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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] IRQ: Group IRQ_MOVE_CLEANUP_VECTOR with other hypervisor IPIs
On 08/09/2011 08:39, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
>>>> On 07.09.11 at 18:56, Keir Fraser <keir.xen@xxxxxxxxx> wrote:
>> On 07/09/2011 17:03, "Jan Beulich" <JBeulich@xxxxxxxx> wrote:
>>
>>>>>> On 07.09.11 at 17:03, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
>>>
>>> Are you sure this is correct? I'm suspicious that this may intentionally
>>> have been the lowest priority vector...
>>
>> I can't see why?
>
> Perhaps to get all "real" interrupts serviced first, and then do a single,
> consolidated run through everything that needs cleaning up? All the
> more since smp_irq_move_cleanup_interrupt() may re-issue the
> interrupt to the local CPU.
Ah, hm, that's a good point. We obviously livelock if we make
IRQ_MOVE_CLEANUP_VECTOR higher priority than the vector that
smp_irq_move_cleanup_interrupt() is attempting to retry.
Andrew: I think we have to leave this vector where it is, but you could add
a comment explaining why it is so, in your cleanup patchset.
-- Keir
> Cc-ing the original author in the hope that
> he's still at Intel.
>
> And btw., if that change is correct, then the setting of
> bit IRQ_MOVE_CLEANUP_VECTOR in used_vectors should actually be
> removed - while used_vectors currently is dimensioned as NR_VECTORS,
> none of the other "special" vectors get their bits set there, and the bit
> array could therefore easily be shrunk to just NR_DYNAMIC_VECTORS.
>
> Jan
>
>>>> Also, rename to MOVE_CLEANUP_VECTOR to be in line with the other IPI
>>>> names.
>>>
>>> Why would the removal of part of the descriptive name be in line with
>>> the other names? We're dealing with the cleanup after an IRQ move
>>> here, so let the name state this. The IRQ_ prefix here has nothing to
>>> do with this being the vector for a specific IRQ.
>>
>> Agreed.
>>
>> -- Keir
>>
>>> Jan
>>>
>>>> This requires bumping LAST_HIPRIORITY_VECTOR, but does mean that the
>>>> range FIRST-LAST_HIPRIORITY_VECTORs are free once again.
>>>>
>>>> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>>>>
>>>> diff -r 0268e7380953 -r c7884dbb6f7d xen/arch/x86/apic.c
>>>> --- a/xen/arch/x86/apic.c Mon Sep 05 15:10:28 2011 +0100
>>>> +++ b/xen/arch/x86/apic.c Wed Sep 07 16:00:55 2011 +0100
>>>> @@ -90,7 +90,7 @@ bool_t __read_mostly directed_eoi_enable
>>>> * through the ICC by us (IPIs)
>>>> */
>>>> __asm__(".section .text");
>>>> -BUILD_SMP_INTERRUPT(irq_move_cleanup_interrupt,IRQ_MOVE_CLEANUP_VECTOR)
>>>> +BUILD_SMP_INTERRUPT(irq_move_cleanup_interrupt,MOVE_CLEANUP_VECTOR)
>>>> BUILD_SMP_INTERRUPT(event_check_interrupt,EVENT_CHECK_VECTOR)
>>>> BUILD_SMP_INTERRUPT(invalidate_interrupt,INVALIDATE_TLB_VECTOR)
>>>> BUILD_SMP_INTERRUPT(call_function_interrupt,CALL_FUNCTION_VECTOR)
>>>> diff -r 0268e7380953 -r c7884dbb6f7d xen/arch/x86/hvm/vmx/vmx.c
>>>> --- a/xen/arch/x86/hvm/vmx/vmx.c Mon Sep 05 15:10:28 2011 +0100
>>>> +++ b/xen/arch/x86/hvm/vmx/vmx.c Wed Sep 07 16:00:55 2011 +0100
>>>> @@ -1986,7 +1986,7 @@ static void vmx_do_extint(struct cpu_use
>>>>
>>>> switch ( vector )
>>>> {
>>>> - case IRQ_MOVE_CLEANUP_VECTOR:
>>>> + case MOVE_CLEANUP_VECTOR:
>>>> smp_irq_move_cleanup_interrupt(regs);
>>>> break;
>>>> case LOCAL_TIMER_VECTOR:
>>>> diff -r 0268e7380953 -r c7884dbb6f7d xen/arch/x86/io_apic.c
>>>> --- a/xen/arch/x86/io_apic.c Mon Sep 05 15:10:28 2011 +0100
>>>> +++ b/xen/arch/x86/io_apic.c Wed Sep 07 16:00:55 2011 +0100
>>>> @@ -476,7 +476,7 @@ fastcall void smp_irq_move_cleanup_inter
>>>> * to myself.
