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SubjectRe: [PATCH v2 5/7] sched: add a new SD_SHARE_POWERDOMAIN for sched_domain
Hi Vincent,

On 03/18/2014 11:26 PM, Vincent Guittot wrote:
> 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.

I don't see this flag being set either in sd_init() or in
default_topology[]. Should not the default_topology[] flag setting
routines set this flag at every level of sched domain along with other
topology flags, unless the arch wants to override it?

Regards
Preeti U Murthy
> This flag is part of the topology flags that can be set by arch.
>
> 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 6479de4..7048369 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 0b51ee3..224ec3b 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -5298,7 +5298,8 @@ 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;
> }
> @@ -5329,7 +5330,8 @@ 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;
> }
> @@ -5946,7 +5948,8 @@ static int sched_domains_curr_level;
> (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)
>



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