[tip:sched/core] sched: Add SD_PREFER_SIBLING for SMT level

[tip-bot for Vincent Guittot <tipbot@zytor.com>]

Commit-ID:  caff37ef96eac7fe96a582d032f6958e834e9447
Gitweb:     http://git.kernel.org/tip/caff37ef96eac7fe96a582d032f6958e834e9447
Author:     Vincent Guittot <vincent.guittot@linaro.org>
AuthorDate: Fri, 27 Feb 2015 16:54:13 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Fri, 27 Mar 2015 09:36:05 +0100

sched: Add SD_PREFER_SIBLING for SMT level

Add the SD_PREFER_SIBLING flag for SMT level in order to ensure that
the scheduler will place at least one task per core.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Preeti U. Murthy <preeti@linux.vnet.ibm.com>
Cc: Morten.Rasmussen@arm.com
Cc: dietmar.eggemann@arm.com
Cc: efault@gmx.de
Cc: kamalesh@linux.vnet.ibm.com
Cc: linaro-kernel@lists.linaro.org
Cc: nicolas.pitre@linaro.org
Cc: riel@redhat.com
Link: http://lkml.kernel.org/r/1425052454-25797-11-git-send-email-vincent.guittot@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 838fc9d..043e2a1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6240,6 +6240,7 @@ sd_init(struct sched_domain_topology_level *tl, int cpu)
 	 */
 
 	if (sd->flags & SD_SHARE_CPUCAPACITY) {
+		sd->flags |= SD_PREFER_SIBLING;
 		sd->imbalance_pct = 110;
 		sd->smt_gain = 1178; /* ~15% */