Messages in this thread | | | Subject | Re: 4.5.0+ panic when setup loop device | From | Mike Galbraith <> | Date | Fri, 18 Mar 2016 13:39:16 +0100 |
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On Fri, 2016-03-18 at 11:15 +0100, Peter Zijlstra wrote: > On Fri, Mar 18, 2016 at 05:11:54AM +0100, Mike Galbraith wrote: > > On Thu, 2016-03-17 at 10:52 +0100, Peter Zijlstra wrote: > > > > > Andreas; Borislav said to Cc you since you wrote all this. > > > The issue is that Linux assumes: > > > > > > > nr_logical_cpus = nr_cores * nr_siblings > > > > It also seems to now assume that if SMT is possible, it's enabled. > > > > Below is my 8 socket DL980 G7, which has SMT turned off for RT > > testing, > > booting NOPREEMPT master tuned for maximum bloat ala distro and > > getting > > confused by me telling it (as always) nr_cpus=64. Bad juju ensues. > > Ah, did you actually disable HT in the BIOS, or just skip the HT > enumeration by saying nr_cpus=64 (knowing that all the siblings are > last)?
It's disabled in BIOS.
> In any case, Thomas has a clue and I'm going to test, but 4 socket > machine takes forever to boot, so might be a few minutes :/
His one-liner made my DL980 all better.
-Mike
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