Messages in this thread | | | Date | Mon, 19 Nov 2007 20:31:26 +0530 | From | Srivatsa Vaddagiri <> | Subject | Re: [PATCH 1/2] sched: Minor cleanups |
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On Mon, Nov 19, 2007 at 02:08:03PM +0100, Ingo Molnar wrote: > > #define for_each_leaf_cfs_rq(rq, cfs_rq) \ > > - list_for_each_entry(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) > > + list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list) > > > > /* Do the two (enqueued) entities belong to the same group ? */ > > static inline int > > @@ -1126,7 +1126,10 @@ static void print_cfs_stats(struct seq_f > > #ifdef CONFIG_FAIR_GROUP_SCHED > > print_cfs_rq(m, cpu, &cpu_rq(cpu)->cfs); > > #endif > > + > > + rcu_read_lock(); > > for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) > > print_cfs_rq(m, cpu, cfs_rq); > > + rcu_read_unlock(); > > hm, why is this a cleanup?
Sorry for the wrong subject. It was supposed to include the above bug fix, related to how we walk the task group list.
Thinking abt it now, I realize that print_cfs_rq() can potentially sleep and hence it cannot be surrounded by rcu_read_lock()/unlock().
And as Dipankar just pointed me, sched_create/destroy_group aren't serialized at all currently, so we need a mutex to protect them. The same mutex can be then used when walking the list in print_cfs_stats() ..
Will send update patches soon ..
-- Regards, vatsa - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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