[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] xen kernel crash at boot since 23598:b24018319772
>>> On 30.06.11 at 16:21, Keir Fraser <keir.xen@xxxxxxxxx> wrote: > On 30/06/2011 13:43, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote: >> That's likely not the one, but rather 23573:584c2e5e03d9. And >> indeed it seems like the assertion is a stale leftover from the >> original non-RCU version of the patch. There are a few more >> similar ones which may similarly be candidates fro removal. >> >> Keir, what's your take on this? > > Not sure, pirq_spin_lock_irq_desc() has a comment about the event_lock > preventing the PIRQ-IRQ mapping from changing under its feet. Why would the > radix-tree patch change what code is protected by event_lock, anyway? The whole function (including the comment) got added by that patch. Hence either comment and assertion need fixing, or both need to stay and calling code needs adjustment. The RCU-ness, as I understand it, allows read accesses to the PIRQ -> IRQ mapping to be done lockless, hence d->event_lock needs to be held only if the intention is to alter the mapping (which in particular isn't the case when unmasking an IRQ). Or did I still not get my RCU thinking right? Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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