On Tue, Sep 22, 2020 at 09:50:55AM -0400, Nitesh Narayan Lal wrote: > On 9/22/20 6:08 AM, Frederic Weisbecker wrote: > TBH I don't have a very strong case here at the moment. > But still, IMHO, this will force the user to have both managed irqs and > nohz_full in their environments to avoid these kinds of issues. Is that how > we would like to proceed? Yep that sounds good to me. I never know how much we want to split each and any of the isolation features but I'd rather stay cautious to separate HK_FLAG_TICK from the rest, just in case running in nohz_full mode ever becomes interesting alone for performance and not just latency/isolation. But look what you can do as well: diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 5a6ea03f9882..9df9598a9e39 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -141,7 +141,7 @@ static int __init housekeeping_nohz_full_setup(char *str) unsigned int flags; flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU | - HK_FLAG_MISC | HK_FLAG_KTHREAD; + HK_FLAG_MISC | HK_FLAG_KTHREAD | HK_FLAG_MANAGED_IRQ; return housekeeping_setup(str, flags); } "nohz_full=" has historically gathered most wanted isolation features. It can as well isolate managed irqs. > > And then can we rename it to housekeeping_num_online()? > > It could be just me, but does something like hk_num_online_cpus() makes more > sense here? Sure, that works as well. Thanks.
