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Other 2.6.34 candidate patches

PATCH In review Dave Chinner 3 participants 10 messages Jan 11, 2010 – Jan 14, 2010 XFS filesystem

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#1 lore raw

PATCH 1/3 XFS: Use list_heads for log recovery item lists

Remove the roll-your-own linked list operations.

Signed-off-by Dave Chinner <[email protected]>
---
 fs/xfs/xfs_log_recover.c |  205 ++++++++++++++++------------------------------
 fs/xfs/xfs_log_recover.h |   23 +++---
 2 files changed, 81 insertions(+), 147 deletions(-)
fs/xfs/xfs_log_recover.c +70 -135
index 69ac2e5..cd55e1c 100644
@@ -50,8 +50,6 @@
 
 STATIC int	xlog_find_zeroed(xlog_t *, xfs_daddr_t *);
 STATIC int	xlog_clear_stale_blocks(xlog_t *, xfs_lsn_t);
-STATIC void	xlog_recover_insert_item_backq(xlog_recover_item_t **q,
-					       xlog_recover_item_t *item);
 #if defined(DEBUG)
 STATIC void	xlog_recover_check_summary(xlog_t *);
 #else

@@ -1367,36 +1365,45 @@ xlog_clear_stale_blocks(
 
 STATIC xlog_recover_t *
 xlog_recover_find_tid(
-	xlog_recover_t		*q,
+	struct hlist_head	*head,
 	xlog_tid_t		tid)
 {
-	xlog_recover_t		*p = q;
+	xlog_recover_t		*trans;
+	struct hlist_node	*n;
 
-	while (p != NULL) {
-		if (p->r_log_tid == tid)
-		    break;
-		p = p->r_next;
+	hlist_for_each_entry(trans, n, head, r_list) {
+		if (trans->r_log_tid == tid)
+			return trans;
 	}
-	return p;
+	return NULL;
 }
 
 STATIC void
-xlog_recover_put_hashq(
-	xlog_recover_t		**q,
-	xlog_recover_t		*trans)
+xlog_recover_new_tid(
+	struct hlist_head	*head,
+	xlog_tid_t		tid,
+	xfs_lsn_t		lsn)
 {
-	trans->r_next = *q;
-	*q = trans;
+	xlog_recover_t		*trans;
+
+	trans = kmem_zalloc(sizeof(xlog_recover_t), KM_SLEEP);
+	trans->r_log_tid   = tid;
+	trans->r_lsn	   = lsn;
+	INIT_LIST_HEAD(&trans->r_itemq);
+
+	INIT_HLIST_NODE(&trans->r_list);
+	hlist_add_head(&trans->r_list, head);
 }
 
 STATIC void
 xlog_recover_add_item(
-	xlog_recover_item_t	**itemq)
+	struct list_head	*head)
 {
 	xlog_recover_item_t	*item;
 
 	item = kmem_zalloc(sizeof(xlog_recover_item_t), KM_SLEEP);
-	xlog_recover_insert_item_backq(itemq, item);
+	INIT_LIST_HEAD(&item->ri_list);
+	list_add_tail(&item->ri_list, head);
 }
 
 STATIC int

@@ -1409,8 +1416,7 @@ xlog_recover_add_to_cont_trans(
 	xfs_caddr_t		ptr, old_ptr;
 	int			old_len;
 
-	item = trans->r_itemq;
-	if (item == NULL) {
+	if (list_empty(&trans->r_itemq)) {
 		/* finish copying rest of trans header */
 		xlog_recover_add_item(&trans->r_itemq);
 		ptr = (xfs_caddr_t) &trans->r_theader +

@@ -1418,7 +1424,8 @@ xlog_recover_add_to_cont_trans(
 		memcpy(ptr, dp, len); /* d, s, l */
 		return 0;
 	}
-	item = item->ri_prev;
+	/* take the tail entry */
+	item = list_entry(trans->r_itemq.prev, xlog_recover_item_t, ri_list);
 
 	old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
 	old_len = item->ri_buf[item->ri_cnt-1].i_len;

