Wanpeng Li 8ca225520e x86/apic: Prevent tracing on apic_msr_write_eoi() ... The following RCU lockdep warning led to adding irq_enter()/irq_exit() into smp_reschedule_interrupt(): 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. do_trace_write_msr native_write_msr native_apic_msr_eoi_write smp_reschedule_interrupt reschedule_interrupt As Peterz pointed out: | So now we're making a very frequent interrupt slower because of debug | code. | | The thing is, many many smp_reschedule_interrupt() invocations don't | actually execute anything much at all and are only sent 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. Use the wrmsr_notrace() variant in native_apic_msr_write_eoi, annotate the kvm variant with notrace and add a native_apic_eoi callback to the apic structure so KVM guests are covered as well. This allows to revert the irq_enter/irq_exit dance in smp_reschedule_interrupt(). Suggested-by: Peter Zijlstra <peterz@infradead.org> Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Cc: kvm@vger.kernel.org Cc: Mike Galbraith <efault@gmx.de> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/1478488420-5982-3-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>		2016-11-09 22:03:14 +01:00
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asm	x86/apic: Prevent tracing on apic_msr_write_eoi()	2016-11-09 22:03:14 +01:00
uapi/asm	Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2016-10-03 17:29:01 -07:00