Messages in this thread |  | | From | Wanpeng Li <> | Subject | [PATCH v7 0/2] x86/apic: x2apic write eoi msr notrace | Date | Mon, 31 Oct 2016 09:37:00 +0800 |
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| RCU used illegally from idle CPU! | rcu_scheduler_active = 1, debug_locks = 0 | RCU used illegally from extended quiescent state! | no locks held by swapper/1/0. | | [<ffffffff9d492b95>] do_trace_write_msr+0x135/0x140 | [<ffffffff9d06f860>] native_write_msr+0x20/0x30 | [<ffffffff9d065fad>] native_apic_msr_eoi_write+0x1d/0x30 | [<ffffffff9d05bd1d>] smp_reschedule_interrupt+0x1d/0x30 | [<ffffffff9d8daec6>] reschedule_interrupt+0x96/0xa0
Reschedule interrupt may be called in cpu idle state. This causes lockdep check warning above.
As Peterz pointed out:
| The thing is, many many smp_reschedule_interrupt() invocations don't | actually execute anything much at all and are only send to tickle the | return to user path (which does the actual preemption). | | Having to do the whole irq_enter/irq_exit dance just for this unlikely | debug case totally blows.
This patchset adds x2apic write eoi msr notrace to avoid the debug codes splash and reverts irq_enter/irq_exit dance to avoid to make a very frequent interrupt slower because of debug code.
v6 -> v7: * cleanup storage class should be at the beginning of the declaration
v5 -> v6: * split the patch * don't duplicate the inline asm
v4 -> v5: * add notrace mark
v3 -> v4: * add notrace mark
v2 -> v3: * revert irq_enter/irq_exit() since it is merged
v1 -> v2: * add write msr notrace to avoid debug codes splash instead of slowdown a very frequent interrupt
Wanpeng Li (2): x86/msr: Add write msr notrace x86/apic: x2apic write eoi msr notrace
arch/x86/include/asm/apic.h | 3 ++- arch/x86/include/asm/msr.h | 14 +++++++++++++- arch/x86/kernel/apic/apic.c | 1 + arch/x86/kernel/kvm.c | 4 ++-- arch/x86/kernel/smp.c | 2 -- 5 files changed, 18 insertions(+), 6 deletions(-)
-- 1.9.1
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