On 03/04/2015 08:37 AM, Tejun Heo wrote:
Subject: writeback: add missing INITIAL_JIFFIES init in 
global_update_bandwidth()

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 <t...@kernel.org>
Acked-by: Jan Kara <j...@suse.cz>
Cc: Wu Fengguang <fengguang...@intel.com>
Cc: Jens Axboe <ax...@kernel.dk>
Cc: sta...@vger.kernel.org
---
Added the "fixes" tag.  Jens, can you please route this one?

Yup will do, thanks Tejun.

--
Jens Axboe

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