| Message ID | 20190214182910.20600-1-sudeep.holla@arm.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Delegated to: | Rafael Wysocki |
| Headers | show |
| Series | [v3] drivers: base: add support to skip power management in device/driver model | expand |
Hello Sudeep, On Thu, Feb 14, 2019 at 06:29:10PM +0000, Sudeep Holla wrote: [..] > > Lets add no_pm_required flags to indicate that the device doesn't s/no_pm_required/no_pm/ ? > require any sort of pm activities and all of them can be completely > skipped. We can use the same flag to also avoid adding not used *power* > sysfs entries for these devices. For now, lets use this for cpu cache > devices. [..] Running suspend/resume ~500 times on H3-Salvator-X with this patch didn't reveal any regressions. The annoying warnings are gone. Console log and .config are available at: https://gist.github.com/erosca/1af11aa62e16903e1b6964be6a9eea77 Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com> Thanks! Eugeniu.
On Thursday, February 14, 2019 7:29:10 PM CET Sudeep Holla wrote: > All device objects in the driver model contain fields that control the > handling of various power management activities. However, it's not > always useful. There are few instances where pseudo devices are added > to the model just to take advantage of many other features like > kobjects, udev events, and so on. One such example is cpu devices and > their caches. > > The sysfs for the cpu caches are managed by adding devices with cpu > as the parent in cpu_device_create() when secondary cpu is brought > online. Generally when the secondary CPUs are hotplugged back in as part > of resume from suspend-to-ram, we call cpu_device_create() from the cpu > hotplug state machine while the cpu device associated with that CPU is > not yet ready to be resumed as the device_resume() call happens bit > later. It's not really needed to set the flag is_prepared for cpu > devices as they are mostly pseudo device and hotplug framework deals > with state machine and not managed through the cpu device. > > This often results in annoying warning when resuming: > Enabling non-boot CPUs ... > CPU1: Booted secondary processor > cache: parent cpu1 should not be sleeping > CPU1 is up > CPU2: Booted secondary processor > cache: parent cpu2 should not be sleeping > CPU2 is up > .... and so on. > > So in order to fix these kind of errors, we could just completely avoid > doing any power management related initialisations and operations if > they are not used by these devices. > > Lets add no_pm_required flags to indicate that the device doesn't > require any sort of pm activities and all of them can be completely > skipped. We can use the same flag to also avoid adding not used *power* > sysfs entries for these devices. For now, lets use this for cpu cache > devices. > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Cc: "Rafael J. Wysocki" <rafael@kernel.org> > Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> > Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> > --- > drivers/base/cpu.c | 1 + > drivers/base/power/main.c | 7 +++++++ > drivers/base/power/sysfs.c | 6 ++++++ > include/linux/device.h | 10 ++++++++++ > include/linux/pm.h | 1 + > 5 files changed, 25 insertions(+) > > v2->v3: > - renamed no_pm_required to no_pm > - fixed the wrong comment in device_pm_add > - add missing check in dpm_sysfs_remove reported by Eugeniu > - added Ulf's reviewed-by tag > > v1->v2: > - dropped setting the flag for cpu devices, for now just cpu caches > will make use of this new flag. > > RFC->v1: > - dropped the idea of adding cpu hotplug callback to deal just > with cpu devices, instead add a new flag in the device pm_info > structure > > [RFC] : https://marc.info/?l=linux-pm&m=154842896407904&w=2 > [v1] : https://marc.info/?l=linux-pm&m=154946578717730&w=2 > [v2] : https://marc.info/?l=linux-pm&m=155005931507485&w=2 > > diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c > index eb9443d5bae1..6ce93a52bf3f 100644 > --- a/drivers/base/cpu.c > +++ b/drivers/base/cpu.c > @@ -427,6 +427,7 @@ __cpu_device_create(struct device *parent, void *drvdata, > dev->parent = parent; > dev->groups = groups; > dev->release = device_create_release; > + device_set_pm_not_required(dev); > dev_set_drvdata(dev, drvdata); > > retval = kobject_set_name_vargs(&dev->kobj, fmt, args); > diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c > index 0992e67e862b..6a473004abe6 100644 > --- a/drivers/base/power/main.c > +++ b/drivers/base/power/main.c > @@ -124,6 +124,10 @@ void device_pm_unlock(void) > */ > void device_pm_add(struct device *dev) > { > + /* Skip pm setup/initialisation */ > + if (device_pm_not_required(dev)) > + return; > + > pr_debug("PM: Adding info for %s:%s\n", > dev->bus ? dev->bus->name : "No Bus", dev_name(dev)); > device_pm_check_callbacks(dev); > @@ -142,6 +146,9 @@ void device_pm_add(struct