +++++++++---
2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 1ca3324..6ed3263 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 30b2db0..2c6a6bd 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;
--
1.8.1.3.566.gaa39828
--
Jaegeuk Kim
Samsung
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