Messages in this thread | | | From | Lin Ming <> | Subject | | Date | Sun, 15 Apr 2012 14:09:30 +0800 |
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Hi all,
These 2 patches try to fix the "perf top" soft lockups under Xen reported by Steven at: https://lkml.org/lkml/2012/2/9/506
I tested it with 3.4-rc2 and "perf top" works well now.
Steven, Could you please help to test it too?
The soft lockup code path is:
__irq_work_queue arch_irq_work_raise apic->send_IPI_self(IRQ_WORK_VECTOR); apic_send_IPI_self __default_send_IPI_shortcut __xapic_wait_icr_idle
static inline void __xapic_wait_icr_idle(void) { while (native_apic_mem_read(APIC_ICR) & APIC_ICR_BUSY) cpu_relax(); }
The lockup happens at above while looop. The cause is that Xen has not implemented the APIC IPI interface yet. Xen has IPI interface: xen_send_IPI_one, but it's only used in xen_smp_send_reschedule, xen_smp_send_call_function_ipi and xen_smp_send_call_function_single_ipi, etc.
So we need to implement Xen's APIC IPI interface as Ben's patch does. And implement Xen's IRQ_WORK_VECTOR handler.
Ben Guthro (1): xen: implement apic ipi interface
Lin Ming (1): xen: implement IRQ_WORK_VECTOR handler
arch/x86/include/asm/xen/events.h | 1 + arch/x86/xen/enlighten.c | 7 ++ arch/x86/xen/smp.c | 111 +++++++++++++++++++++++++++++++++++- arch/x86/xen/smp.h | 12 ++++ 4 files changed, 127 insertions(+), 4 deletions(-)
Any comment is appreciated. Lin Ming
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