[v2] psi: Fix avg trigger being fired unexpectedly.

[PATCH v2] psi: Fix avg trigger being fired unexpectedly.

Posted by Levi Yun 1 year, 11 months ago

commit 915a087e4c473("psi: Fix trigger being fired unexpectedly at initial")
fixes unexpected event fired when group->total accumulated for PSI_POLL.
But, for PSI_AVGS, win->value should be initialized with group->total[PSI_AVGS].
Moreover, to get exact initial value for win->value, it should be set
under each trigger lock to avoid concurrent changes to group->total[].

Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
Acked-by: Suren Baghdasaryan <surenb@google.com>
---
v2: Fix commit message.
---
 kernel/sched/psi.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
index 7b4aa5809c0f..e7f66ab2ad3e 100644
--- a/kernel/sched/psi.c
+++ b/kernel/sched/psi.c
@@ -1323,9 +1323,6 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
 	t->state = state;
 	t->threshold = threshold_us * NSEC_PER_USEC;
 	t->win.size = window_us * NSEC_PER_USEC;
-	window_reset(&t->win, sched_clock(),
-			group->total[PSI_POLL][t->state], 0);
-
 	t->event = 0;
 	t->last_event_time = 0;
 	t->of = of;
@@ -1336,6 +1333,8 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,

 	if (privileged) {
 		mutex_lock(&group->rtpoll_trigger_lock);
+		window_reset(&t->win, sched_clock(),
+				group->total[PSI_POLL][t->state], 0);

 		if (!rcu_access_pointer(group->rtpoll_task)) {
 			struct task_struct *task;
@@ -1361,6 +1360,9 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
 	} else {
 		mutex_lock(&group->avgs_lock);

+		window_reset(&t->win, sched_clock(),
+				group->total[PSI_AVGS][t->state], 0);
+
 		list_add(&t->node, &group->avg_triggers);
 		group->avg_nr_triggers[t->state]++;

--
2.39.2

Re: [PATCH v2] psi: Fix avg trigger being fired unexpectedly.

Posted by Markus Elfring 1 year, 9 months ago

…
> But, for PSI_AVGS, win->value should be initialized with group->total[PSI_AVGS].
> Moreover, to get exact initial value for win->value, it should be set
> under each trigger lock to avoid concurrent changes to group->total[].
…
>  kernel/sched/psi.c | 8 +++++---
…

* Can imperative wordings be desirable for such a change description?

* Is there a need to perform proposed adjustments as separate update steps?
  https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.9-rc6#n81

* Would you like to add the tag “Fixes” accordingly?


Regards,
Markus

Re: [PATCH v2] psi: Fix avg trigger being fired unexpectedly.

Posted by levi.yun 1 year, 11 months ago

Gentle ping..

On Mon, Feb 26, 2024 at 09:12:37PM +0000, Levi Yun wrote:
> commit 915a087e4c473("psi: Fix trigger being fired unexpectedly at initial")
> fixes unexpected event fired when group->total accumulated for PSI_POLL.
> But, for PSI_AVGS, win->value should be initialized with group->total[PSI_AVGS].
> Moreover, to get exact initial value for win->value, it should be set
> under each trigger lock to avoid concurrent changes to group->total[].
>
> Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
> Acked-by: Suren Baghdasaryan <surenb@google.com>
> ---
> v2: Fix commit message.
> ---
>  kernel/sched/psi.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> index 7b4aa5809c0f..e7f66ab2ad3e 100644
> --- a/kernel/sched/psi.c
> +++ b/kernel/sched/psi.c
> @@ -1323,9 +1323,6 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
>  	t->state = state;
>  	t->threshold = threshold_us * NSEC_PER_USEC;
>  	t->win.size = window_us * NSEC_PER_USEC;
> -	window_reset(&t->win, sched_clock(),
> -			group->total[PSI_POLL][t->state], 0);
> -
>  	t->event = 0;
>  	t->last_event_time = 0;
>  	t->of = of;
> @@ -1336,6 +1333,8 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
>
>  	if (privileged) {
>  		mutex_lock(&group->rtpoll_trigger_lock);
> +		window_reset(&t->win, sched_clock(),
> +				group->total[PSI_POLL][t->state], 0);
>
>  		if (!rcu_access_pointer(group->rtpoll_task)) {
>  			struct task_struct *task;
> @@ -1361,6 +1360,9 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
>  	} else {
>  		mutex_lock(&group->avgs_lock);
>
> +		window_reset(&t->win, sched_clock(),
> +				group->total[PSI_AVGS][t->state], 0);
> +
>  		list_add(&t->node, &group->avg_triggers);
>  		group->avg_nr_triggers[t->state]++;
>
> --
> 2.39.2

Re: [PATCH v2] psi: Fix avg trigger being fired unexpectedly.

