[PATCH 05/16] sched: Introduce SD_ASYM_CPUCAPACITY sched_domain topology flag

Morten Rasmussen
2016-05-23T10:58:34Z

Add a topology flag to the sched_domain hierarchy indicating which
domains span cpus of different capacity (e.g. big.LITTLE). This
information is currently only available through iterating through the
capacities of all the cpus.

cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>

Signed-off-by: Morten Rasmussen <morten.rasmussen@arm.com>
---
include/linux/sched.h | 1 +
kernel/sched/core.c | 6 +++++-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 463b91f..37752db 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1015,6 +1015,7 @@ extern void wake_up_q(struct wake_q_head *head);
#define SD_BALANCE_FORK 0x0008 /* Balance on fork, clone */
#define SD_BALANCE_WAKE 0x0010 /* Balance on wakeup */
#define SD_WAKE_AFFINE 0x0020 /* Wake task to waking CPU */
+#define SD_ASYM_CPUCAPACITY 0x0040 /* Domain contains cpus of different capacity*/
#define SD_SHARE_CPUCAPACITY 0x0080 /* Domain members share cpu capacity */
#define SD_SHARE_POWERDOMAIN 0x0100 /* Domain members share power domain */
#define SD_SHARE_PKG_RESOURCES 0x0200 /* Domain members share cpu pkg resources */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 404c078..d9619a3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5659,6 +5659,7 @@ static int sd_degenerate(struct sched_domain *sd)
SD_BALANCE_FORK |
SD_BALANCE_EXEC |
SD_SHARE_CPUCAPACITY |
+ SD_ASYM_CPUCAPACITY |
SD_SHARE_PKG_RESOURCES |
SD_SHARE_POWERDOMAIN)) {
if (sd->groups != sd->groups->next)
@@ -5689,6 +5690,7 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
SD_BALANCE_NEWIDLE |
SD_BALANCE_FORK |
SD_BALANCE_EXEC |
+ SD_ASYM_CPUCAPACITY |
SD_SHARE_CPUCAPACITY |
SD_SHARE_PKG_RESOURCES |
SD_PREFER_SIBLING |
@@ -6303,14 +6305,16 @@ static int sched_domains_curr_level;
* SD_NUMA - describes NUMA topologies
* SD_SHARE_POWERDOMAIN - describes shared power domain
*
- * Odd one out:
+ * Odd ones out:
* SD_ASYM_PACKING - describes SMT quirks
+ * SD_ASYM_CPUCAPACITY - describes mixed capacity topologies
*/
#define TOPOLOGY_SD_FLAGS \
(SD_SHARE_CPUCAPACITY | \
SD_SHARE_PKG_RESOURCES | \
SD_NUMA | \
SD_ASYM_PACKING | \
+ SD_ASYM_CPUCAPACITY | \
SD_SHARE_POWERDOMAIN)

static struct sched_domain *
--
1.9.1