| Date | Fri, 6 Mar 2020 17:03:42 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 08/12] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() |
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On Wed, Mar 04, 2020 at 04:12:40PM +0000, Alex Belits wrote: > From: Yuri Norov <ynorov@marvell.com> > > For nohz_full CPUs the desirable behavior is to receive interrupts > generated by tick_nohz_full_kick_cpu(). But for hard isolation it's > obviously not desirable because it breaks isolation. > > This patch adds check for it. > > Signed-off-by: Alex Belits <abelits@marvell.com> > --- > kernel/time/tick-sched.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index 1d4dec9d3ee7..fe4503ba1316 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -20,6 +20,7 @@ > #include <linux/sched/clock.h> > #include <linux/sched/stat.h> > #include <linux/sched/nohz.h> > +#include <linux/isolation.h> > #include <linux/module.h> > #include <linux/irq_work.h> > #include <linux/posix-timers.h> > @@ -262,7 +263,7 @@ static void tick_nohz_full_kick(void) > */ > void tick_nohz_full_kick_cpu(int cpu) > { > - if (!tick_nohz_full_cpu(cpu)) > + if (!tick_nohz_full_cpu(cpu) || task_isolation_on_cpu(cpu)) > return;
I fear you can't do that. A nohz full CPU is kicked for a reason. As for the other cases, you need to fix the callers.
In the general case, randomly ignoring an interrupt is a correctness issue.
Thanks.
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