2023-03-04 07:41:32

by Shawn Guo

[permalink] [raw]
Subject: [PATCH RESEND] cpuidle: psci: Iterate backwards over list in psci_pd_remove()

In case that psci_pd_init_topology() fails for some reason,
psci_pd_remove() will be responsible for deleting provider and removing
genpd from psci_pd_providers list. There will be a failure when removing
the cluster PD, because the cpu (child) PDs haven't been removed.

[ 0.050232] CPUidle PSCI: init PM domain cpu0
[ 0.050278] CPUidle PSCI: init PM domain cpu1
[ 0.050329] CPUidle PSCI: init PM domain cpu2
[ 0.050370] CPUidle PSCI: init PM domain cpu3
[ 0.050422] CPUidle PSCI: init PM domain cpu-cluster0
[ 0.050475] PM: genpd_remove: unable to remove cpu-cluster0
[ 0.051412] PM: genpd_remove: removed cpu3
[ 0.051449] PM: genpd_remove: removed cpu2
[ 0.051499] PM: genpd_remove: removed cpu1
[ 0.051546] PM: genpd_remove: removed cpu0

Fix the problem by iterating the provider list reversely, so that parent
PD gets removed after child's PDs like below.

[ 0.029052] CPUidle PSCI: init PM domain cpu0
[ 0.029076] CPUidle PSCI: init PM domain cpu1
[ 0.029103] CPUidle PSCI: init PM domain cpu2
[ 0.029124] CPUidle PSCI: init PM domain cpu3
[ 0.029151] CPUidle PSCI: init PM domain cpu-cluster0
[ 0.029647] PM: genpd_remove: removed cpu0
[ 0.029666] PM: genpd_remove: removed cpu1
[ 0.029690] PM: genpd_remove: removed cpu2
[ 0.029714] PM: genpd_remove: removed cpu3
[ 0.029738] PM: genpd_remove: removed cpu-cluster0

Fixes: a65a397f2451 ("cpuidle: psci: Add support for PM domains by using genpd")
Reviewed-by: Sudeep Holla <[email protected]>
Reviewed-by: Ulf Hansson <[email protected]>
Signed-off-by: Shawn Guo <[email protected]>
---
Hi Rafael,

This is a resend of the patch [1]. Could you help pick it up or let me
know if there is anything need to be improved, thanks!

Shawn

[1] https://lore.kernel.org/linux-arm-kernel/[email protected]/

drivers/cpuidle/cpuidle-psci-domain.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/cpuidle/cpuidle-psci-domain.c b/drivers/cpuidle/cpuidle-psci-domain.c
index c80cf9ddabd8..1fca250d5dec 100644
--- a/drivers/cpuidle/cpuidle-psci-domain.c
+++ b/drivers/cpuidle/cpuidle-psci-domain.c
@@ -103,7 +103,8 @@ static void psci_pd_remove(void)
struct psci_pd_provider *pd_provider, *it;
struct generic_pm_domain *genpd;

- list_for_each_entry_safe(pd_provider, it, &psci_pd_providers, link) {
+ list_for_each_entry_safe_reverse(pd_provider, it,
+ &psci_pd_providers, link) {
of_genpd_del_provider(pd_provider->node);

genpd = of_genpd_remove_last(pd_provider->node);
--
2.25.1



2023-03-07 13:10:40

by Rafael J. Wysocki

[permalink] [raw]
Subject: Re: [PATCH RESEND] cpuidle: psci: Iterate backwards over list in psci_pd_remove()

On Sat, Mar 4, 2023 at 8:41 AM Shawn Guo <[email protected]> wrote:
>
> In case that psci_pd_init_topology() fails for some reason,
> psci_pd_remove() will be responsible for deleting provider and removing
> genpd from psci_pd_providers list. There will be a failure when removing
> the cluster PD, because the cpu (child) PDs haven't been removed.
>
> [ 0.050232] CPUidle PSCI: init PM domain cpu0
> [ 0.050278] CPUidle PSCI: init PM domain cpu1
> [ 0.050329] CPUidle PSCI: init PM domain cpu2
> [ 0.050370] CPUidle PSCI: init PM domain cpu3
> [ 0.050422] CPUidle PSCI: init PM domain cpu-cluster0
> [ 0.050475] PM: genpd_remove: unable to remove cpu-cluster0
> [ 0.051412] PM: genpd_remove: removed cpu3
> [ 0.051449] PM: genpd_remove: removed cpu2
> [ 0.051499] PM: genpd_remove: removed cpu1
> [ 0.051546] PM: genpd_remove: removed cpu0
>
> Fix the problem by iterating the provider list reversely, so that parent
> PD gets removed after child's PDs like below.
>
> [ 0.029052] CPUidle PSCI: init PM domain cpu0
> [ 0.029076] CPUidle PSCI: init PM domain cpu1
> [ 0.029103] CPUidle PSCI: init PM domain cpu2
> [ 0.029124] CPUidle PSCI: init PM domain cpu3
> [ 0.029151] CPUidle PSCI: init PM domain cpu-cluster0
> [ 0.029647] PM: genpd_remove: removed cpu0
> [ 0.029666] PM: genpd_remove: removed cpu1
> [ 0.029690] PM: genpd_remove: removed cpu2
> [ 0.029714] PM: genpd_remove: removed cpu3
> [ 0.029738] PM: genpd_remove: removed cpu-cluster0
>
> Fixes: a65a397f2451 ("cpuidle: psci: Add support for PM domains by using genpd")

