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authorFengguang Wu <wfg@mail.ustc.edu.cn>2007-10-16 23:30:45 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-17 08:43:02 -0700
commit369f2389e7d03022abdd25e298bffb9613cd0e54 (patch)
tree1071020428c8e3eaa88642682e234de95e7a77bc /mm/page-writeback.c
parent1c0eeaf5698597146ed9b873e2f9e0961edcf0f9 (diff)
downloadlwn-369f2389e7d03022abdd25e298bffb9613cd0e54.tar.gz
lwn-369f2389e7d03022abdd25e298bffb9613cd0e54.zip
writeback: remove unnecessary wait in throttle_vm_writeout()
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> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page-writeback.c')
-rw-r--r--mm/page-writeback.c18
1 files changed, 8 insertions, 10 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index d8c21e5a1bc9..7845462064f4 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -502,16 +502,6 @@ 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);
@@ -525,6 +515,14 @@ 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;
}
}