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| author | Jens Axboe <jens.axboe@oracle.com> | 2010-05-17 12:51:03 +0200 |
|---|---|---|
| committer | Jens Axboe <jens.axboe@oracle.com> | 2010-05-17 12:51:03 +0200 |
| commit | 69b62d01ec44fe0d505d89917392347732135a4d (patch) | |
| tree | da40561f3d87ee1073e92ca925ed3ed36708a1d7 /fs/fs-writeback.c | |
| parent | 2395e463fefd4aa8b784787e926e9b84e216d14f (diff) | |
| download | lwn-69b62d01ec44fe0d505d89917392347732135a4d.tar.gz lwn-69b62d01ec44fe0d505d89917392347732135a4d.zip | |
writeback: disable periodic old data writeback for !dirty_writeback_centisecs
Prior to 2.6.32, setting /proc/sys/vm/dirty_writeback_centisecs disabled
periodic dirty writeback from kupdate. This got broken and now causes
excessive sys CPU usage if set to zero, as we'll keep beating on
schedule().
Cc: stable@kernel.org
Reported-by: Justin Maggard <jmaggard10@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'fs/fs-writeback.c')
| -rw-r--r-- | fs/fs-writeback.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 4b37f7cea4dd..760dc8d0b4ff 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -852,6 +852,12 @@ static long wb_check_old_data_flush(struct bdi_writeback *wb) unsigned long expired; long nr_pages; + /* + * When set to zero, disable periodic writeback + */ + if (!dirty_writeback_interval) + return 0; + expired = wb->last_old_flush + msecs_to_jiffies(dirty_writeback_interval * 10); if (time_before(jiffies, expired)) @@ -947,8 +953,12 @@ int bdi_writeback_task(struct bdi_writeback *wb) break; } - wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); - schedule_timeout_interruptible(wait_jiffies); + if (dirty_writeback_interval) { + wait_jiffies = msecs_to_jiffies(dirty_writeback_interval * 10); + schedule_timeout_interruptible(wait_jiffies); + } else + schedule(); + try_to_freeze(); } |