On Fri, Aug 3, 2018 at 1:43 PM, Ulf Hansson <[email protected]> wrote: > On 19 July 2018 at 12:25, Rafael J. Wysocki <[email protected]> wrote: >> On Wednesday, June 20, 2018 7:22:04 PM CEST Ulf Hansson wrote: >>> To enable a device belonging to a CPU to be attached to a PM domain managed >>> by genpd, let's do a few changes to genpd as to make it convenient to >>> manage the specifics around CPUs. >>> >>> First, as to be able to quickly find out what CPUs that are attached to a >>> genpd, which typically becomes useful from a genpd governor as following >>> changes is about to show, let's add a cpumask 'cpus' to the struct >>> generic_pm_domain. >>> >>> At the point when a device that belongs to a CPU, is attached/detached to >>> its corresponding PM domain via genpd_add_device(), let's update the >>> cpumask in genpd->cpus. Moreover, propagate the update of the cpumask to >>> the master domains, which makes the genpd->cpus to contain a cpumask that >>> hierarchically reflect all CPUs for a genpd, including CPUs attached to >>> subdomains. >>> >>> Second, to unconditionally manage CPUs and the cpumask in genpd->cpus, is >>> unnecessary for cases when only non-CPU devices are parts of a genpd. >>> Let's avoid this by adding a new configuration bit, GENPD_FLAG_CPU_DOMAIN. >>> Clients must set the bit before they call pm_genpd_init(), as to instruct >>> genpd that it shall deal with CPUs and thus manage the cpumask in >>> genpd->cpus. >>> >>> Cc: Lina Iyer <[email protected]> >>> Co-developed-by: Lina Iyer <[email protected]> >>> Signed-off-by: Ulf Hansson <[email protected]> >>> --- >>> drivers/base/power/domain.c | 69 ++++++++++++++++++++++++++++++++++++- >>> include/linux/pm_domain.h | 3 ++ >>> 2 files changed, 71 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c >>> index 21d298e1820b..6149ce0bfa7b 100644 >>> --- a/drivers/base/power/domain.c >>> +++ b/drivers/base/power/domain.c >>> @@ -20,6 +20,7 @@ >>> #include <linux/sched.h> >>> #include <linux/suspend.h> >>> #include <linux/export.h> >>> +#include <linux/cpu.h> >>> >>> #include "power.h" >>> >>> @@ -126,6 +127,7 @@ static const struct genpd_lock_ops genpd_spin_ops = { >>> #define genpd_is_irq_safe(genpd) (genpd->flags & GENPD_FLAG_IRQ_SAFE) >>> #define genpd_is_always_on(genpd) (genpd->flags & GENPD_FLAG_ALWAYS_ON) >>> #define genpd_is_active_wakeup(genpd) (genpd->flags & >>> GENPD_FLAG_ACTIVE_WAKEUP) >>> +#define genpd_is_cpu_domain(genpd) (genpd->flags & GENPD_FLAG_CPU_DOMAIN) >>> >>> static inline bool irq_safe_dev_in_no_sleep_domain(struct device *dev, >>> const struct generic_pm_domain *genpd) >>> @@ -1377,6 +1379,62 @@ 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) >>> +{ >>> + struct gpd_link *link; >>> + >>> + if (!genpd_is_cpu_domain(genpd)) >>> + return; >>> + >>> + list_for_each_entry(link, &genpd->slave_links, slave_node) { >>> + struct generic_pm_domain *master = link->master; >>> + >>> + genpd_lock_nested(master, depth + 1); >>> + __genpd_update_cpumask(master, cpu, set, depth + 1); >>> + genpd_unlock(master); >>> + } >>> + >>> + if (set) >>> + cpumask_set_cpu(cpu, genpd->cpus); >>> + else >>> + cpumask_clear_cpu(cpu, genpd->cpus); >>> +} >> >> As noted elsewhere, there is a concern about the possible weight of this >> cpumask and I think that it would be good to explicitly put a limit on it. > > I have been digesting your comments on the series, but wonder if this > is still a relevant concern?
Well, there are systems with very large cpumasks and it is sort of good to have that in mind when designing any code using them.
