lkml.org 
[lkml]   [2011]   [Mar]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [RFC PATCH V4 5/5] cpuidle: cpuidle driver for apm
    Hi Stephen,

    Thanks for reviewing.

    On 03/23/2011 06:44 AM, Stephen Rothwell wrote:
    > Hi,
    >
    > On Tue, 22 Mar 2011 18:03:40 +0530 Trinabh Gupta<trinabh@linux.vnet.ibm.com> wrote:
    >>
    >> +static int apm_setup_cpuidle(int cpu)
    >> +{
    >> + struct cpuidle_device *dev = kzalloc(sizeof(struct cpuidle_device),
    >> + GFP_KERNEL);
    >
    > Same as xen comments: no NULL check.
    >
    >> + int count = CPUIDLE_DRIVER_STATE_START;
    >> + dev->cpu = cpu;
    >> + dev->drv =&apm_idle_driver;
    >
    > Also wondering why you would ever have a different idle routine on
    > different cpus?

    Yes, this is an ongoing debate. Apparently it is a possibility
    because of ACPI bugs. CPU's can have asymmetric C-states
    and overall different idle routines on different cpus. Please
    refer to http://lkml.org/lkml/2009/9/24/132 and
    https://lkml.org/lkml/2011/2/10/37 for a discussion around this.

    I have posted a patch series that does global registration
    i.e same idle routines for each cpu. Please check
    http://lkml.org/lkml/2011/3/22/161 . That series applies on
    top of this series. Global registration significantly
    simplifies the design, but still we are not sure about the
    direction to take.

    >
    >> +
    >> + dev->states[count] = state_apm_idle;
    >> + count++;
    >> +
    >> + dev->state_count = count;
    >> +
    >> + if (cpuidle_register_device(dev))
    >> + return -EIO;
    >
    > And we leak dev.
    >
    >> +static void apm_idle_exit(void)
    >> +{
    >> + cpuidle_unregister_driver(&apm_idle_driver);
    >
    > Do we leak the per cpu device structure here?

    I will see how we can save
    per cpu device structure pointers so that we can free them.

    >
    >> + return;
    >
    > Unnecessary return statement.
    >

    Thanks,
    -Trinabh


    \
     
     \ /
      Last update: 2011-03-23 11:27    [W:0.024 / U:90.244 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site