aboutsummaryrefslogtreecommitdiff
path: root/kernel
diff options
context:
space:
mode:
authorPeter Zijlstra <peterz@infradead.org>2011-12-15 11:47:00 -0800
committerIngo Molnar <mingo@elte.hu>2011-12-16 09:44:58 +0100
commitab2789213d224202237292d78aaa0c386c7b28b2 (patch)
treeda6a28ca9a2eddad554742361e496764f17682a3 /kernel
parent75fc2d3797c47f5f70ca71c41c342c352845cd06 (diff)
sched: Fix select_idle_sibling() regression in selecting an idle SMT sibling
Mike Galbraith reported that this recent commit: commit 4dcfe1025b513c2c1da5bf5586adb0e80148f612 Author: Peter Zijlstra <peterz@infradead.org> Date: Thu Nov 10 13:01:10 2011 +0100 sched: Avoid SMT siblings in select_idle_sibling() if possible stopped selecting an idle SMT sibling when there are no idle cores in a single socket system. Intent of the select_idle_sibling() was to fallback to an idle SMT sibling, if it fails to identify an idle core. But this fallback was not happening on systems where all the scheduler domains had `SD_SHARE_PKG_RESOURCES' flag set. Fix it. Slightly bigger patch of cleaning all these goto's etc is queued up for the next release. Reported-by: Mike Galbraith <efault@gmx.de> Reported-by: Alex Shi <alex.shi@intel.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Link: http://lkml.kernel.org/r/1323978421.1984.244.camel@sbsiddha-desk.sc.intel.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched_fair.c14
1 files changed, 8 insertions, 6 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index a78ed2736ba..8a39fa3e3c6 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -2352,13 +2352,11 @@ again:
if (!smt && (sd->flags & SD_SHARE_CPUPOWER))
continue;
- if (!(sd->flags & SD_SHARE_PKG_RESOURCES)) {
- if (!smt) {
- smt = 1;
- goto again;
- }
+ if (smt && !(sd->flags & SD_SHARE_CPUPOWER))
+ break;
+
+ if (!(sd->flags & SD_SHARE_PKG_RESOURCES))
break;
- }
sg = sd->groups;
do {
@@ -2378,6 +2376,10 @@ next:
sg = sg->next;
} while (sg != sd->groups);
}
+ if (!smt) {
+ smt = 1;
+ goto again;
+ }
done:
rcu_read_unlock();