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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-01-28 14:51:40 +0100
committerIngo Molnar <mingo@elte.hu>2009-02-01 10:49:51 +0100
commita571bbeafbcc501d9989fbce1cddcd810bd51d71 (patch)
treecbfc71ece2ae3e351424d5f7ca9d8fff2429827b /kernel
parenta9f3e2b549f83a9cdab873abf4140be27c05a3f2 (diff)
downloadop-kernel-dev-a571bbeafbcc501d9989fbce1cddcd810bd51d71.zip
op-kernel-dev-a571bbeafbcc501d9989fbce1cddcd810bd51d71.tar.gz
sched: fix buddie group latency
Similar to the previous patch, by not clearing buddies we can select entities past their run quota, which can increase latency. This means we have to clear group buddies as well. Do not use the group clear for pick_next_task(), otherwise that'll get O(n^2). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched_fair.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 75248b9..a7e50ba 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -719,7 +719,7 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int wakeup)
__enqueue_entity(cfs_rq, se);
}
-static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+static void __clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
if (cfs_rq->last == se)
cfs_rq->last = NULL;
@@ -728,6 +728,12 @@ static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
cfs_rq->next = NULL;
}
+static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ for_each_sched_entity(se)
+ __clear_buddies(cfs_rq_of(se), se);
+}
+
static void
dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
{
@@ -1455,7 +1461,7 @@ static struct task_struct *pick_next_task_fair(struct rq *rq)
* If se was a buddy, clear it so that it will have to earn
* the favour again.
*/
- clear_buddies(cfs_rq, se);
+ __clear_buddies(cfs_rq, se);
set_next_entity(cfs_rq, se);
cfs_rq = group_cfs_rq(se);
} while (cfs_rq);
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