Message-ID: <4DC8E7C2.5080402@jp.fujitsu.com>
Date: Tue, 10 May 2011 16:22:42 +0900
From: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
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To: Paul Turner <pjt@google.com>
CC: linux-kernel@vger.kernel.org, Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Bharata B Rao <bharata@linux.vnet.ibm.com>,
        Dhaval Giani <dhaval.giani@gmail.com>,
        Balbir Singh <balbir@linux.vnet.ibm.com>,
        Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>,
        Srivatsa Vaddagiri <vatsa@in.ibm.com>,
        Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>,
        Ingo Molnar <mingo@elte.hu>, Pavel Emelyanov <xemul@openvz.org>
Subject: Re: [patch 07/15] sched: expire invalid runtime
References: <20110503092846.022272244@google.com> <20110503092905.075386331@google.com>
In-Reply-To: <20110503092905.075386331@google.com>
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(2011/05/03 18:28), Paul Turner wrote:
> With the global quota pool, one challenge is determining when the runtime we
> have received from it is still valid.  Fortunately we can take advantage of
> sched_clock synchronization around the jiffy to do this cheaply.
> 
> The one catch is that we don't know whether our local clock is behind or ahead
> of the cpu setting the expiration time (relative to its own clock).
> 
> Fortunately we can detect which of these is the case by determining whether the
> global deadline has advanced.  If it has not, then we assume we are behind, and
> advance our local expiration; otherwise, we know the deadline has truly passed
> and we expire our local runtime.
> 
> Signed-off-by: Paul Turner <pjt@google.com>
> 
> ---

Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>


Thanks,
H.Seto

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