rcu stalls seen with numasched_v2 patches applied.

From: Srikar Dronamraju
Date: Tue Aug 07 2012 - 08:34:22 EST


Hi,

I saw this while I was running the 2nd August -tip kernel + Peter's
numasched patches.

Top showed load average to be 240, there was one cpu (cpu 7) which
showed 100% while all other cpus were idle. The system showed some
sluggishness. Before I saw this I ran Andrea's autonuma benchmark couple
of times.

I am not sure if this is an already reported issue/known issue.

INFO: rcu_sched self-detected stall on CPU { 7} (t=105182911 jiffies)
Pid: 5173, comm: qpidd Tainted: G W 3.5.0numasched_v2_020812+ #1
Call Trace:
<IRQ> [<ffffffff810d4c7e>] rcu_check_callbacks+0x18e/0x650
[<ffffffff81060918>] update_process_times+0x48/0x90
[<ffffffff810a2a7e>] tick_sched_timer+0x6e/0xe0
[<ffffffff810789a5>] __run_hrtimer+0x75/0x1a0
[<ffffffff810a2a10>] ? tick_setup_sched_timer+0x100/0x100
[<ffffffff810591cf>] ? __do_softirq+0x13f/0x240
[<ffffffff81078d56>] hrtimer_interrupt+0xf6/0x240
[<ffffffff814f0179>] smp_apic_timer_interrupt+0x69/0x99
[<ffffffff814ef14a>] apic_timer_interrupt+0x6a/0x70
<EOI> [<ffffffff814e64b2>] ? _raw_spin_unlock_irqrestore+0x12/0x20
[<ffffffff81082552>] sched_setnode+0x82/0xf0
[<ffffffff8108bd38>] task_numa_work+0x1e8/0x240
[<ffffffff81070c6c>] task_work_run+0x6c/0x80
[<ffffffff81013984>] do_notify_resume+0x94/0xa0
[<ffffffff814e6a6c>] retint_signal+0x48/0x8c
INFO: rcu_sched self-detected stall on CPU { 7} (t=105362914 jiffies)
Pid: 5173, comm: qpidd Tainted: G W 3.5.0numasched_v2_020812+ #1
Call Trace:
<IRQ> [<ffffffff810d4c7e>] rcu_check_callbacks+0x18e/0x650
[<ffffffff81060918>] update_process_times+0x48/0x90
[<ffffffff810a2a7e>] tick_sched_timer+0x6e/0xe0
[<ffffffff810789a5>] __run_hrtimer+0x75/0x1a0
[<ffffffff810a2a10>] ? tick_setup_sched_timer+0x100/0x100
[<ffffffff810591cf>] ? __do_softirq+0x13f/0x240
[<ffffffff81078d56>] hrtimer_interrupt+0xf6/0x240
[<ffffffff814f0179>] smp_apic_timer_interrupt+0x69/0x99
[<ffffffff814ef14a>] apic_timer_interrupt+0x6a/0x70
<EOI> [<ffffffff81082562>] ? sched_setnode+0x92/0xf0
[<ffffffff81082552>] ? sched_setnode+0x82/0xf0
[<ffffffff8108bd38>] task_numa_work+0x1e8/0x240
[<ffffffff81070c6c>] task_work_run+0x6c/0x80
[<ffffffff81013984>] do_notify_resume+0x94/0xa0
[<ffffffff814e6a6c>] retint_signal+0x48/0x8c
INFO: rcu_sched self-detected stall on CPU { 7} (t=105542917 jiffies)
Pid: 5173, comm: qpidd Tainted: G W 3.5.0numasched_v2_020812+ #1
Call Trace:
<IRQ> [<ffffffff810d4c7e>] rcu_check_callbacks+0x18e/0x650
[<ffffffff81060918>] update_process_times+0x48/0x90
[<ffffffff810a2a7e>] tick_sched_timer+0x6e/0xe0
[<ffffffff810789a5>] __run_hrtimer+0x75/0x1a0
[<ffffffff810a2a10>] ? tick_setup_sched_timer+0x100/0x100
[<ffffffff810591cf>] ? __do_softirq+0x13f/0x240
[<ffffffff81078d56>] hrtimer_interrupt+0xf6/0x240
[<ffffffff814f0179>] smp_apic_timer_interrupt+0x69/0x99
[<ffffffff814ef14a>] apic_timer_interrupt+0x6a/0x70
<EOI> [<ffffffff814e64b2>] ? _raw_spin_unlock_irqrestore+0x12/0x20
[<ffffffff81082552>] sched_setnode+0x82/0xf0
[<ffffffff8108bd38>] task_numa_work+0x1e8/0x240
[<ffffffff81070c6c>] task_work_run+0x6c/0x80
[<ffffffff81013984>] do_notify_resume+0x94/0xa0
[<ffffffff814e6a6c>] retint_signal+0x48/0x8c


<these messages keep repeating>

I saw this on a 2 node 24 cpu machine.

If I am able to reproduce this again, I plan to test these without the
numasched patches applied.

--
Thanks and Regards
Srikar Dronamraju

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