Posted by Suren Baghdasaryan 1 year, 10 months ago

On Tue, Mar 12, 2024 at 6:10 AM levi.yun <ppbuk5246@gmail.com> wrote:
>
> Gentle ping..
>
> On Mon, Feb 26, 2024 at 09:12:37PM +0000, Levi Yun wrote:
> > commit 915a087e4c473("psi: Fix trigger being fired unexpectedly at initial")
> > fixes unexpected event fired when group->total accumulated for PSI_POLL.
> > But, for PSI_AVGS, win->value should be initialized with group->total[PSI_AVGS].
> > Moreover, to get exact initial value for win->value, it should be set
> > under each trigger lock to avoid concurrent changes to group->total[].
> >
> > Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
> > Acked-by: Suren Baghdasaryan <surenb@google.com>

Hi Peter,
Could you please pull this patch into your tree? I don't see it in any
tree, so I think you missed it.
Thanks,
Suren.

> > ---
> > v2: Fix commit message.
> > ---
> >  kernel/sched/psi.c | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> >
> > diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> > index 7b4aa5809c0f..e7f66ab2ad3e 100644
> > --- a/kernel/sched/psi.c
> > +++ b/kernel/sched/psi.c
> > @@ -1323,9 +1323,6 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
> >       t->state = state;
> >       t->threshold = threshold_us * NSEC_PER_USEC;
> >       t->win.size = window_us * NSEC_PER_USEC;
> > -     window_reset(&t->win, sched_clock(),
> > -                     group->total[PSI_POLL][t->state], 0);
> > -
> >       t->event = 0;
> >       t->last_event_time = 0;
> >       t->of = of;
> > @@ -1336,6 +1333,8 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
> >
> >       if (privileged) {
> >               mutex_lock(&group->rtpoll_trigger_lock);
> > +             window_reset(&t->win, sched_clock(),
> > +                             group->total[PSI_POLL][t->state], 0);
> >
> >               if (!rcu_access_pointer(group->rtpoll_task)) {
> >                       struct task_struct *task;
> > @@ -1361,6 +1360,9 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
> >       } else {
> >               mutex_lock(&group->avgs_lock);
> >
> > +             window_reset(&t->win, sched_clock(),
> > +                             group->total[PSI_AVGS][t->state], 0);
> > +
> >               list_add(&t->node, &group->avg_triggers);
> >               group->avg_nr_triggers[t->state]++;
> >
> > --
> > 2.39.2

Re: [PATCH v2] psi: Fix avg trigger being fired unexpectedly.

Posted by Suren Baghdasaryan 1 year, 9 months ago

On Tue, Mar 26, 2024 at 10:49 AM Suren Baghdasaryan <surenb@google.com> wrote:
>
> On Tue, Mar 12, 2024 at 6:10 AM levi.yun <ppbuk5246@gmail.com> wrote:
> >
> > Gentle ping..
> >
> > On Mon, Feb 26, 2024 at 09:12:37PM +0000, Levi Yun wrote:
> > > commit 915a087e4c473("psi: Fix trigger being fired unexpectedly at initial")
> > > fixes unexpected event fired when group->total accumulated for PSI_POLL.
> > > But, for PSI_AVGS, win->value should be initialized with group->total[PSI_AVGS].
> > > Moreover, to get exact initial value for win->value, it should be set
> > > under each trigger lock to avoid concurrent changes to group->total[].
> > >
> > > Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
> > > Acked-by: Suren Baghdasaryan <surenb@google.com>
>
> Hi Peter,
> Could you please pull this patch into your tree? I don't see it in any
> tree, so I think you missed it.

I heard Peter is currently unavailable. Ingo, would you please take
this patch into the scheduler tree?
Thanks,
Suren.