>>>> */
>>>> if (irr & (1 << (vector % 32))) {
>>>> - genapic->send_IPI_self(IRQ_MOVE_CLEANUP_VECTOR);
>>>> + genapic->send_IPI_self(MOVE_CLEANUP_VECTOR);
>>>> TRACE_3D(TRC_HW_IRQ_MOVE_CLEANUP_DELAY,
>>>> irq, vector, smp_processor_id());
>>>> goto unlock;
>>>> @@ -513,7 +513,7 @@ static void send_cleanup_vector(struct i
>>>>
>>>> cpus_and(cleanup_mask, cfg->old_cpu_mask, cpu_online_map);
>>>> cfg->move_cleanup_count = cpus_weight(cleanup_mask);
>>>> - genapic->send_IPI_mask(&cleanup_mask, IRQ_MOVE_CLEANUP_VECTOR);
>>>> + genapic->send_IPI_mask(&cleanup_mask, MOVE_CLEANUP_VECTOR);
>>>>
>>>> cfg->move_in_progress = 0;
>>>> }
>>>> diff -r 0268e7380953 -r c7884dbb6f7d xen/arch/x86/irq.c
>>>> --- a/xen/arch/x86/irq.c Mon Sep 05 15:10:28 2011 +0100
>>>> +++ b/xen/arch/x86/irq.c Wed Sep 07 16:00:55 2011 +0100
>>>> @@ -338,7 +338,7 @@ int __init init_irq_data(void)
>>>> set_bit(HYPERCALL_VECTOR, used_vectors);
>>>>
>>>> /* IRQ_MOVE_CLEANUP_VECTOR used for clean up vectors */
>>>> - set_bit(IRQ_MOVE_CLEANUP_VECTOR, used_vectors);
>>>> + set_bit(MOVE_CLEANUP_VECTOR, used_vectors);
>>>>
>>>> return 0;
>>>> }
>>>> diff -r 0268e7380953 -r c7884dbb6f7d xen/arch/x86/smpboot.c
>>>> --- a/xen/arch/x86/smpboot.c Mon Sep 05 15:10:28 2011 +0100
>>>> +++ b/xen/arch/x86/smpboot.c Wed Sep 07 16:00:55 2011 +0100
>>>> @@ -1027,7 +1027,7 @@ void __init smp_intr_init(void)
>>>> }
>>>>
>>>> /* IPI for cleanuping vectors after irq move */
>>>> - set_intr_gate(IRQ_MOVE_CLEANUP_VECTOR, irq_move_cleanup_interrupt);
>>>> + set_intr_gate(MOVE_CLEANUP_VECTOR, irq_move_cleanup_interrupt);
>>>>
>>>> /* IPI for event checking. */
>>>> set_intr_gate(EVENT_CHECK_VECTOR, event_check_interrupt);
>>>> diff -r 0268e7380953 -r c7884dbb6f7d
>>>> xen/include/asm-x86/mach-default/irq_vectors.h
>>>> --- a/xen/include/asm-x86/mach-default/irq_vectors.h Mon Sep 05 15:10:28
>>>> 2011
>>>> +0100
>>>> +++ b/xen/include/asm-x86/mach-default/irq_vectors.h Wed Sep 07 16:00:55
>>>> 2011
>>>> +0100
>>>> @@ -11,12 +11,14 @@
>>>> #define LOCAL_TIMER_VECTOR 0xf9
>>>> #define PMU_APIC_VECTOR 0xf8
>>>> #define CMCI_APIC_VECTOR 0xf7
>>>> +#define MOVE_CLEANUP_VECTOR 0xf6
>>>> +
>>>> /*
>>>> * High-priority dynamically-allocated vectors. For interrupts that
>>>> * must be higher priority than any guest-bound interrupt.
>>>> */
>>>> #define FIRST_HIPRIORITY_VECTOR 0xf0
>>>> -#define LAST_HIPRIORITY_VECTOR 0xf6
>>>> +#define LAST_HIPRIORITY_VECTOR 0xf5
>>>>
>>>> /* Legacy PIC uses vectors 0xe0-0xef. */
>>>> #define FIRST_LEGACY_VECTOR 0xe0
>>>> @@ -30,8 +32,6 @@
>>>> #define LAST_DYNAMIC_VECTOR 0xdf
>>>> #define NR_DYNAMIC_VECTORS (LAST_DYNAMIC_VECTOR - FIRST_DYNAMIC_VECTOR +
>>>> 1)
>>>>
>>>> -#define IRQ_MOVE_CLEANUP_VECTOR FIRST_DYNAMIC_VECTOR
>>>> -
>>>> #define NR_VECTORS 256
>>>>
>>>> #endif /* _ASM_IRQ_VECTORS_H */
>>>>
>>>> _______________________________________________
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>>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>>> http://lists.xensource.com/xen-devel
>>>
>>>
>>>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>> http://lists.xensource.com/xen-devel
>
>
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