xfs: reduce the number of AIL push wakeups

[cascardo/linux.git] / fs / xfs / linux-2.6 / xfs_super.c

diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c
index c45b323..c51faaa 100644 (file)
--- a/fs/xfs/linux-2.6/xfs_super.c
+++ b/fs/xfs/linux-2.6/xfs_super.c
@@ -834,8 +834,11 @@ xfsaild_wakeup(
        struct xfs_ail          *ailp,
        xfs_lsn_t               threshold_lsn)
 {
-       ailp->xa_target = threshold_lsn;
-       wake_up_process(ailp->xa_task);
+       /* only ever move the target forwards */
+       if (XFS_LSN_CMP(threshold_lsn, ailp->xa_target) > 0) {
+               ailp->xa_target = threshold_lsn;
+               wake_up_process(ailp->xa_task);
+       }
 }
 
 STATIC int
@@ -847,8 +850,17 @@ xfsaild(
        long            tout = 0; /* milliseconds */
 
        while (!kthread_should_stop()) {
-               schedule_timeout_interruptible(tout ?
-                               msecs_to_jiffies(tout) : MAX_SCHEDULE_TIMEOUT);
+               /*
+                * for short sleeps indicating congestion, don't allow us to
+                * get woken early. Otherwise all we do is bang on the AIL lock
+                * without making progress.
+                */
+               if (tout && tout <= 20)
+                       __set_current_state(TASK_KILLABLE);
+               else
+                       __set_current_state(TASK_INTERRUPTIBLE);
+               schedule_timeout(tout ?
+                                msecs_to_jiffies(tout) : MAX_SCHEDULE_TIMEOUT);
 
                /* swsusp */
                try_to_freeze();