> Thanks,
> Suren.
>
> > > ---
> > > v2: Fix commit message.
> > > ---
> > >  kernel/sched/psi.c | 8 +++++---
> > >  1 file changed, 5 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> > > index 7b4aa5809c0f..e7f66ab2ad3e 100644
> > > --- a/kernel/sched/psi.c
> > > +++ b/kernel/sched/psi.c
> > > @@ -1323,9 +1323,6 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
> > >       t->state = state;
> > >       t->threshold = threshold_us * NSEC_PER_USEC;
> > >       t->win.size = window_us * NSEC_PER_USEC;
> > > -     window_reset(&t->win, sched_clock(),
> > > -                     group->total[PSI_POLL][t->state], 0);
> > > -
> > >       t->event = 0;
> > >       t->last_event_time = 0;
> > >       t->of = of;
> > > @@ -1336,6 +1333,8 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
> > >
> > >       if (privileged) {
> > >               mutex_lock(&group->rtpoll_trigger_lock);
> > > +             window_reset(&t->win, sched_clock(),
> > > +                             group->total[PSI_POLL][t->state], 0);
> > >
> > >               if (!rcu_access_pointer(group->rtpoll_task)) {
> > >                       struct task_struct *task;
> > > @@ -1361,6 +1360,9 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
> > >       } else {
> > >               mutex_lock(&group->avgs_lock);
> > >
> > > +             window_reset(&t->win, sched_clock(),
> > > +                             group->total[PSI_AVGS][t->state], 0);
> > > +
> > >               list_add(&t->node, &group->avg_triggers);
> > >               group->avg_nr_triggers[t->state]++;
> > >
> > > --
> > > 2.39.2

Re: [PATCH v2] psi: Fix avg trigger being fired unexpectedly.

Posted by Suren Baghdasaryan 1 year, 10 months ago

On Tue, Mar 26, 2024 at 10:49 AM Suren Baghdasaryan <surenb@google.com> wrote:
>
> On Tue, Mar 12, 2024 at 6:10 AM levi.yun <ppbuk5246@gmail.com> wrote:
> >
> > Gentle ping..
> >
> > On Mon, Feb 26, 2024 at 09:12:37PM +0000, Levi Yun wrote:
> > > commit 915a087e4c473("psi: Fix trigger being fired unexpectedly at initial")
> > > fixes unexpected event fired when group->total accumulated for PSI_POLL.
> > > But, for PSI_AVGS, win->value should be initialized with group->total[PSI_AVGS].
> > > Moreover, to get exact initial value for win->value, it should be set
> > > under each trigger lock to avoid concurrent changes to group->total[].
> > >
> > > Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
> > > Acked-by: Suren Baghdasaryan <surenb@google.com>
>
> Hi Peter,
> Could you please pull this patch into your tree? I don't see it in any
> tree, so I think you missed it.

Forgot to set the right recipient. Fixed now.


> Thanks,
> Suren.
>
> > > ---
> > > v2: Fix commit message.
> > > ---
> > >  kernel/sched/psi.c | 8 +++++---
> > >  1 file changed, 5 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/kernel/sched/psi.c b/kernel/sched/psi.c
> > > index 7b4aa5809c0f..e7f66ab2ad3e 100644
> > > --- a/kernel/sched/psi.c
> > > +++ b/kernel/sched/psi.c
> > > @@ -1323,9 +1323,6 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
> > >       t->state = state;
> > >       t->threshold = threshold_us * NSEC_PER_USEC;
> > >       t->win.size = window_us * NSEC_PER_USEC;
> > > -     window_reset(&t->win, sched_clock(),
> > > -                     group->total[PSI_POLL][t->state], 0);
> > > -
> > >       t->event = 0;
> > >       t->last_event_time = 0;
> > >       t->of = of;
> > > @@ -1336,6 +1333,8 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
> > >
> > >       if (privileged) {
> > >               mutex_lock(&group->rtpoll_trigger_lock);
> > > +             window_reset(&t->win, sched_clock(),
> > > +                             group->total[PSI_POLL][t->state], 0);
> > >
> > >               if (!rcu_access_pointer(group->rtpoll_task)) {
> > >                       struct task_struct *task;
> > > @@ -1361,6 +1360,9 @@ struct psi_trigger *psi_trigger_create(struct psi_group *group, char *buf,
> > >       } else {
> > >               mutex_lock(&group->avgs_lock);
> > >
> > > +             window_reset(&t->win, sched_clock(),
> > > +                             group->total[PSI_AVGS][t->state], 0);
> > > +
> > >               list_add(&t->node, &group->avg_triggers);
> > >               group->avg_nr_triggers[t->state]++;
> > >
> > > --
> > > 2.39.2