The patch titled
mm: clean up clearing of BDI_pending bit in bdi_forker_thread()
has been added to the -mm tree. Its filename is
mm-clean-up-clearing-of-bdi_pending-bit-in-bdi_forker_thread.patch
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------------------------------------------------------
Subject: mm: clean up clearing of BDI_pending bit in bdi_forker_thread()
From: Jan Kara <jack@xxxxxxx>
bdi_forker_thread() clears BDI_pending bit at the end of the main loop.
However clearing of this bit must not be done in some cases which is
handled by calling 'continue' from switch statement. That's kind of
unusual construct and without a good reason so change the function into
more intuitive code flow.
Signed-off-by: Jan Kara <jack@xxxxxxx>
Acked-by: Wu Fengguang <fengguang.wu@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/backing-dev.c | 23 ++++++++++++++---------
1 file changed, 14 insertions(+), 9 deletions(-)
diff -puN mm/backing-dev.c~mm-clean-up-clearing-of-bdi_pending-bit-in-bdi_forker_thread mm/backing-dev.c
--- a/mm/backing-dev.c~mm-clean-up-clearing-of-bdi_pending-bit-in-bdi_forker_thread
+++ a/mm/backing-dev.c
@@ -359,6 +359,17 @@ static unsigned long bdi_longest_inactiv
return max(5UL * 60 * HZ, interval);
}
+/*
+ * Clear pending bit and wakeup anybody waiting for flusher thread creation or
+ * shutdown
+ */
+static void bdi_clear_pending(struct backing_dev_info *bdi)
+{
+ clear_bit(BDI_pending, &bdi->state);
+ smp_mb__after_clear_bit();
+ wake_up_bit(&bdi->state, BDI_pending);
+}
+
static int bdi_forker_thread(void *ptr)
{
struct bdi_writeback *me = ptr;
@@ -469,11 +480,13 @@ static int bdi_forker_thread(void *ptr)
spin_unlock_bh(&bdi->wb_lock);
wake_up_process(task);
}
+ bdi_clear_pending(bdi);
break;
case KILL_THREAD:
__set_current_state(TASK_RUNNING);
kthread_stop(task);
+ bdi_clear_pending(bdi);
break;
case NO_ACTION:
@@ -489,16 +502,8 @@ static int bdi_forker_thread(void *ptr)
else
schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10));
try_to_freeze();
- /* Back to the main loop */
- continue;
+ break;
}
-
- /*
- * Clear pending bit and wakeup anybody waiting to tear us down.
- */
- clear_bit(BDI_pending, &bdi->state);
- smp_mb__after_clear_bit();
- wake_up_bit(&bdi->state, BDI_pending);
}
return 0;
_
Patches currently in -mm which might be from jack@xxxxxxx are
linux-next.patch
mm-vmscan-do-not-writeback-filesystem-pages-in-direct-reclaim.patch
mm-vmscan-remove-dead-code-related-to-lumpy-reclaim-waiting-on-pages-under-writeback.patch
xfs-warn-if-direct-reclaim-tries-to-writeback-pages.patch
ext4-warn-if-direct-reclaim-tries-to-writeback-pages.patch
mm-vmscan-do-not-writeback-filesystem-pages-in-kswapd-except-in-high-priority.patch
mm-vmscan-throttle-reclaim-if-encountering-too-many-dirty-pages-under-writeback.patch
mm-vmscan-immediately-reclaim-end-of-lru-dirty-pages-when-writeback-completes.patch
mm-clean-up-clearing-of-bdi_pending-bit-in-bdi_forker_thread.patch
mm-add-comment-explaining-task-state-setting-in-bdi_forker_thread.patch
mm-add-comment-explaining-task-state-setting-in-bdi_forker_thread-fix.patch
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