Message-ID: <4AB8E2F1.6030401@redhat.com>
Date: Tue, 22 Sep 2009 17:45:05 +0300
From: Avi Kivity <avi@redhat.com>
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To: Ingo Molnar <mingo@elte.hu>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>, "H. Peter Anvin" <hpa@zytor.com>,
       linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
       Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: [PATCH v2] core, x86: Add user return notifiers
References: <4AB3CDEC.5050902@zytor.com> <1253342422-13811-1-git-send-email-avi@redhat.com> <4AB8980D.5070803@redhat.com> <20090922143223.GA31702@elte.hu>
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On 09/22/2009 05:32 PM, Ingo Molnar wrote:
> * Avi Kivity<avi@redhat.com>  wrote:
>
>    
>> On 09/19/2009 09:40 AM, Avi Kivity wrote:
>>      
>>> Add a general per-cpu notifier that is called whenever the kernel is
>>> about to return to userspace.  The notifier uses a thread_info flag
>>> and existing checks, so there is no impact on user return or context
>>> switch fast paths.
>>>
>>>        
>> Ingo/Peter?
>>      
> Would be nice to convert some existing open-coded return-to-user-space
> logic to this facility. One such candidate would be lockdep_sys_exit?
>    

I only implemented this for x86, while lockdep is arch independent.  If 
arch support is added, it should be trivial.

I think perf counters could use preempt notifiers though, these are arch 
independent.

-- 
error compiling committee.c: too many arguments to function

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