From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754238Ab1IMFbr (ORCPT ); Tue, 13 Sep 2011 01:31:47 -0400 Received: from mga14.intel.com ([143.182.124.37]:39606 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752302Ab1IMFbq (ORCPT ); Tue, 13 Sep 2011 01:31:46 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.68,372,1312182000"; d="scan'208";a="16454953" Subject: Re: [patch] x86: tlb flush avoid superflous leave_mm() From: Shaohua Li To: lkml Cc: Ingo Molnar , hpa@linux.intel.com In-Reply-To: <1314947277.29510.66.camel@sli10-conroe> References: <1314947277.29510.66.camel@sli10-conroe> Content-Type: text/plain; charset="UTF-8" Date: Tue, 13 Sep 2011 13:35:15 +0800 Message-ID: <1315892115.29510.89.camel@sli10-conroe> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2011-09-02 at 15:07 +0800, Shaohua Li wrote: > 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. ping, any comments? > Signed-off-by: Shaohua Li > > 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); >