Messages in this thread | | | Subject | Re: [PATCH v8 1/5] mm: introduce a common interface for balloon pages mobility | From | Peter Zijlstra <> | Date | Tue, 21 Aug 2012 17:16:06 +0200 |
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On Tue, 2012-08-21 at 16:52 +0300, Michael S. Tsirkin wrote: > > + rcu_read_lock(); > > + mapping = rcu_dereference(page->mapping); > > + if (mapping_balloon(mapping)) > > + ret = true; > > + rcu_read_unlock(); > > This looks suspicious: you drop rcu_read_unlock > so can't page switch from balloon to non balloon?
RCU read lock is a non-exclusive lock, it cannot avoid anything like that.
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