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Message-ID: <20080830102012.GA21145@basil.nowhere.org>
Date: Sat, 30 Aug 2008 12:20:12 +0200
From: Andi Kleen <andi@...stfloor.org>
To: x86@...nel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] Avoid double flush in do_tlb_flush_all()
Avoid double flush in do_tlb_flush_all()
leave_mm already flushes the TLBs, so don't need to flush directly before that
in do_flush_tlb_all(). Avoid the double flush.
Pointed out by Rainer Weikusat
Signed-off-by: Andi Kleen <ak@...ux.intel.com>
---
arch/x86/kernel/tlb_32.c | 5 ++---
arch/x86/kernel/tlb_64.c | 7 +++----
2 files changed, 5 insertions(+), 7 deletions(-)
Index: linux-2.6.27-rc4-misc/arch/x86/kernel/tlb_32.c
===================================================================
--- linux-2.6.27-rc4-misc.orig/arch/x86/kernel/tlb_32.c
+++ linux-2.6.27-rc4-misc/arch/x86/kernel/tlb_32.c
@@ -229,11 +229,10 @@ EXPORT_SYMBOL(flush_tlb_page);
static void do_flush_tlb_all(void *info)
{
- unsigned long cpu = smp_processor_id();
-
- __flush_tlb_all();
if (per_cpu(cpu_tlbstate, cpu).state == TLBSTATE_LAZY)
leave_mm(cpu);
+ else
+ __flush_tlb_all(smp_processor_id());
}
void flush_tlb_all(void)
Index: linux-2.6.27-rc4-misc/arch/x86/kernel/tlb_64.c
===================================================================
--- linux-2.6.27-rc4-misc.orig/arch/x86/kernel/tlb_64.c
+++ linux-2.6.27-rc4-misc/arch/x86/kernel/tlb_64.c
@@ -266,11 +266,10 @@ void flush_tlb_page(struct vm_area_struc
static void do_flush_tlb_all(void *info)
{
- unsigned long cpu = smp_processor_id();
-
- __flush_tlb_all();
if (read_pda(mmu_state) == TLBSTATE_LAZY)
- leave_mm(cpu);
+ leave_mm(smp_processor_id());
+ else
+ __flush_tlb_all();
}
void flush_tlb_all(void)
--
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