Messages in this thread |  | | Date | Wed, 4 Apr 2007 12:57:00 +0400 | | From | Oleg Nesterov <> | | Subject | Re: getting processor numbers |
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On 04/04, Ingo Molnar wrote: > > * Oleg Nesterov <oleg@tv-sign.ru> wrote: > > > But we don't need tasklist_lock at all, we can use > > rcu_read_lock/unlock. Q: don't we need task_rq_lock() to read > > ->cpus_allowed "atomically" ? > > right now ->cpus_allowed is protected by tasklist_lock. We cannot do RCU > here because ->cpus_allowed modifications are not RCUified.
Is it so? that was my question. Afaics, set_cpus_allowed() does p->cpus_allowed = new_mask under rq->lock, so I don't understand how tasklist_lock can help.
Could you clarify?
Oleg.
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