RE: RE: [PATCH v4 7/9] scsi: ufshpb: Add "Cold" regions timer

[Daejun Park]

Hi Avri,
> > 
> > Hi Avri,
> > 
> > > +static void ufshpb_read_to_handler(struct work_struct *work)
> > > +{
> > > +struct delayed_work *dwork = to_delayed_work(work);
> > > +struct ufshpb_lu *hpb;
> > > +struct victim_select_info *lru_info;
> > > +struct ufshpb_region *rgn;
> > > +unsigned long flags;
> > > +LIST_HEAD(expired_list);
> > > +
> > > +hpb = container_of(dwork, struct ufshpb_lu, ufshpb_read_to_work);
> > > +
> > > +if (test_and_set_bit(TIMEOUT_WORK_PENDING, 
> > >work_data_bits))
> > > +return;
> > > +
> > > +spin_lock_irqsave(>rgn_state_lock, flags);
> > > +
> > > +lru_info = >lru_info;
> > > +
> > > +list_for_each_entry(rgn, _info->lh_lru_rgn, list_lru_rgn) {
> > > +bool timedout = ktime_after(ktime_get(), 
> > > rgn->read_timeout);
> > > +
> > > +if (timedout) {
> > 
> > It is important not just to check the timeout, but how much time has passed.
> > If the time exceeded is twice the threshold, the read_timeout_expiries
> > value should be reduced by 2 instead of 1.
> Theoretically this shouldn't happened.
> Please note that POLLING_INTERVAL_MS << READ_TO_MS.
> Better add appropriate check when making those configurable.

OK, I agree.

Thanks,
Daejun

>  
> Thanks,
> Avri
> > 
> > > +rgn->read_timeout_expiries--;
> > 
> > Thanks,
> > Daejun
>  
>  
>  
>   

RE: [PATCH v4 7/9] scsi: ufshpb: Add "Cold" regions timer

[Daejun Park]

Hi Avri,

> +static void ufshpb_read_to_handler(struct work_struct *work)
> +{
> +struct delayed_work *dwork = to_delayed_work(work);
> +struct ufshpb_lu *hpb;
> +struct victim_select_info *lru_info;
> +struct ufshpb_region *rgn;
> +unsigned long flags;
> +LIST_HEAD(expired_list);
> +
> +hpb = container_of(dwork, struct ufshpb_lu, ufshpb_read_to_work);
> +
> +if (test_and_set_bit(TIMEOUT_WORK_PENDING, >work_data_bits))
> +return;
> +
> +spin_lock_irqsave(>rgn_state_lock, flags);
> +
> +lru_info = >lru_info;
> +
> +list_for_each_entry(rgn, _info->lh_lru_rgn, list_lru_rgn) {
> +bool timedout = ktime_after(ktime_get(), rgn->read_timeout);
> +
> +if (timedout) {

It is important not just to check the timeout, but how much time has passed.
If the time exceeded is twice the threshold, the read_timeout_expiries
value should be reduced by 2 instead of 1.

> +rgn->read_timeout_expiries--;

Thanks,
Daejun

RE: [PATCH v4 7/9] scsi: ufshpb: Add "Cold" regions timer

[Avri Altman]

> 
> Hi Avri,
> 
> > +static void ufshpb_read_to_handler(struct work_struct *work)
> > +{
> > +struct delayed_work *dwork = to_delayed_work(work);
> > +struct ufshpb_lu *hpb;
> > +struct victim_select_info *lru_info;
> > +struct ufshpb_region *rgn;
> > +unsigned long flags;
> > +LIST_HEAD(expired_list);
> > +
> > +hpb = container_of(dwork, struct ufshpb_lu, ufshpb_read_to_work);
> > +
> > +if (test_and_set_bit(TIMEOUT_WORK_PENDING, 
> >work_data_bits))
> > +return;
> > +
> > +spin_lock_irqsave(>rgn_state_lock, flags);
> > +
> > +lru_info = >lru_info;
> > +
> > +list_for_each_entry(rgn, _info->lh_lru_rgn, list_lru_rgn) {
> > +bool timedout = ktime_after(ktime_get(), 
> > rgn->read_timeout);
> > +
> > +if (timedout) {
> 
> It is important not just to check the timeout, but how much time has passed.
> If the time exceeded is twice the threshold, the read_timeout_expiries
> value should be reduced by 2 instead of 1.
Theoretically this shouldn't happened.
Please note that POLLING_INTERVAL_MS << READ_TO_MS.
Better add appropriate check when making those configurable.

Thanks,
Avri
> 
> > +rgn->read_timeout_expiries--;
> 
> Thanks,
> Daejun