@@ -1455,8 +1462,7 @@ xlog_recover_add_to_trans(
 
 	if (!len)
 		return 0;
-	item = trans->r_itemq;
-	if (item == NULL) {
+	if (list_empty(&trans->r_itemq)) {
 		/* we need to catch log corruptions here */
 		if (*(uint *)dp != XFS_TRANS_HEADER_MAGIC) {
 			xlog_warn("XFS: xlog_recover_add_to_trans: "

@@ -1474,12 +1480,15 @@ xlog_recover_add_to_trans(
 	memcpy(ptr, dp, len);
 	in_f = (xfs_inode_log_format_t *)ptr;
 
-	if (item->ri_prev->ri_total != 0 &&
-	     item->ri_prev->ri_total == item->ri_prev->ri_cnt) {
+	/* take the tail entry */
+	item = list_entry(trans->r_itemq.prev, xlog_recover_item_t, ri_list);
+	if (item->ri_total != 0 &&
+	     item->ri_total == item->ri_cnt) {
+		/* tail item is in use, get a new one */
 		xlog_recover_add_item(&trans->r_itemq);
+		item = list_entry(trans->r_itemq.prev,
+					xlog_recover_item_t, ri_list);
 	}
-	item = trans->r_itemq;
-	item = item->ri_prev;
 
 	if (item->ri_total == 0) {		/* first region to be added */
 		if (in_f->ilf_size == 0 ||

@@ -1504,96 +1513,29 @@ xlog_recover_add_to_trans(
 	return 0;
 }
 
-STATIC void
-xlog_recover_new_tid(
-	xlog_recover_t		**q,
-	xlog_tid_t		tid,
-	xfs_lsn_t		lsn)
-{
-	xlog_recover_t		*trans;
-
-	trans = kmem_zalloc(sizeof(xlog_recover_t), KM_SLEEP);
-	trans->r_log_tid   = tid;
-	trans->r_lsn	   = lsn;
-	xlog_recover_put_hashq(q, trans);
-}
-
-STATIC int
-xlog_recover_unlink_tid(
-	xlog_recover_t		**q,
-	xlog_recover_t		*trans)
-{
-	xlog_recover_t		*tp;
-	int			found = 0;
-
-	ASSERT(trans != NULL);
-	if (trans == *q) {
-		*q = (*q)->r_next;
-	} else {
-		tp = *q;
-		while (tp) {
-			if (tp->r_next == trans) {
-				found = 1;
-				break;
-			}
-			tp = tp->r_next;
-		}
-		if (!found) {
-			xlog_warn(
-			     "XFS: xlog_recover_unlink_tid: trans not found");
-			ASSERT(0);
-			return XFS_ERROR(EIO);
-		}
-		tp->r_next = tp->r_next->r_next;
-	}
-	return 0;
-}
-
-STATIC void
-xlog_recover_insert_item_backq(
-	xlog_recover_item_t	**q,
-	xlog_recover_item_t	*item)
-{
-	if (*q == NULL) {
-		item->ri_prev = item->ri_next = item;
-		*q = item;
-	} else {
-		item->ri_next		= *q;
-		item->ri_prev		= (*q)->ri_prev;
-		(*q)->ri_prev		= item;
-		item->ri_prev->ri_next	= item;
-	}
-}
-
-STATIC void
-xlog_recover_insert_item_frontq(
-	xlog_recover_item_t	**q,
-	xlog_recover_item_t	*item)
-{
-	xlog_recover_insert_item_backq(q, item);
-	*q = item;
-}
-
+/*
+ * Sort the log items in the transaction. Cancelled buffers need
+ * to be put first so they are processed before any items that might
+ * modify the buffers. If they are cancelled, then the modifications
+ * don't need to be replayed.
+ */
 STATIC int
 xlog_recover_reorder_trans(
 	xlog_recover_t		*trans)
 {
-	xlog_recover_item_t	*first_item, *itemq, *itemq_next;
-	xfs_buf_log_format_t	*buf_f;
-	ushort			flags = 0;
+	xlog_recover_item_t	*item, *n;
+	LIST_HEAD(sort_list);
+
+	list_splice_init(&trans->r_itemq, &sort_list);
+	list_for_each_entry_safe(item, n, &sort_list, ri_list) {
+		xfs_buf_log_format_t	*buf_f;
 
