Messages in this thread Patch in this message | | | Subject | [patch] x86: tlb flush avoid superflous leave_mm() | From | Shaohua Li <> | Date | Fri, 02 Sep 2011 15:07:57 +0800 |
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If just one page VA tlb is required to be flushed and current task is in lazy TLB state, doing leave_mm() is superfluous because it flushes the whole TLB. This can reduce some TLB miss.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index d6c0418..3041665 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -153,13 +153,13 @@ void smp_invalidate_interrupt(struct pt_regs *regs) */ if (f->flush_mm == percpu_read(cpu_tlbstate.active_mm)) { - if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK) { - if (f->flush_va == TLB_FLUSH_ALL) + if (f->flush_va == TLB_FLUSH_ALL) { + if (percpu_read(cpu_tlbstate.state) == TLBSTATE_OK) local_flush_tlb(); else - __flush_tlb_one(f->flush_va); + leave_mm(cpu); } else - leave_mm(cpu); + __flush_tlb_one(f->flush_va); } out: ack_APIC_irq(); @@ -306,12 +306,8 @@ void flush_tlb_page(struct vm_area_struct *vma, unsigned long va) preempt_disable(); - if (current->active_mm == mm) { - if (current->mm) - __flush_tlb_one(va); - else - leave_mm(smp_processor_id()); - } + if (current->active_mm == mm) + __flush_tlb_one(va); if (cpumask_any_but(mm_cpumask(mm), smp_processor_id()) < nr_cpu_ids) flush_tlb_others(mm_cpumask(mm), mm, va);
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