Re: [RFC PATCH 1/2] x86/ibpb: Skip IBPB when we switch back to same user process

[Tim Chen]

On 01/25/2018 02:01 PM, Andy Lutomirski wrote:
> On Thu, Jan 25, 2018 at 1:57 PM, Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote:
>> Andy Lutomirski <luto@xxxxxxxxxx> writes:
>>>
>>> That being said, just stashing last_user_mm without any refcounting
>>> should be fine.
>>
>> If last_user_mm is freed and reallocated by a different process,
>> then that would miss the IPBP incorrectly.
>>
> 
> Hmm, right.  So ctx_id it is.
> 
> --Andy
> 
Thanks.  Using ctx_id is a pretty clean approach.  I will refresh
this patch and drop the second patch.

Tim