Re: [patch v4 02/18] sched: select_task_rq_fair clean up

2013-02-13 Thread Alex Shi
On 02/12/2013 06:14 PM, Peter Zijlstra wrote: > On Thu, 2013-01-24 at 11:06 +0800, Alex Shi wrote: >> It is impossible to miss a task allowed cpu in a eligible group. > > I suppose your reasoning goes like: tsk->cpus_allowed is protected by > ->pi_lock, we hold this, therefore it cannot change and

Re: [patch v4 02/18] sched: select_task_rq_fair clean up

2013-02-12 Thread Peter Zijlstra
On Thu, 2013-01-24 at 11:06 +0800, Alex Shi wrote: > It is impossible to miss a task allowed cpu in a eligible group. I suppose your reasoning goes like: tsk->cpus_allowed is protected by ->pi_lock, we hold this, therefore it cannot change and find_idlest_group() dtrt? We can then state that this

[patch v4 02/18] sched: select_task_rq_fair clean up

2013-01-23 Thread Alex Shi
It is impossible to miss a task allowed cpu in a eligible group. And since find_idlest_group only return a different group which excludes old cpu, it's also impossible to find a new cpu same as old cpu. Signed-off-by: Alex Shi Reviewed-by: Preeti U Murthy --- kernel/sched/fair.c | 5 - 1 f