lkml.org 
[lkml]   [2008]   [Aug]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: patch "x86: MOVE PCI IO ECS code to x86/pci" breaks CPU hotplug
    On 21.08.08 15:02:59, Ingo Molnar wrote:
    >
    > * Jan Beulich <jbeulich@novell.com> wrote:
    >
    > > Converting __cpuinit functions called out of init_amd() (and similar
    > > others) to __init (and making them subject of xxx_initcall() handling
    > > isn't valid, as they would no longer be called for hot plugged CPUs.
    > >
    > > Further, since it's likely that in virtualized environments the MSR
    > > write would at best be ignored, I'd also recommend using the
    > > fault-safe accessors here *and* check that the bit actually got set
    > > before setting PCI_HAS_IO_ECS (one would obviously have to BUG() when
    > > hot-plugged CPUs fail to set the bit when those available at boot
    > > successfully did so).
    >
    > hm, which patch is this exactly, and in what tree? It's not upstream nor
    > in -tip.

    Probably this in the mainline kernel is meant:

    commit 3a27dd1ce5de08e21e0266ddf00e6f1f843bfe8b
    Author: Robert Richter <robert.richter@amd.com>
    Date: Thu Jun 12 20:19:23 2008 +0200

    x86: Move PCI IO ECS code to x86/pci

    "Form follows function". Code is now where it belongs to.

    Signed-off-by: Robert Richter <robert.richter@amd.com>
    Signed-off-by: Ingo Molnar <mingo@elte.hu>

    The problem is code like this:

    +static int __init enable_pci_io_ecs(void)
    +{
    + /* assume all cpus from fam10h have IO ECS */
    + if (boot_cpu_data.x86 < 0x10)
    + return 0;
    + on_each_cpu(enable_pci_io_ecs_per_cpu, NULL, 1, 1);
    + pci_probe |= PCI_HAS_IO_ECS;
    + return 0;
    +}

    It is only called during the setup and if the cpu is enabled. I intend
    to rewrite the cpu setup code using cpu notifiers.

    -Robert

    --
    Advanced Micro Devices, Inc.
    Operating System Research Center
    email: robert.richter@amd.com



    \
     
     \ /
      Last update: 2008-08-21 15:19    [W:9.056 / U:0.036 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site