Re: [PATCH v7 1/7] sched/topology: Adding function partition_sched_domains_locked()

From: Juri Lelli
Date: Fri Apr 05 2019 - 08:52:59 EST


Hi,

On 05/04/19 14:04, Peter Zijlstra wrote:
> On Wed, Apr 03, 2019 at 10:46:44AM +0200, Juri Lelli wrote:
> > +/*
> > + * Call with hotplug lock held
>
> Is that spelled like:
>
> lockdep_assert_cpus_held();
>
> ?

Indeed, but I had that in previous versions and we removed that in v5
because it can lead to false positives [1,2]. IIRC, problem has to do
with hotplug and the fact that rebuilding from hotplug runs the
callbacks on the newly onlined CPU, not the task that acquired the lock.

Best,

- Juri

1 - https://lore.kernel.org/lkml/20180903142801.20046-1-juri.lelli@xxxxxxxxxx/
2 - https://lore.kernel.org/lkml/20180613121711.5018-2-juri.lelli@xxxxxxxxxx/