Re: [PATCH] x86: Distinguish TLB shootdown interrupts from otherfunctions call interrupts

From: Alex Shi
Date: Thu Sep 27 2012 - 03:03:12 EST


>>

>> the 3.6 kernel will closed soon. it will be great to has this patch in.
>> So, could you like to refresh your patch with popular comments format? :)
>
> Fixed patch is below.
> Thank you for the review again.
>



Peter:

Maybe the patch doesn't looks perfect for this issue.
So I am wondering if the following patch is better, if we don't care the irq_tlb
was counted again in irq_call?

===
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 613cd83..2d6d8ed 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -98,6 +98,8 @@ static void flush_tlb_func(void *info)
{
struct flush_tlb_info *f = info;

+ inc_irq_stat(irq_tlb_count);
+
if (f->flush_mm != this_cpu_read(cpu_tlbstate.active_mm))
return;
===

Or another solution is also reducing double counted irq_tlb_count from irq_call_count
What's your comments of this?

===
diff --git a/arch/x86/include/asm/hardirq.h b/arch/x86/include/asm/hardirq.h
index d3895db..aac7886 100644
--- a/arch/x86/include/asm/hardirq.h
+++ b/arch/x86/include/asm/hardirq.h
@@ -36,6 +36,7 @@ DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
#define __ARCH_IRQ_STAT

#define inc_irq_stat(member) this_cpu_inc(irq_stat.member)
+#define dec_irq_stat(member) this_cpu_dec(irq_stat.member)

#define local_softirq_pending() this_cpu_read(irq_stat.__softirq_pending)

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 613cd83..b82bd9f 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -98,6 +98,10 @@ static void flush_tlb_func(void *info)
{
struct flush_tlb_info *f = info;

+ /* remove double counted irq_tlb_count from irq_call_count */
+ dec_irq_stat(irq_call_count);
+ inc_irq_stat(irq_tlb_count);
+
if (f->flush_mm != this_cpu_read(cpu_tlbstate.active_mm))
return;
===


Thanks
Alex
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