Messages in this thread | | | Subject | Re: WARNING: cpu_is_offline() at native_smp_send_reschedule() | From | Peter Zijlstra <> | Date | Wed, 05 Sep 2012 12:54:40 +0200 |
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On Wed, 2012-09-05 at 12:35 +0800, Michael Wang wrote: > > [ 10.968565] reboot: machine restart > > [ 10.983510] ------------[ cut here ]------------ > > [ 10.984218] WARNING: at /c/kernel-tests/src/stable/arch/x86/kernel/smp.c:123 native_smp_send_reschedule+0x46/0x50() > > [ 10.985880] Pid: 88, comm: kpktgend_0 Not tainted 3.6.0-rc3-00005-gb374aa1 #10 > > [ 10.987185] Call Trace: > > [ 10.987506] [<7902f42a>] warn_slowpath_common+0x5a/0x80 > > [ 10.987506] [<7901ee16>] ? native_smp_send_reschedule+0x46/0x50 > > [ 10.987506] [<7901ee16>] ? native_smp_send_reschedule+0x46/0x50 > > [ 10.987506] [<7902f4fd>] warn_slowpath_null+0x1d/0x20 > > [ 10.987506] [<7901ee16>] native_smp_send_reschedule+0x46/0x50 > > So this cpu try to fire a nohz balance kick ipi to an offline cpu? > > May be we are choosing a wrong cpu to kick but that's not the point, > what I can't understand is why this cpu could do this kick. > > We have nohz_kick_needed() to check whether current cpu should do kick , > and the first condition we need to match is that current cpu should be > idle, but the trace show current pid is 88 not 0. > > We should add Peter to cc list, may be he will be interested on what > happened.
> > [ 10.987506] [<7905fdad>] trigger_load_balance+0x1bd/0x250 > > [ 10.987506] [<79056d14>] scheduler_tick+0xd4/0x100 > > [ 10.987506] [<7903bde5>] update_process_times+0x55/0x70
Hmm, added both venki and suresh as they touched it last ;-)
I suppose you're running a hotplug loop along with your workload?
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