Re: [PATCH block/for-4.0-fixes] writeback: add missing INITIAL_JIFFIES init in global_update_bandwidth()

[Jens Axboe]

On 03/04/2015 08:30 AM, Jan Kara wrote:
> On Wed 04-03-15 10:22:43, Tejun Heo wrote:
> > 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.
>    Looks good. You can add:
> Reviewed-by: Jan Kara <jack@xxxxxxx>

We should add that it fixes c42843f2f0bbc (from 2011!) as well.

--
Jens Axboe

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