| Message ID | 20191205103330.27166-1-ulf.hansson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | cpuidle: psci: Support CPU hotplug for the hierarchical model | expand |
On Thu, Dec 05, 2019 at 11:33:30AM +0100, Ulf Hansson wrote: > When the hierarchical CPU topology is used and when a CPU is put offline, > that CPU prevents its PM domain from being powered off, which is because > genpd observes the corresponding attached device as being active from a > runtime PM point of view. Furthermore, any potential master PM domains are > also prevented from being powered off. > > To address this limitation, let's add add a new CPU hotplug state > (CPUHP_AP_CPU_PM_STARTING) and register up/down callbacks for it, which > allows us to deal with runtime PM accordingly. > > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> > --- > > Lorenzo, Sudeep, Rafael, Daniel, > > Note that, this patch is based upon a recently posted series [1] and the intent > is to queue it on top. I can fold it into the series and resend it all, if that > makes it easier for people. Just tell me what you prefer. > > Kind regards > Uffe > > [1] > https://patchwork.kernel.org/cover/11263735/ > > --- > drivers/cpuidle/cpuidle-psci.c | 45 +++++++++++++++++++++++++++++++++- > include/linux/cpuhotplug.h | 1 + > 2 files changed, 45 insertions(+), 1 deletion(-) > > diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c > index 835c7c3aa118..46b481c524cc 100644 > --- a/drivers/cpuidle/cpuidle-psci.c > +++ b/drivers/cpuidle/cpuidle-psci.c > @@ -8,6 +8,7 @@ > > #define pr_fmt(fmt) "CPUidle PSCI: " fmt > > +#include <linux/cpuhotplug.h> > #include <linux/cpuidle.h> > #include <linux/cpumask.h> > #include <linux/cpu_pm.h> > @@ -31,6 +32,7 @@ struct psci_cpuidle_data { > > static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data); > static DEFINE_PER_CPU(u32, domain_state); > +static bool psci_cpuidle_use_cpuhp; > > void psci_set_domain_state(u32 state) > { > @@ -72,6 +74,44 @@ static int psci_enter_domain_idle_state(struct cpuidle_device *dev, > return ret; > } > > +static int psci_idle_cpuhp_up(unsigned int cpu) > +{ > + struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); > + > + if (pd_dev) > + pm_runtime_get_sync(pd_dev); > + > + return 0; > +} > + > +static int psci_idle_cpuhp_down(unsigned int cpu) > +{ > + struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); > + > + if (pd_dev) { > + pm_runtime_put_sync(pd_dev); > + /* Clear domain state to start fresh at next online. */ > + psci_set_domain_state(0); > + } > + > + return 0; > +} > + > +static void psci_idle_init_cpuhp(void) > +{ > + int err; > + > + if (!psci_cpuidle_use_cpuhp) > + return; > + > + err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING, > + "cpuidle/psci:online", > + psci_idle_cpuhp_up, > + psci_idle_cpuhp_down); I would make it a cpuhp_setup_state() call and remove if (cpu_online(cpu)) pm_runtime_get_sync_dev(dev); in check in psci_dt_attach_cpu(). Lorenzo > + if (err) > + pr_warn("Failed %d while setup cpuhp state\n", err); > +} > + > static int psci_enter_idle_state(struct cpuidle_device *dev, > struct cpuidle_driver *drv, int idx) > { > @@ -161,9 +201,11 @@ static int __init psci_dt_cpu_init_idle(struct cpuidle_driver *drv, > } > > /* Manage the deepest state via a dedicated enter-function. */ > - if (dev) > + if (dev) { > drv->states[state_count - 1].enter = > psci_enter_domain_idle_state; > + psci_cpuidle_use_cpuhp = true; > + } > > data->dev = dev; > > @@ -285,6 +327,7 @@ static int __init psci_idle_init(void) > goto out_fail; > } > > + psci_idle_init_cpuhp(); > return 0; > > out_fail: > diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h > index e51ee772b9f5..01f04ed6ad92 100644 > --- a/include/linux/cpuhotplug.h > +++ b/include/linux/cpuhotplug.h > @@ -95,6 +95,7 @@ enum cpuhp_state { > CPUHP_AP_OFFLINE, > CPUHP_AP_SCHED_STARTING, > CPUHP_AP_RCUTREE_DYING, > + CPUHP_AP_CPU_PM_STARTING, > CPUHP_AP_IRQ_GIC_STARTING, > CPUHP_AP_IRQ_HIP04_STARTING, > CPUHP_AP_IRQ_ARMADA_XP_STARTING, > -- > 2.17.1 >