So I guess there should be Cc: stable for 5.10 and later?

> Reviewed-by: Sudeep Holla <[email protected]>
> Reviewed-by: Ulf Hansson <[email protected]>
> Signed-off-by: Shawn Guo <[email protected]>
> ---
> Hi Rafael,
>
> This is a resend of the patch [1]. Could you help pick it up or let me
> know if there is anything need to be improved, thanks!

Is this regarded as 6.3-rc material, or can it wait for 6.4?

2023-03-08 01:16:17

by Shawn Guo

[permalink] [raw]
Subject: Re: [PATCH RESEND] cpuidle: psci: Iterate backwards over list in psci_pd_remove()

On Tue, Mar 07, 2023 at 02:06:31PM +0100, Rafael J. Wysocki wrote:
> On Sat, Mar 4, 2023 at 8:41 AM Shawn Guo <[email protected]> wrote:
> >
> > In case that psci_pd_init_topology() fails for some reason,
> > psci_pd_remove() will be responsible for deleting provider and removing
> > genpd from psci_pd_providers list. There will be a failure when removing
> > the cluster PD, because the cpu (child) PDs haven't been removed.
> >
> > [ 0.050232] CPUidle PSCI: init PM domain cpu0
> > [ 0.050278] CPUidle PSCI: init PM domain cpu1
> > [ 0.050329] CPUidle PSCI: init PM domain cpu2
> > [ 0.050370] CPUidle PSCI: init PM domain cpu3
> > [ 0.050422] CPUidle PSCI: init PM domain cpu-cluster0
> > [ 0.050475] PM: genpd_remove: unable to remove cpu-cluster0
> > [ 0.051412] PM: genpd_remove: removed cpu3
> > [ 0.051449] PM: genpd_remove: removed cpu2
> > [ 0.051499] PM: genpd_remove: removed cpu1
> > [ 0.051546] PM: genpd_remove: removed cpu0
> >
> > Fix the problem by iterating the provider list reversely, so that parent
> > PD gets removed after child's PDs like below.
> >
> > [ 0.029052] CPUidle PSCI: init PM domain cpu0
> > [ 0.029076] CPUidle PSCI: init PM domain cpu1
> > [ 0.029103] CPUidle PSCI: init PM domain cpu2
> > [ 0.029124] CPUidle PSCI: init PM domain cpu3
> > [ 0.029151] CPUidle PSCI: init PM domain cpu-cluster0
> > [ 0.029647] PM: genpd_remove: removed cpu0
> > [ 0.029666] PM: genpd_remove: removed cpu1
> > [ 0.029690] PM: genpd_remove: removed cpu2
> > [ 0.029714] PM: genpd_remove: removed cpu3
> > [ 0.029738] PM: genpd_remove: removed cpu-cluster0
> >
> > Fixes: a65a397f2451 ("cpuidle: psci: Add support for PM domains by using genpd")
>
> So I guess there should be Cc: stable for 5.10 and later?

Yes. I was thinking that stable team will pick it up due to the Fixes
tag, but yes, explicitly copying stable would be the best.

>
> > Reviewed-by: Sudeep Holla <[email protected]>
> > Reviewed-by: Ulf Hansson <[email protected]>
> > Signed-off-by: Shawn Guo <[email protected]>
> > ---
> > Hi Rafael,
> >
> > This is a resend of the patch [1]. Could you help pick it up or let me
> > know if there is anything need to be improved, thanks!
>
> Is this regarded as 6.3-rc material, or can it wait for 6.4?

As it's regarded as a fix, it would nice to apply it for 6.3-rc.

Shawn