[firefly] [PATCH] rcu: Notice if an all-zero cpumask is set inside a critical section

Iulia Manda iulia.manda21 at gmail.com
Mon Mar 17 14:19:15 EET 2014


On 17 March 2014 14:12, Daniel Baluta <daniel.baluta at gmail.com> wrote:

> On Mon, Mar 17, 2014 at 1:53 PM, Iulia Manda <iulia.manda21 at gmail.com>
> wrote:
> > In torture_shuffle_tasks function, the check if an all-zero mask can
> > be passed to set_cpus_allowed_ptr() is redundant after clearing the
> > shuffle_idle_cpu bit. If the mask had more than one bit set, after
> > clearing a bit it has at least one bit set. If the mask had only
> > one bit set, a check is made at the beginning, where the function
> > returns, as there is no need to shuffle only one cpu.
> >
> > Also, this code is executed inside a critical section, delimited by
> > get_online_cpus() and put_online_cpus(), preventing CPUs from leaving
> between
> > the check of num_online_cpus and the calls to set_cpus_allowed_ptr().
>
> Is this a kernel patch? If yes, which tree?
>
> I can't find kernel/torture.c in linux/ tree. There is only
> kernel/rcu/torture.c.
>
> thanks,
> Daniel.
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>


It is a patch for -rcu tree (git://
git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git),
on branch rcu/dev.

Thanks,
Iulia M.
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