Re: [Xen-devel] [PATCH] x86/mm: Improve ring management for memory events. Do not lose guest events

["Andres Lagar-Cavilla" <andres@xxxxxxxxxxxxxxxx>]

> On Wed, Jan 11, Andres Lagar-Cavilla wrote:
>
>> @@ -898,7 +902,7 @@ void p2m_mem_paging_drop_page(struct dom
>>   * already sent to the pager. In this case the caller has to try again
>> until the
>>   * gfn is fully paged in again.
>>   */
>> -void p2m_mem_paging_populate(struct domain *d, unsigned long gfn)
>> +int p2m_mem_paging_populate(struct domain *d, unsigned long gfn)
>>  {
>>      struct vcpu *v = current;
>>      mem_event_request_t req;
>
> What is the reason to return an error here? None of the callers need to
> check it because they already know their condition (which is
> p2m_is_paging()). And your patch doesnt seem to update them. Foreigners
> try again, requests from the target domain do currently also try again
> until my change to use wait queues in gfn_to_mfn* is finished. And even
> then the call p2m_mem_paging_populate() will most likely remain a
> one-shot/must-succeed thing if the request is from the target domain.
>
> The only condition to care about in p2m_mem_paging_populate() is -ENOSYS
> from mem_event_claim_slot(), which your patch already handles by
> crashing the guest. Since the guest is in an kind-of undefined state
> anyway if the pager disappears while some gfns are still in paging state,
> this is one of the possible actions.

Ok, we'll make it void. Anything else pending?
Thanks
Andres
> Olaf
>



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel