A new flag SD_SHARE_POWERDOMAIN is created to reflect whether groups of CPUs in a sched_domain level can or not reach different power state. As an example, the flag should be cleared at CPU level if groups of cores can be power gated independently. This information can be used to add load balancing level between group of CPUs than can power gate independantly. The default behavior of the scheduler is to spread tasks across CPUs and groups of CPUs so the flag is set into all sched_domains.
Signed-off-by: Vincent Guittot vincent.guittot@linaro.org --- include/linux/sched.h | 1 + kernel/sched/core.c | 9 ++++++--- 2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h index dbc35dd..182a080 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -861,6 +861,7 @@ enum cpu_idle_type { #define SD_BALANCE_WAKE 0x0010 /* Balance on wakeup */ #define SD_WAKE_AFFINE 0x0020 /* Wake task to waking CPU */ #define SD_SHARE_CPUPOWER 0x0080 /* Domain members share cpu power */ +#define SD_SHARE_POWERDOMAIN 0x0100 /* Domain members share power domain */ #define SD_SHARE_PKG_RESOURCES 0x0200 /* Domain members share cpu pkg resources */ #define SD_SERIALIZE 0x0400 /* Only a single load balancing instance */ #define SD_ASYM_PACKING 0x0800 /* Place busy groups earlier in the domain */ diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 7606de0..b28cff0 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5283,7 +5283,8 @@ static int sd_degenerate(struct sched_domain *sd) SD_BALANCE_FORK | SD_BALANCE_EXEC | SD_SHARE_CPUPOWER | - SD_SHARE_PKG_RESOURCES)) { + SD_SHARE_PKG_RESOURCES | + SD_SHARE_POWERDOMAIN)) { if (sd->groups != sd->groups->next) return 0; } @@ -5314,7 +5315,8 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) SD_BALANCE_EXEC | SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES | - SD_PREFER_SIBLING); + SD_PREFER_SIBLING | + SD_SHARE_POWERDOMAIN); if (nr_node_ids == 1) pflags &= ~SD_SERIALIZE; } @@ -5932,7 +5934,8 @@ static struct cpumask ***sched_domains_numa_masks; (SD_SHARE_CPUPOWER | \ SD_SHARE_PKG_RESOURCES | \ SD_NUMA | \ - SD_ASYM_PACKING) + SD_ASYM_PACKING | \ + SD_SHARE_POWERDOMAIN)
static struct sched_domain * sd_init(struct sched_domain_topology_level *tl, int cpu)