-	first_item = itemq = trans->r_itemq;
-	trans->r_itemq = NULL;
-	do {
-		itemq_next = itemq->ri_next;
-		buf_f = (xfs_buf_log_format_t *)itemq->ri_buf[0].i_addr;
+		buf_f = (xfs_buf_log_format_t *)item->ri_buf[0].i_addr;
 
-		switch (ITEM_TYPE(itemq)) {
+		switch (ITEM_TYPE(item)) {
 		case XFS_LI_BUF:
-			flags = buf_f->blf_flags;
-			if (!(flags & XFS_BLI_CANCEL)) {
-				xlog_recover_insert_item_frontq(&trans->r_itemq,
-								itemq);
+			if (!(buf_f->blf_flags & XFS_BLI_CANCEL)) {
+				list_move(&item->ri_list, &trans->r_itemq);
 				break;
 			}
 		case XFS_LI_INODE:

@@ -1601,7 +1543,7 @@ xlog_recover_reorder_trans(
 		case XFS_LI_QUOTAOFF:
 		case XFS_LI_EFD:
 		case XFS_LI_EFI:
-			xlog_recover_insert_item_backq(&trans->r_itemq, itemq);
+			list_move_tail(&item->ri_list, &trans->r_itemq);
 			break;
 		default:
 			xlog_warn(

@@ -1609,8 +1551,8 @@ xlog_recover_reorder_trans(
 			ASSERT(0);
 			return XFS_ERROR(EIO);
 		}
-		itemq = itemq_next;
-	} while (first_item != itemq);
+	}
+	ASSERT(list_empty(&sort_list));
 	return 0;
 }
 

@@ -2814,14 +2756,13 @@ xlog_recover_do_trans(
 	int			pass)
 {
 	int			error = 0;
-	xlog_recover_item_t	*item, *first_item;
+	xlog_recover_item_t	*item;
 
 	error = xlog_recover_reorder_trans(trans);
 	if (error)
 		return error;
 
-	first_item = item = trans->r_itemq;
-	do {
+	list_for_each_entry(item, &trans->r_itemq, ri_list) {
 		switch (ITEM_TYPE(item)) {
 		case XFS_LI_BUF:
 			error = xlog_recover_do_buffer_trans(log, item, pass);

@@ -2854,8 +2795,7 @@ xlog_recover_do_trans(
 
 		if (error)
 			return error;
-		item = item->ri_next;
-	} while (first_item != item);
+	}
 
 	return 0;
 }

@@ -2869,21 +2809,18 @@ STATIC void
 xlog_recover_free_trans(
 	xlog_recover_t		*trans)
 {
-	xlog_recover_item_t	*first_item, *item, *free_item;
+	xlog_recover_item_t	*item, *n;
 	int			i;
 
-	item = first_item = trans->r_itemq;
-	do {
-		free_item = item;
-		item = item->ri_next;
-		 /* Free the regions in the item. */
-		for (i = 0; i < free_item->ri_cnt; i++) {
-			kmem_free(free_item->ri_buf[i].i_addr);
-		}
+	list_for_each_entry_safe(item, n, &trans->r_itemq, ri_list) {
+		/* Free the regions in the item. */
+		list_del(&item->ri_list);
+		for (i = 0; i < item->ri_cnt; i++)
+			kmem_free(item->ri_buf[i].i_addr);
 		/* Free the item itself */
-		kmem_free(free_item->ri_buf);
-		kmem_free(free_item);
-	} while (first_item != item);
+		kmem_free(item->ri_buf);
+		kmem_free(item);
+	}
 	/* Free the transaction recover structure */
 	kmem_free(trans);
 }

@@ -2891,14 +2828,12 @@ xlog_recover_free_trans(
 STATIC int
 xlog_recover_commit_trans(
 	xlog_t			*log,
-	xlog_recover_t		**q,
 	xlog_recover_t		*trans,
 	int			pass)
 {
 	int			error;
 
