Messages in this thread | | | Date | Thu, 19 Mar 2009 14:26:28 +0530 | From | Dipankar Sarma <> | Subject | Re: Question about usage of RCU in the input layer |
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On Wed, Mar 18, 2009 at 09:58:12PM -0700, Arjan van de Ven wrote: > Hi, > > the input layer does a "synchronize_rcu()" after a list_add_tail_rcu(), which > is costing me 1 second of boot time..... > And based on my understanding of the RCU concept, you only need to synchronize on delete, > not on addition... so I think the synchronize is entirely redundant here... >
The more appropriate question is - why is synchronize_rcu() taking 1 second ? Any idea what the other CPUs are doing at the time of calling synchronize_rcu() ? What driver is this ? How early in the boot is this happening ?
Thanks Dipankar
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