lkml.org 
[lkml]   [2008]   [Aug]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: Regression in 2.6.27-rc1 for set_cpus_allowed_ptr
    Date
    [Adding CCs]

    On Friday, 8 of August 2008, Langsdorf, Mark wrote:
    > One of my co-workers noticed that the powernow-k8
    > driver no longer restarts when a CPU core is
    > hot-disabled and then hot-enabled on AMD quad-core
    > systems.
    >
    > The following comands work fine on 2.6.26 and fail
    > on 2.6.27-rc1:
    >
    > echo 0 > /sys/devices/system/cpu/cpu3/online
    > echo 1 > /sys/devices/system/cpu/cpu3/online
    > find /sys -name cpufreq
    >
    > For 2.6.26, the find will return a cpufreq
    > directory for each processor. In 2.6.27-rc1,
    > the cpu3 directory is missing.
    >
    > After digging through the code, the following
    > logic is failing when the core is hot-enabled
    > at runtime. The code works during the boot
    > sequence.
    >
    > cpumask_t = current->cpus_allowed;
    > set_cpus_allowed_ptr(current, &cpumask_of_cpu(cpu));
    > if (smp_processor_id() != cpu)
    > return -ENODEV;
    >
    > The objective is to move to the specific CPU and
    > test it's MSRs to see if it is supported. For
    > some reason, it isn't working. Any suggestions
    > on how to fix this are appreciated.
    >
    > -Mark Langdsorf
    > Operating System Research Center
    > AMD


    \
     
     \ /
      Last update: 2008-08-08 23:03    [W:0.040 / U:29.580 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site