lkml.org 
[lkml]   [2011]   [Mar]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [Xen-devel] Re: [RFC PATCH V4 2/5] cpuidle: list based cpuidle driver registration and selection


    thanks,
    Len Brown, Intel Open Source Technology Center

    On Fri, 25 Mar 2011, Konrad Rzeszutek Wilk wrote:

    > On Fri, Mar 25, 2011 at 03:05:36AM -0400, Len Brown wrote:
    > > > I think there are other problems too, related to saving and restoring
    > > > of pm_idle pointer. For example, cpuidle itself saves current value
    > > > of pm_idle, flips it and then restores the saved value. There is
    > > > no guarantee that the saved function still exists. APM does exact
    > > > same thing (though it may not be used these days).
    > > >
    > > > The problem also is that a number of architectures have copied the
    > > > same design based on pm_idle; so its spreading.
    > >
    > > pm_idle is a primitive design yes, but I think the issue
    > > with pm_idle is a theoretical one, at least on x86;
    > > as there isn't any other code scribbling on pm_idle
    > > in practice. So this is clean-up, rather than bug-fix work...
    > >
    > > > > It isn't immediately clear to me that all of these options
    > > > > need to be preserved.
    > > >
    > > > So what do you suggest can be removed?
    > >
    > > I sent a series of small patches yesterday to get the ball rolling...
    > > https://lkml.org/lkml/2011/3/24/54
    > >
    > > I think the xen thing can go away.
    >
    > The xen thing being the setting of cpuidle to halt or the proposed
    > patch?

    I don't think Xen needs a cpuidle driver.
    Xen just needs to tell the kernel to call HALT,
    and I think we'll keep that around for the non-cpuidle case,
    and for the idle periods before cpuidle initializes.

    cheers,
    Len Brown, Intel Open Source Technology Center



    \
     
     \ /
      Last update: 2011-03-31 04:29    [W:0.022 / U:243.992 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site