From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nitesh Narayan Lal Date: Thu, 24 Sep 2020 08:26:18 -0400 Subject: [Intel-wired-lan] [PATCH v2 1/4] sched/isolation: API to get housekeeping online CPUs In-Reply-To: <20200924121150.GB19346@lenoir> References: <20200923181126.223766-1-nitesh@redhat.com> <20200923181126.223766-2-nitesh@redhat.com> <20200924121150.GB19346@lenoir> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: On 9/24/20 8:11 AM, Frederic Weisbecker 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 >> --- >> 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) >> +{ >> +#ifdef CONFIG_CPU_ISOLATION >> + const struct cpumask *hk_mask; >> + >> + if (static_branch_unlikely(&housekeeping_overridden)) { >> + hk_mask = housekeeping_cpumask(HK_FLAG_MANAGED_IRQ); > HK_FLAG_MANAGED_IRQ should be pass as an argument to the function: > > housekeeping_num_online_cpus(HK_FLAG_MANAGED_IRQ) because it's > completely arbitrary otherwise. Yeap that is more sensible, I will do that. Do you have any other concerns/suggestions on any other patch? > >> + return cpumask_weight(hk_mask); >> + } >> +#endif >> + return cpumask_weight(cpu_online_mask); >> +} >> + >> #endif /* _LINUX_SCHED_ISOLATION_H */ >> -- >> 2.18.2 >> -- Thanks Nitesh -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 833 bytes Desc: OpenPGP digital signature URL: