We don't want to introduce pointless delays in throttle_vm_writeout()
when the writeback limits are not yet exceeded, do we?
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn>
---
mm/page-writeback.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)
--- linux-2.6.23-rc8-mm1.orig/mm/page-writeback.c
+++ linux-2.6.23-rc8-mm1/mm/page-writeback.c
@@ -507,16 +507,6 @@ void throttle_vm_writeout(gfp_t gfp_mask
long background_thresh;
long dirty_thresh;
- if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO)) {
- /*
- * The caller might hold locks which can prevent IO completion
- * or progress in the filesystem. So we cannot just sit here
- * waiting for IO to complete.
- */
- congestion_wait(WRITE, HZ/10);
- return;
- }
-
for ( ; ; ) {
get_dirty_limits(&background_thresh, &dirty_thresh, NULL, NULL);
@@ -530,6 +520,14 @@ void throttle_vm_writeout(gfp_t gfp_mask
global_page_state(NR_WRITEBACK) <= dirty_thresh)
break;
congestion_wait(WRITE, HZ/10);
+
+ /*
+ * The caller might hold locks which can prevent IO completion
+ * or progress in the filesystem. So we cannot just sit here
+ * waiting for IO to complete.
+ */
+ if ((gfp_mask & (__GFP_FS|__GFP_IO)) != (__GFP_FS|__GFP_IO))
+ break;
}
}
-