-	if ((error = xlog_recover_unlink_tid(q, trans)))
-		return error;
+	hlist_del(&trans->r_list);
 	if ((error = xlog_recover_do_trans(log, trans, pass)))
 		return error;
 	xlog_recover_free_trans(trans);			/* no error */

@@ -2926,7 +2861,7 @@ xlog_recover_unmount_trans(
 STATIC int
 xlog_recover_process_data(
 	xlog_t			*log,
-	xlog_recover_t		*rhash[],
+	struct hlist_head	rhash[],
 	xlog_rec_header_t	*rhead,
 	xfs_caddr_t		dp,
 	int			pass)

@@ -2960,7 +2895,7 @@ xlog_recover_process_data(
 		}
 		tid = be32_to_cpu(ohead->oh_tid);
 		hash = XLOG_RHASH(tid);
-		trans = xlog_recover_find_tid(rhash[hash], tid);
+		trans = xlog_recover_find_tid(&rhash[hash], tid);
 		if (trans == NULL) {		   /* not found; add new tid */
 			if (ohead->oh_flags & XLOG_START_TRANS)
 				xlog_recover_new_tid(&rhash[hash], tid,

@@ -2978,7 +2913,7 @@ xlog_recover_process_data(
 			switch (flags) {
 			case XLOG_COMMIT_TRANS:
 				error = xlog_recover_commit_trans(log,
-						&rhash[hash], trans, pass);
+								trans, pass);
 				break;
 			case XLOG_UNMOUNT_TRANS:
 				error = xlog_recover_unmount_trans(trans);

@@ -3517,7 +3452,7 @@ xlog_do_recovery_pass(
 	int			error = 0, h_size;
 	int			bblks, split_bblks;
 	int			hblks, split_hblks, wrapped_hblks;
-	xlog_recover_t		*rhash[XLOG_RHASH_SIZE];
+	struct hlist_head	rhash[XLOG_RHASH_SIZE];
 
 	ASSERT(head_blk != tail_blk);
fs/xfs/xfs_log_recover.h +11 -12
index b225455..75d7492 100644
@@ -35,22 +35,21 @@
  * item headers are in ri_buf[0].  Additional buffers follow.
  */
 typedef struct xlog_recover_item {
-	struct xlog_recover_item *ri_next;
-	struct xlog_recover_item *ri_prev;
-	int			 ri_type;
-	int			 ri_cnt;	/* count of regions found */
-	int			 ri_total;	/* total regions */
-	xfs_log_iovec_t		 *ri_buf;	/* ptr to regions buffer */
+	struct list_head	ri_list;
+	int			ri_type;
+	int			ri_cnt;	/* count of regions found */
+	int			ri_total;	/* total regions */
+	xfs_log_iovec_t		*ri_buf;	/* ptr to regions buffer */
 } xlog_recover_item_t;
 
 struct xlog_tid;
 typedef struct xlog_recover {
-	struct xlog_recover *r_next;
-	xlog_tid_t	    r_log_tid;		/* log's transaction id */
-	xfs_trans_header_t  r_theader;		/* trans header for partial */
-	int		    r_state;		/* not needed */
-	xfs_lsn_t	    r_lsn;		/* xact lsn */
-	xlog_recover_item_t *r_itemq;		/* q for items */
+	struct hlist_node	r_list;
+	xlog_tid_t		r_log_tid;	/* log's transaction id */
+	xfs_trans_header_t	r_theader;	/* trans header for partial */
+	int			r_state;	/* not needed */
+	xfs_lsn_t		r_lsn;		/* xact lsn */
+	struct list_head	r_itemq;	/* q for items */
 } xlog_recover_t;
 
 #define ITEM_TYPE(i)	(*(ushort *)(i)->ri_buf[0].i_addr)
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author
#3 lore raw

PATCH 2/3 XFS: Don't wake the aild once per second

In reply to Dave Chinner

Now that the AIL push algorithm is traversal safe, we don't need a watchdog function in the xfsaild to catch pushes that fail to make progress. Remove the watchdog timeout and make pushes purely driven by demand. This will remove the once-per-second wakeup that is seen when the filesystem is idle and make laptop power misers happy.

