2022-04-01 15:29:05

by Hailong Liu

Subject: [PATCH] psi: Fix trigger being fired unexpectedly at initial

When a trigger being created, its win.start_value and win.start_time are
reset to zero. If group->total[PSI_POLL][t->state] has accumulated before,
this trigger will be fired unexpectedly in the next period, even if its
growth time does not reach its threshold.

So set the window of the new trigger to the current state value.

Signed-off-by: Hailong Liu <[email protected]>
---
kernel/sched/psi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index a4fa3aadfcba..5a49a8c8783e 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1117,7 +1117,8 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group,
t->state = state;
t->threshold = threshold_us * NSEC_PER_USEC;
t->win.size = window_us * NSEC_PER_USEC;
- window_reset(&t->win, 0, 0, 0);
+ window_reset(&t->win, sched_clock(),
+ group->total[PSI_POLL][t->state], 0);

t->event = 0;
t->last_event_time = 0;
--
2.19.1.6.gb485710b

2022-04-02 09:24:26

by Suren Baghdasaryan

Subject: Re: [PATCH] psi: Fix trigger being fired unexpectedly at initial

On Thu, Mar 31, 2022 at 10:10 PM Hailong Liu
<[email protected]> wrote:
>
> When a trigger being created, its win.start_value and win.start_time are
> reset to zero. If group->total[PSI_POLL][t->state] has accumulated before,
> this trigger will be fired unexpectedly in the next period, even if its
> growth time does not reach its threshold.
>
> So set the window of the new trigger to the current state value.

Makes sense to me. Thanks!

>
> Signed-off-by: Hailong Liu <[email protected]>

Acked-by: Suren Baghdasaryan <[email protected]>

> ---
> kernel/sched/psi.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> index a4fa3aadfcba..5a49a8c8783e 100644
> --- a/kernel/sched/psi.c
> +++ b/kernel/sched/psi.c
> @@ -1117,7 +1117,8 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group,
> t->state = state;
> t->threshold = threshold_us * NSEC_PER_USEC;
> t->win.size = window_us * NSEC_PER_USEC;
> - window_reset(&t->win, 0, 0, 0);
> + window_reset(&t->win, sched_clock(),
> + group->total[PSI_POLL][t->state], 0);
>
> t->event = 0;
> t->last_event_time = 0;
> --
> 2.19.1.6.gb485710b
>

2022-04-06 16:06:36

by Peter Zijlstra

Subject: Re: [PATCH] psi: Fix trigger being fired unexpectedly at initial

On Fri, Apr 01, 2022 at 09:19:17AM -0700, Suren Baghdasaryan wrote:
> On Thu, Mar 31, 2022 at 10:10 PM Hailong Liu
> <[email protected]> wrote:
> >
> > When a trigger being created, its win.start_value and win.start_time are
> > reset to zero. If group->total[PSI_POLL][t->state] has accumulated before,
> > this trigger will be fired unexpectedly in the next period, even if its
> > growth time does not reach its threshold.
> >
> > So set the window of the new trigger to the current state value.
>
> Makes sense to me. Thanks!
>
> >
> > Signed-off-by: Hailong Liu <[email protected]>
>
> Acked-by: Suren Baghdasaryan <[email protected]>

Thanks!

2022-04-22 18:53:19

by tip-bot2 for Borislav Petkov (AMD)

Subject: [tip: sched/core] psi: Fix trigger being fired unexpectedly at initial

The following commit has been merged into the sched/core branch of tip:

Commit-ID: 915a087e4c47334a2f7ba2a4092c4bade0873769
Gitweb: https://git.kernel.org/tip/915a087e4c47334a2f7ba2a4092c4bade0873769
Author: Hailong Liu <[email protected]>
AuthorDate: Fri, 01 Apr 2022 13:10:11 +08:00
Committer: Peter Zijlstra <[email protected]>
CommitterDate: Fri, 22 Apr 2022 12:14:06 +02:00

psi: Fix trigger being fired unexpectedly at initial

When a trigger being created, its win.start_value and win.start_time are
reset to zero. If group->total[PSI_POLL][t->state] has accumulated before,
this trigger will be fired unexpectedly in the next period, even if its
growth time does not reach its threshold.

So set the window of the new trigger to the current state value.

Signed-off-by: Hailong Liu <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Suren Baghdasaryan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
---
kernel/sched/psi.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index a4fa3aa..5a49a8c 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1117,7 +1117,8 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group,
t->state = state;
t->threshold = threshold_us * NSEC_PER_USEC;
t->win.size = window_us * NSEC_PER_USEC;
- window_reset(&t->win, 0, 0, 0);
+ window_reset(&t->win, sched_clock(),
+ group->total[PSI_POLL][t->state], 0);

t->event = 0;
t->last_event_time = 0;