| Message ID | 1430857980-1976-1-git-send-email-kamal@canonical.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/mm/page-writeback.c b/mm/page-writeback.c index 145044b..890eccc 100644 --- a/mm/page-writeback.c +++ b/mm/page-writeback.c @@ -943,7 +943,7 @@ 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
This is a note to let you know that I have just added a patch titled writeback: add missing INITIAL_JIFFIES init in global_update_bandwidth() to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue This patch is scheduled to be released in version 3.13.11-ckt20. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.13.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 78bb37186ca629cc40af030fb1b52094b153032a Mon Sep 17 00:00:00 2001 From: Tejun Heo <tj@kernel.org> Date: Wed, 4 Mar 2015 10:37:43 -0500 Subject: 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: Kamal Mostafa <kamal@canonical.com> --- mm/page-writeback.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) -- 1.9.1