Signed-off-by Dave Chinner <[email protected]>
---
 fs/xfs/linux-2.6/xfs_super.c |    7 +++----
 fs/xfs/xfs_trans_ail.c       |   19 +++++++++++--------
 2 files changed, 14 insertions(+), 12 deletions(-)
fs/xfs/linux-2.6/xfs_super.c +3 -4
index 384bd96..b1b9634 100644
@@ -877,12 +877,11 @@ xfsaild(
 {
 	struct xfs_ail	*ailp = data;
 	xfs_lsn_t	last_pushed_lsn = 0;
-	long		tout = 0;
+	long		tout = 0; /* milliseconds */
 
 	while (!kthread_should_stop()) {
-		if (tout)
-			schedule_timeout_interruptible(msecs_to_jiffies(tout));
-		tout = 1000;
+		schedule_timeout_interruptible(tout ?
+				msecs_to_jiffies(tout) : MAX_SCHEDULE_TIMEOUT);
 
 		/* swsusp */
 		try_to_freeze();
fs/xfs/xfs_trans_ail.c +11 -8
index 2ffc570..063dfbd 100644
@@ -237,14 +237,15 @@ out:
 }
 
 /*
- * Function that does the work of pushing on the AIL
+ * xfsaild_push does the work of pushing on the AIL.  Returning a timeout of
+ * zero indicates that the caller should sleep until woken.
  */
 long
 xfsaild_push(
 	struct xfs_ail	*ailp,
 	xfs_lsn_t	*last_lsn)
 {
-	long		tout = 1000; /* milliseconds */
+	long		tout = 0;
 	xfs_lsn_t	last_pushed_lsn = *last_lsn;
 	xfs_lsn_t	target =  ailp->xa_target;
 	xfs_lsn_t	lsn;

@@ -262,7 +263,7 @@ xfsaild_push(
 		 */
 		xfs_trans_ail_cursor_done(ailp, cur);
 		spin_unlock(&ailp->xa_lock);
-		last_pushed_lsn = 0;
+		*last_lsn = 0;
 		return tout;
 	}
 

@@ -279,7 +280,6 @@ xfsaild_push(
 	 * prevents use from spinning when we can't do anything or there is
 	 * lots of contention on the AIL lists.
 	 */
-	tout = 10;
 	lsn = lip->li_lsn;
 	flush_log = stuck = count = 0;
 	while ((XFS_LSN_CMP(lip->li_lsn, target) < 0)) {

@@ -376,14 +376,14 @@ xfsaild_push(
 
 	if (!count) {
 		/* We're past our target or empty, so idle */
-		tout = 1000;
+		last_pushed_lsn = 0;
 	} else if (XFS_LSN_CMP(lsn, target) >= 0) {
 		/*
 		 * We reached the target so wait a bit longer for I/O to
 		 * complete and remove pushed items from the AIL before we
 		 * start the next scan from the start of the AIL.
 		 */
-		tout += 20;
+		tout = 50;
 		last_pushed_lsn = 0;
 	} else if ((stuck * 100) / count > 90) {
 		/*

@@ -395,11 +395,14 @@ xfsaild_push(
 		 * Backoff a bit more to allow some I/O to complete before
 		 * continuing from where we were.
 		 */
-		tout += 10;
+		tout = 20;
+	} else {
+		/* more to do, but wait a short while before continuing */
+		tout = 10;
 	}
 	*last_lsn = last_pushed_lsn;
 	return tout;
-}	/* xfsaild_push */
+}
 
 
 /*
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Reviewed-by on v1 2/3
#4 lore raw

Re: [PATCH 2/3] XFS: Don't wake the aild once per second

Quoted 7 lines · Dave Chinner

Now that the AIL push algorithm is traversal safe, we don't need a watchdog function in the xfsaild to catch pushes that fail to make progress. Remove the watchdog timeout and make pushes purely driven by demand. This will remove the once-per-second wakeup that is seen when the filesystem is idle and make laptop power misers happy.

