From mboxrd@z Thu Jan  1 00:00:00 1970
From: Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH 1/3] perf: add context field to perf_event
Date: Tue, 12 Jul 2011 11:48:22 +0200
Message-ID: <20110712094822.GB29812@8bytes.org>
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Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Will Deacon <will.deacon@arm.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	Ingo Molnar <mingo@elte.hu>,
	"acme@ghostprotocols.net" <acme@ghostprotocols.net>,
	Jason Wessel <jason.wessel@windriver.com>
To: Avi Kivity <avi@redhat.com>
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On Tue, Jul 12, 2011 at 12:44:17PM +0300, Avi Kivity wrote:
> On 07/12/2011 12:41 PM, Joerg Roedel wrote:
>> >  Using TIF_bits sounds like a much better solution for this, wakeups are
>> >  really rather expensive and its best to avoid extra if at all possible.
>>
>> I would rather vote for Avi's solution too. Such a functionality is very
>> helpful for LWP-perf integration as well (because we need a way to call
>> do_mmap for a task != current).
>>
>
> It's not needed for that.  See use_mm() (caller must be a kernel thread).

But in our case the caller would be the process that wants to count, not
a kernel thread.

	Joerg