writeback: do uninterruptible sleep in balance_dirty_pages()
Using TASK_INTERRUPTIBLE in balance_dirty_pages() seems wrong. If it's
going to do that then it must break out if signal_pending(), otherwise
it's pretty much guaranteed to degenerate into a busywait loop. Plus we
*do* want these processes to appear in D state and to contribute to load
average.
So it should be TASK_UNINTERRUPTIBLE. -- Andrew Morton
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index b840afa..b4edfe7 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -563,7 +563,7 @@
break; /* We've done our duty */
}
trace_wbc_balance_dirty_wait(&wbc, bdi);
- __set_current_state(TASK_INTERRUPTIBLE);
+ __set_current_state(TASK_UNINTERRUPTIBLE);
io_schedule_timeout(pause);
/*