Messages in this thread | | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH v2 4/7] x86/hyper-v: redirect reenlightment notifications on CPU offlining | Date | Mon, 15 Jan 2018 11:44:12 +0100 |
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Thomas Gleixner <tglx@linutronix.de> writes:
> On Wed, 13 Dec 2017, Vitaly Kuznetsov wrote: >> +static int hv_cpu_die(unsigned int cpu) >> +{ >> + struct hv_reenlightenment_control re_ctrl; >> + int i; >> + static DEFINE_SPINLOCK(lock); >> + >> + if (hv_reenlightenment_cb == NULL) >> + return 0; >> + >> + /* Make sure the CPU we migrate to is not going away too */ >> + spin_lock(&lock); > > What kind of voodoo is this? CPU hotplug is serialized already... >
Yes, someone around made a comment 'what happens if some day we'll have parallel cpu hot[un]plug' and I added this. Not really needed, will drop in v3.
>> + rdmsrl(HV_X64_MSR_REENLIGHTENMENT_CONTROL, *((u64 *)&re_ctrl)); >> + if (re_ctrl.target_vp == hv_vp_index[cpu]) { >> + /* Find some other online CPU */ >> + for_each_online_cpu(i) { > > cpu = cpumask_any_but(cpu_online_mask); > > Hmm? >
Cool, thanks)
-- Vitaly
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