Messages in this thread Patch in this message | | | From | Ulf Hansson <> | Date | Thu, 25 Apr 2019 12:14:30 +0200 | Subject | Re: [PATCH 3/4] PM / Domains: Search for the CPU device outside the genpd lock |
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On Thu, 25 Apr 2019 at 11:45, Viresh Kumar <viresh.kumar@linaro.org> wrote: > > On 25-04-19, 11:04, Ulf Hansson wrote: > > While attaching/detaching a device to a PM domain (genpd) that has the > > GENPD_FLAG_CPU_DOMAIN set, genpd iterates the cpu_possible_mask to check > > whether the device corresponds to a CPU. This iteration is done while > > holding the genpd's lock, which is unnecessary. Let's avoid the locking, > > by restructuring the corresponding code a bit. > > > > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> > > --- > > drivers/base/power/domain.c | 52 +++++++++++++++++++------------------ > > 1 file changed, 27 insertions(+), 25 deletions(-) > > > > diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c > > index 93298b7db408..da1c99178943 100644 > > --- a/drivers/base/power/domain.c > > +++ b/drivers/base/power/domain.c > > @@ -1450,8 +1450,8 @@ static void genpd_free_dev_data(struct device *dev, > > dev_pm_put_subsys_data(dev); > > } > > > > -static void __genpd_update_cpumask(struct generic_pm_domain *genpd, > > - int cpu, bool set, unsigned int depth) > > +static void genpd_update_cpumask(struct generic_pm_domain *genpd, > > + int cpu, bool set, unsigned int depth) > > { > > struct gpd_link *link; > > > > @@ -1462,7 +1462,7 @@ static void __genpd_update_cpumask(struct generic_pm_domain *genpd, > > struct generic_pm_domain *master = link->master; > > > > genpd_lock_nested(master, depth + 1); > > - __genpd_update_cpumask(master, cpu, set, depth + 1); > > + genpd_update_cpumask(master, cpu, set, depth + 1); > > genpd_unlock(master); > > } > > > > @@ -1472,38 +1472,37 @@ static void __genpd_update_cpumask(struct generic_pm_domain *genpd, > > cpumask_clear_cpu(cpu, genpd->cpus); > > } > > > > -static void genpd_update_cpumask(struct generic_pm_domain *genpd, > > - struct device *dev, bool set) > > +static void genpd_set_cpumask(struct generic_pm_domain *genpd, int cpu) > > +{ > > + if (cpu >= 0) > > + genpd_update_cpumask(genpd, cpu, true, 0); > > +} > > + > > +static void genpd_clear_cpumask(struct generic_pm_domain *genpd, int cpu) > > +{ > > + if (cpu >= 0) > > + genpd_update_cpumask(genpd, cpu, false, 0); > > +} > > + > > +static int genpd_get_cpu(struct generic_pm_domain *genpd, struct device *dev) > > { > > int cpu; > > > > if (!genpd_is_cpu_domain(genpd)) > > - return; > > + return -1; > > > > for_each_possible_cpu(cpu) { > > - if (get_cpu_device(cpu) == dev) { > > - __genpd_update_cpumask(genpd, cpu, set, 0); > > - return; > > - } > > + if (get_cpu_device(cpu) == dev) > > + return cpu; > > } > > -} > > > > -static void genpd_set_cpumask(struct generic_pm_domain *genpd, > > - struct device *dev) > > -{ > > - genpd_update_cpumask(genpd, dev, true); > > -} > > - > > -static void genpd_clear_cpumask(struct generic_pm_domain *genpd, > > - struct device *dev) > > -{ > > - genpd_update_cpumask(genpd, dev, false); > > + return -1; > > } > > > > static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev) > > { > > struct generic_pm_domain_data *gpd_data; > > - int ret; > > + int ret, cpu; > > > > dev_dbg(dev, "%s()\n", __func__); > > > > @@ -1514,13 +1513,15 @@ static int genpd_add_device(struct generic_pm_domain *genpd, struct device *dev) > > if (IS_ERR(gpd_data)) > > return PTR_ERR(gpd_data); > > > > + cpu = genpd_get_cpu(genpd, dev); > > + > > ret = genpd->attach_dev ? genpd->attach_dev(genpd, dev) : 0; > > if (ret) > > goto out; > > > > genpd_lock(genpd); > > > > - genpd_set_cpumask(genpd, dev); > > + genpd_set_cpumask(genpd, cpu); > > Should we check if "cpu" is valid here ? As that was done earlier.
This is being done in the new version of genpd_set|clear_cpumask(). Like below.
"if (cpu >= 0)"...
> > > dev_pm_domain_set(dev, &genpd->domain); > > > > genpd->device_count++; > > @@ -1560,13 +1561,14 @@ static int genpd_remove_device(struct generic_pm_domain *genpd, > > { > > struct generic_pm_domain_data *gpd_data; > > struct pm_domain_data *pdd; > > - int ret = 0; > > + int cpu, ret = 0; > > > > dev_dbg(dev, "%s()\n", __func__); > > > > pdd = dev->power.subsys_data->domain_data; > > gpd_data = to_gpd_data(pdd); > > dev_pm_qos_remove_notifier(dev, &gpd_data->nb); > > + cpu = genpd_get_cpu(genpd, dev); > > > > genpd_lock(genpd); > > > > @@ -1578,7 +1580,7 @@ static int genpd_remove_device(struct generic_pm_domain *genpd, > > genpd->device_count--; > > genpd->max_off_time_changed = true; > > > > - genpd_clear_cpumask(genpd, dev); > > + genpd_clear_cpumask(genpd, cpu); > > Same here.
See above.
> > > dev_pm_domain_set(dev, NULL); > > > > list_del_init(&pdd->list_node); > > -- > > 2.17.1 > > -- > viresh
Thanks for reviewing!
Kind regards Uffe
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