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authorTejun Heo <tj@kernel.org>2015-03-04 10:37:43 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-04-19 10:10:47 +0200
commitf16678367dae3cd3da3fd0c93b13bad7ad8d301b (patch)
tree8f590d4701e9e1ef193938cd356fd9fb83779f30 /mm
parentdfb06c85571e687aee393dfb72222e3eeec24813 (diff)
downloadlinux-linaro-stable-f16678367dae3cd3da3fd0c93b13bad7ad8d301b.tar.gz
writeback: add missing INITIAL_JIFFIES init in global_update_bandwidth()
commit 7d70e15480c0450d2bfafaad338a32e884fc215e upstream. global_update_bandwidth() uses static variable update_time as the timestamp for the last update but forgets to initialize it to INITIALIZE_JIFFIES. This means that global_dirty_limit will be 5 mins into the future on 32bit and some large amount jiffies into the past on 64bit. This isn't critical as the only effect is that global_dirty_limit won't be updated for the first 5 mins after booting on 32bit machines, especially given the auxiliary nature of global_dirty_limit's role - protecting against global dirty threshold's sudden dips; however, it does lead to unintended suboptimal behavior. Fix it. Fixes: c42843f2f0bb ("writeback: introduce smoothed global dirty limit") Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Jan Kara <jack@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Jens Axboe <axboe@fb.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/page-writeback.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 73cbc5dc150b..d42a8a83aaf1 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -858,7 +858,7 @@ static void global_update_bandwidth(unsigned long thresh,
unsigned long now)
{
static DEFINE_SPINLOCK(dirty_lock);
- static unsigned long update_time;
+ static unsigned long update_time = INITIAL_JIFFIES;
/*
* check locklessly first to optimize away locking for the most time