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    SubjectRe: [PATCH 2/5] stop_machine: yield CPU during stop machine
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    On 21/10/16 14:05, Peter Zijlstra wrote:
    > On Fri, Oct 21, 2016 at 01:58:55PM +0200, Christian Borntraeger wrote:
    >> stop_machine can take a very long time if the hypervisor does
    >> overcommitment for guest CPUs. When waiting for "the one", lets
    >> give up our CPU by using the new cpu_relax_yield.
    >
    > This seems something that would apply to most other virt stuff. Lets Cc
    > a few more lists for that.

    Corrected xen-devel mail address.


    Juergen

    >
    >> Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
    >> ---
    >> kernel/stop_machine.c | 2 +-
    >> 1 file changed, 1 insertion(+), 1 deletion(-)
    >>
    >> diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
    >> index ec9ab2f..1eb8266 100644
    >> --- a/kernel/stop_machine.c
    >> +++ b/kernel/stop_machine.c
    >> @@ -194,7 +194,7 @@ static int multi_cpu_stop(void *data)
    >> /* Simple state machine */
    >> do {
    >> /* Chill out and ensure we re-read multi_stop_state. */
    >> - cpu_relax();
    >> + cpu_relax_yield();
    >> if (msdata->state != curstate) {
    >> curstate = msdata->state;
    >> switch (curstate) {
    >> --
    >> 2.5.5
    >>
    > _______________________________________________
    > Virtualization mailing list
    > Virtualization@lists.linux-foundation.org
    > https://lists.linuxfoundation.org/mailman/listinfo/virtualization
    >

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