On Sun, Sep 02, 2018 at 04:52:40PM +0800, Chao Yu wrote:
> On 2018/8/31 17:39, Sahitya Tummala wrote:
> > When dev is busy, discard thread wake up timeout can be aligned with the
> > exact time that it needs to wait for dev to come out of busy. This helps
> > to avoid unnecessary periodic wakeups and thus save some power.
> >
> > Signed-off-by: Sahitya Tummala <[email protected]>
> > ---
> > fs/f2fs/segment.c | 8 +++++++-
> > 1 file changed, 7 insertions(+), 1 deletion(-)
> >
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 8bcbb50..df14030 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -1379,6 +1379,8 @@ static int issue_discard_thread(void *data)
> > struct discard_policy dpolicy;
> > unsigned int wait_ms = DEF_MIN_DISCARD_ISSUE_TIME;
> > int issued;
> > + unsigned long interval = sbi->interval_time[REQ_TIME] * HZ;
> > + long delta;
> >
> > set_freezable();
> >
> > @@ -1410,7 +1412,11 @@ static int issue_discard_thread(void *data)
> > __wait_all_discard_cmd(sbi, &dpolicy);
> > wait_ms = dpolicy.min_interval;
> > } else if (issued == -1){
> > - wait_ms = dpolicy.mid_interval;
> > + delta = (sbi->last_time[REQ_TIME] + interval) - jiffies;
>
> I agree that we need to consider power consumption. One more consideration is
> that discard thread may need different submission frequency comparing to
> garbage
> collection thread, maybe a little fast, would it be better to split
> sbi->interval_time[REQ_TIME] according to gc/discard type.
>
> How do you think?
>
> Thanks,
>
Thanks for the review.
You mean when GC type is urgent? I see that for that case, the discard policy is
changed to DPOLICY_FORCE, which sets dpolicy->io_aware as false and hence,
cannot fall into this (issued == -1) case at all.
> > + if (delta > 0)
> > + wait_ms = jiffies_to_msecs(delta);
> > + else
> > + wait_ms = dpolicy.mid_interval;
> > } else {
> > wait_ms = dpolicy.max_interval;
> > }
> >
--
--
Sent by a consultant of the Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.
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