Re: kvm_intel: Could not allocate 42 bytes percpu data

[Chegu Vinod]

On 7/1/2013 10:49 PM, Rusty Russell wrote:
> Chegu Vinod <chegu_vinod@xxxxxx> writes:
> > On 6/30/2013 11:22 PM, Rusty Russell wrote:
> > > Chegu Vinod <chegu_vinod@xxxxxx> writes:
> > > > Hello,
> > > >
> > > > Lots (~700+) of the following messages are showing up in the dmesg of a
> > > > 3.10-rc1 based kernel (Host OS is running on a large socket count box
> > > > with HT-on).
> > > >
> > > > [   82.270682] PERCPU: allocation failed, size=42 align=16, alloc from
> > > > reserved chunk failed
> > > > [   82.272633] kvm_intel: Could not allocate 42 bytes percpu data
> > > Woah, weird....
> > >
> > > Oh.  Shit.  Um, this is embarrassing.
> > >
> > > Thanks,
> > > Rusty.
> >
> > Thanks for your response!
> >
> > > ===
> > > module: do percpu allocation after uniqueness check.  No, really!
> > >
> > > v3.8-rc1-5-g1fb9341 was supposed to stop parallel kvm loads exhausting
> > > percpu memory on large machines:
> > >
> > >       Now we have a new state MODULE_STATE_UNFORMED, we can insert the
> > >       module into the list (and thus guarantee its uniqueness) before we
> > >       allocate the per-cpu region.
> > >
> > > In my defence, it didn't actually say the patch did this.  Just that
> > > we "can".
> > >
> > > This patch actually *does* it.
> > >
> > > Signed-off-by: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
> > > Tested-by: Noone it seems.
> > Your following "updated" fix seems to be working fine on the larger
> > socket count machine with HT-on.
> OK, did you definitely revert every other workaround?

Yes no other workarounds were there when your change was tested.

> If so, please give me a Tested-by: line...

FYI.... The actual verification of your change was done by my esteemed 
colleague :Jim Hull (cc'd) who had access to this larger socket count box.



Tested-by: Jim Hull <jim.hull@xxxxxx>




Thanks
Vinod


> Thanks,
> Rusty.
> .

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