From 369f2389e7d03022abdd25e298bffb9613cd0e54 Mon Sep 17 00:00:00 2001 From: Fengguang Wu Date: Tue, 16 Oct 2007 23:30:45 -0700 Subject: [PATCH] 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 Cc: OGAWA Hirofumi Cc: Kumar Gala Cc: Pete Zaitcev Cc: Greg KH Reviewed-by: Rik van Riel Signed-off-by: Fengguang Wu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page-writeback.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/mm/page-writeback.c b/mm/page-writeback.c index d8c21e5..7845462 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; } } -- 1.8.2.3