Messages in this thread |  | | Subject | Re: [PATCH 1/4] tick/sched: Forward timer even in nohz mode | From | Scott Wood <> | Date | Mon, 06 Jan 2020 14:12:19 -0600 |
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On Mon, 2019-12-16 at 18:22 -0500, Scott Wood wrote: > Currently when exiting nohz, the expiry will be forwarded as if we > had just run the timer. If we re-enter nohz before this new expiry, > and exit after, this forwarding will happen again. If this load pattern > recurs the tick can be indefinitely postponed. > > To avoid this, use last_tick as-is rather than calling hrtimer_forward(). > However, in some cases the tick *will* have just run (despite being > "stopped"), and leading to double timer execution. > > To avoid that, forward the timer after every tick (regardless of nohz > status) and keep last_tick up-to-date. During nohz, last_tick will > reflect what the expiry would have been if not in nohz mode. > > Signed-off-by: Scott Wood <swood@redhat.com> > --- > kernel/time/tick-sched.c | 11 +++++------ > 1 file changed, 5 insertions(+), 6 deletions(-)
Any comments on these patches?
Thanks, Scott
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