dect
/
linux-2.6
Archived
13
0
Fork 0
Code Releases Activity

sched: move_task_off_dead_cpu(): Remove retry logic 

The previous patch preserved the retry logic, but it looks unneeded.

__migrate_task() can only fail if we raced with migration after we dropped
the lock, but in this case the caller of set_cpus_allowed/etc must initiate
migration itself if ->on_rq == T.

We already fixed p->cpus_allowed, the changes in active/online masks must
be visible to racer, it should migrate the task to online cpu correctly.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100315091014.GA9138@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Oleg Nesterov 2010-03-15 10:10:14 +01:00 committed by Ingo Molnar
parent 1445c08d06
commit c1804d547d
1 changed files with 6 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
kernel/sched.c
View File

@ -5456,7 +5456,7 @@ static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
struct rq *rq = cpu_rq(dead_cpu);
int needs_cpu, uninitialized_var(dest_cpu);
unsigned long flags;
again:
local_irq_save(flags);
raw_spin_lock(&rq->lock);
@ -5464,14 +5464,13 @@ again:
if (needs_cpu)
dest_cpu = select_fallback_rq(dead_cpu, p);
raw_spin_unlock(&rq->lock);
/* It can have affinity changed while we were choosing. */
/*
* It can only fail if we race with set_cpus_allowed(),
* in the racer should migrate the task anyway.
*/
if (needs_cpu)
needs_cpu = !__migrate_task(p, dead_cpu, dest_cpu);
__migrate_task(p, dead_cpu, dest_cpu);
local_irq_restore(flags);
if (unlikely(needs_cpu))
goto again;
}
/*