Signed-off-by Dave Chinner <[email protected]>

Looks good,

Reviewed-by Christoph Hellwig <[email protected]>

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author
#5 lore raw

PATCH 3/3 XFS: Don't wake xfsbufd when idle

In reply to Dave Chinner

The xfsbufd wakes every xfsbufd_centisecs (once per second by default) for each filesystem even when the filesystem is idle. If the xfsbufd has nothing to do, put it into a long term sleep and only wake it up when there is work pending (i.e. dirty buffers to flush soon). This will make laptop power misers happy.

Signed-off-by Dave Chinner <[email protected]>
---
 fs/xfs/linux-2.6/xfs_buf.c |   20 +++++++++++++++-----
 1 files changed, 15 insertions(+), 5 deletions(-)
fs/xfs/linux-2.6/xfs_buf.c +15 -5
index 77b8be8..b51be4e 100644
@@ -1595,6 +1595,11 @@ xfs_buf_delwri_queue(
 		list_del(&bp->b_list);
 	}
 
+	if (list_empty(dwq)) {
+		/* start xfsbufd as it is about to have something to do */
+		wake_up_process(bp->b_target->bt_task);
+	}
+
 	bp->b_flags |= _XBF_DELWRI_Q;
 	list_add_tail(&bp->b_list, dwq);
 	bp->b_queuetime = jiffies;

@@ -1644,6 +1649,8 @@ xfsbufd_wakeup(
 	list_for_each_entry(btp, &xfs_buftarg_list, bt_list) {
 		if (test_bit(XBT_FORCE_SLEEP, &btp->bt_flags))
 			continue;
+		if (list_empty(&btp->bt_delwrite_queue))
+			continue;
 		set_bit(XBT_FORCE_FLUSH, &btp->bt_flags);
 		wake_up_process(btp->bt_task);
 	}

@@ -1708,6 +1715,9 @@ xfsbufd(
 	set_freezable();
 
 	do {
+		long	age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
+		long	tout = age;
+
 		if (unlikely(freezing(current))) {
 			set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
 			refrigerator();

@@ -1715,12 +1725,12 @@ xfsbufd(
 			clear_bit(XBT_FORCE_SLEEP, &target->bt_flags);
 		}
 
-		schedule_timeout_interruptible(
-			xfs_buf_timer_centisecs * msecs_to_jiffies(10));
-
-		xfs_buf_delwri_split(target, &tmp,
-				xfs_buf_age_centisecs * msecs_to_jiffies(10));
+		/* sleep for a long time if there is nothing to do. */
+		if (list_empty(&target->bt_delwrite_queue))
+			tout = MAX_SCHEDULE_TIMEOUT;
+		schedule_timeout_interruptible(tout);
 
+		xfs_buf_delwri_split(target, &tmp, age);
 		count = 0;
 		while (!list_empty(&tmp)) {
 			bp = list_entry(tmp.next, xfs_buf_t, b_list);
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1.6.5

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Reviewed-by on v1 3/3
#6 lore raw

Re: [PATCH 3/3] XFS: Don't wake xfsbufd when idle

Quoted 7 lines · Dave Chinner

The xfsbufd wakes every xfsbufd_centisecs (once per second by default) for each filesystem even when the filesystem is idle. If the xfsbufd has nothing to do, put it into a long term sleep and only wake it up when there is work pending (i.e. dirty buffers to flush soon). This will make laptop power misers happy.

Signed-off-by Dave Chinner <[email protected]>

Looks good,

Reviewed-by Christoph Hellwig <[email protected]>

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#7 lore raw

RE: [PATCH 3/3] XFS: Don't wake xfsbufd when idle

In reply to Dave Chinner
Quoted 5 lines · Dave Chinner

The xfsbufd wakes every xfsbufd_centisecs (once per second by default) for each filesystem even when the filesystem is idle. If the xfsbufd has nothing to do, put it into a long term sleep and only wake it up when there is work pending (i.e. dirty buffers to flush soon). This will make laptop power misers happy.

Patch generally looks good but I have a question, below.

