Re: [Xen-devel] [PATCHv6 2/2] x86/ept: defer the invalidation until the p2m lock is released

[David Vrabel <david.vrabel@xxxxxxxxxx>]

On 20/12/15 06:56, Tian, Kevin wrote:
>> From: David Vrabel [mailto:david.vrabel@xxxxxxxxxx]
>> Sent: Friday, December 18, 2015 9:51 PM
>>
>> Holding the p2m lock while calling ept_sync_domain() is very expensive
>> since it does a on_selected_cpus() call.  IPIs on many socket machines
>> can be very slows and on_selected_cpus() is serialized.
>>
>> It is safe to defer the invalidate until the p2m lock is released
>> except for two cases:
>>
>> 1. When freeing a page table page (since partial translations may be
>>    cached).
>> 2. When reclaiming a zero page as part of PoD.
>>
>> For these cases, add p2m_tlb_flush_sync() calls which will immediately
>> perform the invalidate before the page is freed or reclaimed.
>>
>> Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
> 
> In a quick glimpse the patch is OK. Will find a time to think about it more
> carefully since this part is tricky (also allow others to comment before
> my ack in EPT part).

Ping?  Did you get more time to think about this patch?

David

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