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authorTim Blechmann2009-11-24 11:55:27 +0100
committerIngo Molnar2009-11-24 12:18:42 +0100
commit710390d90f143a9ebb87a475215140f426792efd (patch)
tree53b2019edf0d25f3530e0c169ec01e7e115125d1 /kernel/sched.c
parentsched: Optimize branch hint in pick_next_task_fair() (diff)
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sched: Optimize branch hint in context_switch()
Branch hint profiling on my nehalem machine showed over 90% incorrect branch hints: 10420275 170645395 94 context_switch sched.c 3043 10408421 171098521 94 context_switch sched.c 3050 Signed-off-by: Tim Blechmann <tim@klingt.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4B0BBB9F.6080304@klingt.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 93474a7935ae..010d5e16b4c5 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2829,14 +2829,14 @@ context_switch(struct rq *rq, struct task_struct *prev,
*/
arch_start_context_switch(prev);
- if (unlikely(!mm)) {
+ if (likely(!mm)) {
next->active_mm = oldmm;
atomic_inc(&oldmm->mm_count);
enter_lazy_tlb(oldmm, next);
} else
switch_mm(oldmm, mm, next);
- if (unlikely(!prev->mm)) {
+ if (likely(!prev->mm)) {
prev->active_mm = NULL;
rq->prev_mm = oldmm;
}