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Thu, 24 Sep 2020 08:40:33 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 4FD5C3007CD; Thu, 24 Sep 2020 10:40:30 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id E59382BC141EA; Thu, 24 Sep 2020 10:40:29 +0200 (CEST) Date: Thu, 24 Sep 2020 10:40:29 +0200 From: peterz@infradead.org To: Nitesh Narayan Lal Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, intel-wired-lan@lists.osuosl.org, frederic@kernel.org, mtosatti@redhat.com, sassmann@redhat.com, jesse.brandeburg@intel.com, lihong.yang@intel.com, helgaas@kernel.org, jeffrey.t.kirsher@intel.com, jacob.e.keller@intel.com, jlelli@redhat.com, hch@infradead.org, bhelgaas@google.com, mike.marciniszyn@intel.com, dennis.dalessandro@intel.com, thomas.lendacky@amd.com, jerinj@marvell.com, mathias.nyman@intel.com, jiri@nvidia.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org Subject: Re: [PATCH v2 1/4] sched/isolation: API to get housekeeping online CPUs Message-ID: <20200924084029.GC1362448@hirez.programming.kicks-ass.net> References: <20200923181126.223766-1-nitesh@redhat.com> <20200923181126.223766-2-nitesh@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200923181126.223766-2-nitesh@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > --- > 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.