Quoted 31 lines
Signed-off-by Dave Chinner <[email protected]>
---
 fs/xfs/linux-2.6/xfs_buf.c |   20 +++++++++++++++-----
 1 files changed, 15 insertions(+), 5 deletions(-)
fs/xfs/linux-2.6/xfs_buf.c +7 -0
index 77b8be8..b51be4e 100644
@@ -1595,6 +1595,11 @@ xfs_buf_delwri_queue(
 		list_del(&bp->b_list);
 	}
 
+	if (list_empty(dwq)) {
+		/* start xfsbufd as it is about to have something to do */
+		wake_up_process(bp->b_target->bt_task);
+	}
+
 	bp->b_flags |= _XBF_DELWRI_Q;
 	list_add_tail(&bp->b_list, dwq);
 	bp->b_queuetime = jiffies;

@@ -1644,6 +1649,8 @@ xfsbufd_wakeup(
 	list_for_each_entry(btp, &xfs_buftarg_list, bt_list) {
 		if (test_bit(XBT_FORCE_SLEEP, &btp->bt_flags))
 			continue;
+		if (list_empty(&btp->bt_delwrite_queue))
+			continue;
 		set_bit(XBT_FORCE_FLUSH, &btp->bt_flags);
 		wake_up_process(btp->bt_task);
 	}

fs/xfs/linux-2.6/xfs_buf.c xfsbufd( · line 1719

Quoted 5 lines
fs/xfs/linux-2.6/xfs_buf.c +2 -0
@@ -1708,6 +1715,9 @@ xfsbufd(
 	set_freezable();
 
 	do {
+		long	age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
+		long	tout = age;

Why do you switch from using xfs_buf_timer_centisecs to using xfs_buf_age_centisecs for the timeout (in the non-empty delwrite queue case)?

fs/xfs/linux-2.6/xfs_buf.c xfsbufd( · line 1719

Quoted 10 lines
fs/xfs/linux-2.6/xfs_buf.c +1 -2
+
 		if (unlikely(freezing(current))) {
 			set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
 			refrigerator();

@@ -1715,12 +1725,12 @@ xfsbufd(
 			clear_bit(XBT_FORCE_SLEEP, &target->bt_flags);
 		}
 
-		schedule_timeout_interruptible(
-			xfs_buf_timer_centisecs * msecs_to_jiffies(10));

Here is where the timeout was computed previously.

fs/xfs/linux-2.6/xfs_buf.c xfsbufd( · line 1730

Quoted 6 lines
fs/xfs/linux-2.6/xfs_buf.c +3 -3
-
-		xfs_buf_delwri_split(target, &tmp,
-				xfs_buf_age_centisecs * msecs_to_jiffies(10));
+		/* sleep for a long time if there is nothing to do. */
+		if (list_empty(&target->bt_delwrite_queue))
+			tout = MAX_SCHEDULE_TIMEOUT;

Effect of the timout change is here...

fs/xfs/linux-2.6/xfs_buf.c xfsbufd( · line 1736

Quoted 6 lines
fs/xfs/linux-2.6/xfs_buf.c +2 -0
+		schedule_timeout_interruptible(tout);
 
+		xfs_buf_delwri_split(target, &tmp, age);
 		count = 0;
 		while (!list_empty(&tmp)) {
 			bp = list_entry(tmp.next, xfs_buf_t, b_list);

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author
#8 lore raw

PATCH v2 1/1 XFS: Don't wake xfsbufd when idle

Quoted 9 lines · Alex Elder
Quoted 5 lines · Dave Chinner

The xfsbufd wakes every xfsbufd_centisecs (once per second by default) for each filesystem even when the filesystem is idle. If the xfsbufd has nothing to do, put it into a long term sleep and only wake it up when there is work pending (i.e. dirty buffers to flush soon). This will make laptop power misers happy.

Patch generally looks good but I have a question, below.

Quoted 7 lines

Review

Quoted 3 lines
(quoted diff) +2 -0
 	do {
+		long	age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
+		long	tout = age;

Why do you switch from using xfs_buf_timer_centisecs to using xfs_buf_age_centisecs for the timeout (in the non-empty delwrite queue case)?

Because it's a bug? It should be xfs_buf_timer_centisecs here. Good catch, Alex. :)

Updated patch below

Cheers,

Dave.

