x86/UV2: Ack BAU interrupt earlier

This patch moves the ack of the BAU interrupt to the beginning
of  the interrupt handler so that there is less possibility of a
lost interrupt and slower response to a shootdown message.

Signed-off-by: Cliff Wickman <cpw@sgi.com>
Link: http://lkml.kernel.org/r/20120116212146.GE5767@sgi.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
index affea50..4686bf1 100644 (file)
--- a/arch/x86/platform/uv/tlb_uv.c
+++ b/arch/x86/platform/uv/tlb_uv.c
@@ -1218,6 +1218,7 @@ void uv_bau_message_interrupt(struct pt_regs *regs)
        struct ptc_stats *stat;
        struct msg_desc msgdesc;
 
+       ack_APIC_irq();
        time_start = get_cycles();
 
        bcp = &per_cpu(bau_control, smp_processor_id());
@@ -1247,8 +1248,6 @@ void uv_bau_message_interrupt(struct pt_regs *regs)
                stat->d_nomsg++;
        else if (count > 1)
                stat->d_multmsg++;
-
-       ack_APIC_irq();
 }
 
 /*