device *dev) > */ > void device_pm_remove(struct device *dev) > { > + if (device_pm_not_required(dev)) > + return; > + > pr_debug("PM: Removing info for %s:%s\n", > dev->bus ? dev->bus->name : "No Bus", dev_name(dev)); > complete_all(&dev->power.completion); > diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c > index d713738ce796..5e8d4867c4da 100644 > --- a/drivers/base/power/sysfs.c > +++ b/drivers/base/power/sysfs.c > @@ -648,6 +648,10 @@ int dpm_sysfs_add(struct device *dev) > { > int rc; > > + /* No need to create pm sysfs if explicitly disabled */ > + if (device_pm_not_required(dev)) > + return 0; > + > rc = sysfs_create_group(&dev->kobj, &pm_attr_group); > if (rc) > return rc; > @@ -727,6 +731,8 @@ void rpm_sysfs_remove(struct device *dev) > > void dpm_sysfs_remove(struct device *dev) > { > + if (device_pm_not_required(dev)) > + return; > sysfs_unmerge_group(&dev->kobj, &pm_qos_latency_tolerance_attr_group); > dev_pm_qos_constraints_destroy(dev); > rpm_sysfs_remove(dev); > diff --git a/include/linux/device.h b/include/linux/device.h > index 6cb4640b6160..53028636fe39 100644 > --- a/include/linux/device.h > +++ b/include/linux/device.h > @@ -1165,6 +1165,16 @@ static inline bool device_async_suspend_enabled(struct device *dev) > return !!dev->power.async_suspend; > } > > +static inline bool device_pm_not_required(struct device *dev) > +{ > + return dev->power.no_pm; > +} > + > +static inline void device_set_pm_not_required(struct device *dev) > +{ > + dev->power.no_pm = true; > +} > + > static inline void dev_pm_syscore_device(struct device *dev, bool val) > { > #ifdef CONFIG_PM_SLEEP > diff --git a/include/linux/pm.h b/include/linux/pm.h > index 0bd9de116826..8869ce7b5fa6 100644 > --- a/include/linux/pm.h > +++ b/include/linux/pm.h > @@ -592,6 +592,7 @@ struct dev_pm_info { > bool is_suspended:1; /* Ditto */ > bool is_noirq_suspended:1; > bool is_late_suspended:1; > + bool no_pm:1; > bool early_init:1; /* Owned by the PM core */ > bool direct_complete:1; /* Owned by the PM core */ > u32 driver_flags; > -- Applied, thanks!
diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index eb9443d5bae1..6ce93a52bf3f 100644 --- a/drivers/base/cpu.c +++ b/drivers/base/cpu.c @@ -427,6 +427,7 @@ __cpu_device_create(struct device *parent, void *drvdata, dev->parent = parent; dev->groups = groups; dev->release = device_create_release; + device_set_pm_not_required(dev); dev_set_drvdata(dev, drvdata); retval = kobject_set_name_vargs(&dev->kobj, fmt, args); diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 0992e67e862b..6a473004abe6 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -124,6 +124,10 @@ void device_pm_unlock(void) */ void device_pm_add(struct device *dev) { + /* Skip pm setup/initialisation */ + if (device_pm_not_required(dev)) + return; + pr_debug("PM: Adding info for %s:%s\n", dev->bus ? dev->bus->name : "No Bus", dev_name(dev)); device_pm_check_callbacks(dev); @@ -142,6 +146,9 @@ void device_pm_add(struct device *dev) */ void device_pm_remove(struct device *dev) { + if (device_pm_not_required(dev)) + return; + pr_debug("PM: Removing info for %s:%s\n", dev->bus ? dev->bus->name : "No Bus", dev_name(dev)); complete_all(&dev->power.completion); diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c index d713738ce796..5e8d4867c4da 100644 --- a/drivers/base/power/sysfs.c +++ b/drivers/base/power/sysfs.c @@ -648,6 +648,10 @@ int dpm_sysfs_add(struct device *dev) { int rc; + /* No need to create pm sysfs if explicitly disabled */ + if (device_pm_not_required(dev)) + return 0; + rc = sysfs_create_group(&dev->kobj, &pm_attr_group); if (rc) return rc; @@ -727,6 +731,8 @@ void rpm_sysfs_remove(struct device *dev) void dpm_sysfs_remove(struct device *dev) { + if (device_pm_not_required(dev)) + return; sysfs_unmerge_group(&dev->kobj, &pm_qos_latency_tolerance_attr_group); dev_pm_qos_constraints_destroy(dev); rpm_sysfs_remove(dev); diff --git a/include/linux/device.h b/include/linux/device.h index 6cb4640b6160..53028636fe39 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1165,6 +1165,16 @@ static inline bool device_async_suspend_enabled(struct device *dev) return !!dev->power.async_suspend; } +static inline bool device_pm_not_required(struct device *dev) +{ + return dev->power.no_pm; +} + +static inline void device_set_pm_not_required(struct device *dev) +{ + dev->power.no_pm = true; +} + static inline void dev_pm_syscore_device(struct device *dev, bool val) { #ifdef CONFIG_PM_SLEEP diff --git a/include/linux/pm.h b/include/linux/pm.h index 0bd9de116826..8869ce7b5fa6 100644 --- a/include/linux/pm.h +++ b/include/linux/pm.h @@ -592,6 +592,7 @@ struct dev_pm_info { bool is_suspended:1; /* Ditto */ bool is_noirq_suspended:1; bool is_late_suspended:1; + bool no_pm:1; bool early_init:1; /* Owned by the PM core */ bool direct_complete:1; /* Owned by the PM core */ u32 driver_flags;