On Thu, 5 Dec 2019 at 19:07, Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> wrote: > > On Thu, Dec 05, 2019 at 11:33:30AM +0100, Ulf Hansson wrote: > > When the hierarchical CPU topology is used and when a CPU is put offline, > > that CPU prevents its PM domain from being powered off, which is because > > genpd observes the corresponding attached device as being active from a > > runtime PM point of view. Furthermore, any potential master PM domains are > > also prevented from being powered off. > > > > To address this limitation, let's add add a new CPU hotplug state > > (CPUHP_AP_CPU_PM_STARTING) and register up/down callbacks for it, which > > allows us to deal with runtime PM accordingly. > > > > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> > > --- > > > > Lorenzo, Sudeep, Rafael, Daniel, > > > > Note that, this patch is based upon a recently posted series [1] and the intent > > is to queue it on top. I can fold it into the series and resend it all, if that > > makes it easier for people. Just tell me what you prefer. > > > > Kind regards > > Uffe > > > > [1] > > https://patchwork.kernel.org/cover/11263735/ > > > > --- > > drivers/cpuidle/cpuidle-psci.c | 45 +++++++++++++++++++++++++++++++++- > > include/linux/cpuhotplug.h | 1 + > > 2 files changed, 45 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c > > index 835c7c3aa118..46b481c524cc 100644 > > --- a/drivers/cpuidle/cpuidle-psci.c > > +++ b/drivers/cpuidle/cpuidle-psci.c > > @@ -8,6 +8,7 @@ > > > > #define pr_fmt(fmt) "CPUidle PSCI: " fmt > > > > +#include <linux/cpuhotplug.h> > > #include <linux/cpuidle.h> > > #include <linux/cpumask.h> > > #include <linux/cpu_pm.h> > > @@ -31,6 +32,7 @@ struct psci_cpuidle_data { > > > > static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data); > > static DEFINE_PER_CPU(u32, domain_state); > > +static bool psci_cpuidle_use_cpuhp; > > > > void psci_set_domain_state(u32 state) > > { > > @@ -72,6 +74,44 @@ static int psci_enter_domain_idle_state(struct cpuidle_device *dev, > > return ret; > > } > > > > +static int psci_idle_cpuhp_up(unsigned int cpu) > > +{ > > + struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); > > + > > + if (pd_dev) > > + pm_runtime_get_sync(pd_dev); > > + > > + return 0; > > +} > > + > > +static int psci_idle_cpuhp_down(unsigned int cpu) > > +{ > > + struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); > > + > > + if (pd_dev) { > > + pm_runtime_put_sync(pd_dev); > > + /* Clear domain state to start fresh at next online. */ > > + psci_set_domain_state(0); > > + } > > + > > + return 0; > > +} > > + > > +static void psci_idle_init_cpuhp(void) > > +{ > > + int err; > > + > > + if (!psci_cpuidle_use_cpuhp) > > + return; > > + > > + err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING, > > + "cpuidle/psci:online", > > + psci_idle_cpuhp_up, > > + psci_idle_cpuhp_down); > > I would make it a cpuhp_setup_state() call and remove > > if (cpu_online(cpu)) > pm_runtime_get_sync_dev(dev); > > in check in psci_dt_attach_cpu(). > > Lorenzo Thanks for the suggestion, but that doesn't work when CONFIG_CPU_HOTPLUG is unset. As a matter of fact, I just realized that I haven't tried to compile without that Kconfig option. I should probably add a stub for psci_idle_init_cpuhp() to address that. > > > + if (err) > > + pr_warn("Failed %d while setup cpuhp state\n", err); > > +} > > + > > static int psci_enter_idle_state(struct cpuidle_device *dev, > > struct cpuidle_driver *drv, int idx) > > { > > @@ -161,9 +201,11 @@ static int __init psci_dt_cpu_init_idle(struct cpuidle_driver *drv, > > } > > > > /* Manage the deepest state via a dedicated enter-function. */ > > - if (dev) > > + if (dev) { > > drv->states[state_count - 1].enter = > > psci_enter_domain_idle_state; > > + psci_cpuidle_use_cpuhp = true; > > + } > > > > data->dev = dev; > > > > @@ -285,6 +327,7 @@ static int __init psci_idle_init(void) > > goto out_fail; > > } > > > > + psci_idle_init_cpuhp(); > > return 0; > > > > out_fail: > > diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h > > index e51ee772b9f5..01f04ed6ad92 100644 > > --- a/include/linux/cpuhotplug.h > > +++ b/include/linux/cpuhotplug.h > > @@ -95,6 +95,7 @@ enum cpuhp_state { > > CPUHP_AP_OFFLINE, > > CPUHP_AP_SCHED_STARTING, > > CPUHP_AP_RCUTREE_DYING, > > + CPUHP_AP_CPU_PM_STARTING, > > CPUHP_AP_IRQ_GIC_STARTING, > > CPUHP_AP_IRQ_HIP04_STARTING, > > CPUHP_AP_IRQ_ARMADA_XP_STARTING, > > -- > > 2.17.1 > > Kind regards Uffe
