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SubjectRe: [PATCH v2 1/4] sched/isolation: API to get housekeeping online CPUs
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On 9/24/20 8:09 AM, Frederic Weisbecker wrote:
> On Thu, Sep 24, 2020 at 10:40:29AM +0200, peterz@infradead.org wrote:
>> On Wed, Sep 23, 2020 at 02:11:23PM -0400, Nitesh Narayan Lal wrote:
>>> Introduce a new API hk_num_online_cpus(), that can be used to
>>> retrieve the number of online housekeeping CPUs that are meant to handle
>>> managed IRQ jobs.
>>>
>>> This API is introduced for the drivers that were previously relying only
>>> on num_online_cpus() to determine the number of MSIX vectors to create.
>>> In an RT environment with large isolated but fewer housekeeping CPUs this
>>> was leading to a situation where an attempt to move all of the vectors
>>> corresponding to isolated CPUs to housekeeping CPUs were failing due to
>>> per CPU vector limit.
>>>
>>> Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
>>> ---
>>> include/linux/sched/isolation.h | 13 +++++++++++++
>>> 1 file changed, 13 insertions(+)
>>>
>>> diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
>>> index cc9f393e2a70..2e96b626e02e 100644
>>> --- a/include/linux/sched/isolation.h
>>> +++ b/include/linux/sched/isolation.h
>>> @@ -57,4 +57,17 @@ static inline bool housekeeping_cpu(int cpu, enum hk_flags flags)
>>> return true;
>>> }
>>>
>>> +static inline unsigned int hk_num_online_cpus(void)
>> This breaks with the established naming of that header.
> I guess we can make it housekeeping_num_online_cpus() ?

Right, I can do that.

Thanks

>
--
Nitesh

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