Commit 0b335b9d authored by Artem Bityutskiy's avatar Artem Bityutskiy
Browse files

UBIFS: slightly optimize write-buffer timer usage 



This patch adds the following minor optimization:

1. If write-buffer does not use the timer, indicate it with the
   wbuf->no_timer variable, instead of using the wbuf->softlimit
   variable. This is better because wbuf->softlimit is of ktime_t
   type, and the ktime_to_ns function contains 64-bit multiplication.

2. Do not call the 'hrtimer_cancel()' function for write-buffers
   which do not use timers.

3. Do not cancel the timer in 'ubifs_put_super()' because the
   synchronization function does this.

This patch also removes a confusing comment.

Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 70aee2f1

fs/ubifs/io.c

+3 −6
Original line number Diff line number Diff line
@@ -312,7 +312,7 @@ static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf) 
{

	ubifs_assert(!hrtimer_active(&wbuf->timer));



	if (!ktime_to_ns(wbuf->softlimit))

	if (wbuf->no_timer)

		return;

	dbg_io("set timer for jhead %d, %llu-%llu millisecs", wbuf->jhead,

	       ktime_to_ns(wbuf->softlimit)/USEC_PER_SEC,
@@ -327,11 +327,8 @@ static void new_wbuf_timer_nolock(struct ubifs_wbuf *wbuf) 
 */

static void cancel_wbuf_timer_nolock(struct ubifs_wbuf *wbuf)

{

	/*

	 * If the syncer is waiting for the lock (from the background thread's

	 * context) and another task is changing write-buffer then the syncing

	 * should be canceled.

	 */

	if (wbuf->no_timer)

		return;

	wbuf->need_sync = 0;

	hrtimer_cancel(&wbuf->timer);

}

fs/ubifs/super.c

+2 −4
Original line number Diff line number Diff line
@@ -797,7 +797,7 @@ static int alloc_wbufs(struct ubifs_info *c) 
	 * does not need to be synchronized by timer.

	 */

	c->jheads[GCHD].wbuf.dtype = UBI_LONGTERM;

	c->jheads[GCHD].wbuf.softlimit = ktime_set(0, 0);

	c->jheads[GCHD].wbuf.no_timer = 1;



	return 0;

}
@@ -1754,10 +1754,8 @@ static void ubifs_put_super(struct super_block *sb) 


		/* Synchronize write-buffers */

		if (c->jheads)

			for (i = 0; i < c->jhead_cnt; i++) {

			for (i = 0; i < c->jhead_cnt; i++)

				ubifs_wbuf_sync(&c->jheads[i].wbuf);

				hrtimer_cancel(&c->jheads[i].wbuf.timer);

			}



		/*

		 * On fatal errors c->ro_media is set to 1, in which case we do

fs/ubifs/ubifs.h

+4 −2
Original line number Diff line number Diff line
@@ -654,7 +654,8 @@ typedef int (*ubifs_lpt_scan_callback)(struct ubifs_info *c, 
 * @delta: hard and soft timeouts delta (the timer expire inteval is @softlimit

 *         and @softlimit + @delta)

 * @timer: write-buffer timer

 * @need_sync: it is set if its timer expired and needs sync

 * @no_timer: non-zero if this write-buffer does not timer

 * @need_sync: non-zero if its timer expired and needs sync

 * @next_ino: points to the next position of the following inode number

 * @inodes: stores the inode numbers of the nodes which are in wbuf

 *
@@ -683,7 +684,8 @@ struct ubifs_wbuf { 
	ktime_t softlimit;

	unsigned long long delta;

	struct hrtimer timer;

	int need_sync;

	unsigned int no_timer:1;

	unsigned int need_sync:1;

	int next_ino;

	ino_t *inodes;

};

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