diff --git a/drivers/cpuidle/cpuidle-psci.c b/drivers/cpuidle/cpuidle-psci.c index 835c7c3aa118..46b481c524cc 100644 --- a/drivers/cpuidle/cpuidle-psci.c +++ b/drivers/cpuidle/cpuidle-psci.c @@ -8,6 +8,7 @@ #define pr_fmt(fmt) "CPUidle PSCI: " fmt +#include <linux/cpuhotplug.h> #include <linux/cpuidle.h> #include <linux/cpumask.h> #include <linux/cpu_pm.h> @@ -31,6 +32,7 @@ struct psci_cpuidle_data { static DEFINE_PER_CPU_READ_MOSTLY(struct psci_cpuidle_data, psci_cpuidle_data); static DEFINE_PER_CPU(u32, domain_state); +static bool psci_cpuidle_use_cpuhp; void psci_set_domain_state(u32 state) { @@ -72,6 +74,44 @@ static int psci_enter_domain_idle_state(struct cpuidle_device *dev, return ret; } +static int psci_idle_cpuhp_up(unsigned int cpu) +{ + struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); + + if (pd_dev) + pm_runtime_get_sync(pd_dev); + + return 0; +} + +static int psci_idle_cpuhp_down(unsigned int cpu) +{ + struct device *pd_dev = __this_cpu_read(psci_cpuidle_data.dev); + + if (pd_dev) { + pm_runtime_put_sync(pd_dev); + /* Clear domain state to start fresh at next online. */ + psci_set_domain_state(0); + } + + return 0; +} + +static void psci_idle_init_cpuhp(void) +{ + int err; + + if (!psci_cpuidle_use_cpuhp) + return; + + err = cpuhp_setup_state_nocalls(CPUHP_AP_CPU_PM_STARTING, + "cpuidle/psci:online", + psci_idle_cpuhp_up, + psci_idle_cpuhp_down); + if (err) + pr_warn("Failed %d while setup cpuhp state\n", err); +} + static int psci_enter_idle_state(struct cpuidle_device *dev, struct cpuidle_driver *drv, int idx) { @@ -161,9 +201,11 @@ static int __init psci_dt_cpu_init_idle(struct cpuidle_driver *drv, } /* Manage the deepest state via a dedicated enter-function. */ - if (dev) + if (dev) { drv->states[state_count - 1].enter = psci_enter_domain_idle_state; + psci_cpuidle_use_cpuhp = true; + } data->dev = dev; @@ -285,6 +327,7 @@ static int __init psci_idle_init(void) goto out_fail; } + psci_idle_init_cpuhp(); return 0; out_fail: diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index e51ee772b9f5..01f04ed6ad92 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -95,6 +95,7 @@ enum cpuhp_state { CPUHP_AP_OFFLINE, CPUHP_AP_SCHED_STARTING, CPUHP_AP_RCUTREE_DYING, + CPUHP_AP_CPU_PM_STARTING, CPUHP_AP_IRQ_GIC_STARTING, CPUHP_AP_IRQ_HIP04_STARTING, CPUHP_AP_IRQ_ARMADA_XP_STARTING,
When the hierarchical CPU topology is used and when a CPU is put offline, that CPU prevents its PM domain from being powered off, which is because genpd observes the corresponding attached device as being active from a runtime PM point of view. Furthermore, any potential master PM domains are also prevented from being powered off. To address this limitation, let's add add a new CPU hotplug state (CPUHP_AP_CPU_PM_STARTING) and register up/down callbacks for it, which allows us to deal with runtime PM accordingly. Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> --- Lorenzo, Sudeep, Rafael, Daniel, Note that, this patch is based upon a recently posted series [1] and the intent is to queue it on top. I can fold it into the series and resend it all, if that makes it easier for people. Just tell me what you prefer. Kind regards Uffe [1] https://patchwork.kernel.org/cover/11263735/ --- drivers/cpuidle/cpuidle-psci.c | 45 +++++++++++++++++++++++++++++++++- include/linux/cpuhotplug.h | 1 + 2 files changed, 45 insertions(+), 1 deletion(-) -- 2.17.1