Signature · 16 lines
Dave Chinner
[email protected]

XFS: Don't wake xfsbufd when idle V2

The xfsbufd wakes every xfsbufd_centisecs (once per second by
default) for each filesystem even when the filesystem is idle.
If the xfsbufd has nothing to do, put it into a long term sleep
and only wake it up when there is work pending (i.e. dirty
buffers to flush soon). This will make laptop power misers happy.

---
V2: fix xfsbufd timer interval

 fs/xfs/linux-2.6/xfs_buf.c |   20 +++++++++++++++-----
 1 files changed, 15 insertions(+), 5 deletions(-)
fs/xfs/linux-2.6/xfs_buf.c +15 -5
index 77b8be8..18ae3ba 100644
@@ -1595,6 +1595,11 @@ xfs_buf_delwri_queue(
 		list_del(&bp->b_list);
 	}
 
+	if (list_empty(dwq)) {
+		/* start xfsbufd as it is about to have something to do */
+		wake_up_process(bp->b_target->bt_task);
+	}
+
 	bp->b_flags |= _XBF_DELWRI_Q;
 	list_add_tail(&bp->b_list, dwq);
 	bp->b_queuetime = jiffies;

@@ -1644,6 +1649,8 @@ xfsbufd_wakeup(
 	list_for_each_entry(btp, &xfs_buftarg_list, bt_list) {
 		if (test_bit(XBT_FORCE_SLEEP, &btp->bt_flags))
 			continue;
+		if (list_empty(&btp->bt_delwrite_queue))
+			continue;
 		set_bit(XBT_FORCE_FLUSH, &btp->bt_flags);
 		wake_up_process(btp->bt_task);
 	}

@@ -1708,6 +1715,9 @@ xfsbufd(
 	set_freezable();
 
 	do {
+		long	age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
+		long	tout = xfs_buf_timer_centisecs * msecs_to_jiffies(10);
+
 		if (unlikely(freezing(current))) {
 			set_bit(XBT_FORCE_SLEEP, &target->bt_flags);
 			refrigerator();

@@ -1715,12 +1725,12 @@ xfsbufd(
 			clear_bit(XBT_FORCE_SLEEP, &target->bt_flags);
 		}
 
-		schedule_timeout_interruptible(
-			xfs_buf_timer_centisecs * msecs_to_jiffies(10));
-
-		xfs_buf_delwri_split(target, &tmp,
-				xfs_buf_age_centisecs * msecs_to_jiffies(10));
+		/* sleep for a long time if there is nothing to do. */
+		if (list_empty(&target->bt_delwrite_queue))
+			tout = MAX_SCHEDULE_TIMEOUT;
+		schedule_timeout_interruptible(tout);
 
+		xfs_buf_delwri_split(target, &tmp, age);
 		count = 0;
 		while (!list_empty(&tmp)) {
 			bp = list_entry(tmp.next, xfs_buf_t, b_list);

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Reviewed-by on v2 1/1
#9 lore raw

RE: [PATCH V2] XFS: Don't wake xfsbufd when idle

Quoted 18 lines · Dave Chinner
Quoted 9 lines · Alex Elder
Quoted 5 lines · Dave Chinner

The xfsbufd wakes every xfsbufd_centisecs (once per second by default) for each filesystem even when the filesystem is idle. If the xfsbufd has nothing to do, put it into a long term sleep and only wake it up when there is work pending (i.e. dirty buffers to flush soon). This will make laptop power misers happy.

Patch generally looks good but I have a question, below.

Quoted 7 lines

fs/xfs/linux-2.6/xfs_buf.c xfsbufd(

Quoted 3 lines
fs/xfs/linux-2.6/xfs_buf.c +2 -0
 	do {
+		long	age = xfs_buf_age_centisecs * msecs_to_jiffies(10);
+		long	tout = age;

Why do you switch from using xfs_buf_timer_centisecs to using xfs_buf_age_centisecs for the timeout (in the non-empty delwrite queue case)?

Quoted 8 lines

Because it's a bug? It should be xfs_buf_timer_centisecs here. Good catch, Alex. :)

Updated patch below

Cheers,

Dave.

Looks good.

Reviewed-by Alex Elder <[email protected]>

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