diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2011-04-05 17:23:53 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2011-04-14 08:52:39 +0200 |
| commit | 8f42ced974df7d5af2de4cf5ea21fe978c7e4478 (patch) | |
| tree | 514ee978491dc62ee727308be1f228987c47eb54 /kernel | |
| parent | ab2515c4b98f7bc4fa11cad9fa0f811d63a72a26 (diff) | |
sched: Drop rq->lock from sched_exec()
Since we can now call select_task_rq() and set_task_cpu() with only
p->pi_lock held, and sched_exec() load-balancing has always been
optimistic, drop all rq->lock usage.
Oleg also noted that need_migrate_task() will always be true for
current, so don't bother calling that at all.
Reviewed-by: Frank Rowand <frank.rowand@am.sony.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20110405152729.314204889@chello.nl
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched.c | 15 |
1 files changed, 5 insertions, 10 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 7c5494dccd3..1be1a09b9dc 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -3465,27 +3465,22 @@ void sched_exec(void) { struct task_struct *p = current; unsigned long flags; - struct rq *rq; int dest_cpu; - rq = task_rq_lock(p, &flags); + raw_spin_lock_irqsave(&p->pi_lock, flags); dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0); if (dest_cpu == smp_processor_id()) goto unlock; - /* - * select_task_rq() can race against ->cpus_allowed - */ - if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed) && - likely(cpu_active(dest_cpu)) && need_migrate_task(p)) { + if (likely(cpu_active(dest_cpu))) { struct migration_arg arg = { p, dest_cpu }; - task_rq_unlock(rq, p, &flags); - stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); + stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); return; } unlock: - task_rq_unlock(rq, p, &flags); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); } #endif |