linux-kernel - [PATCH x86 for review II] [20/39] i386: Small cleanup to TLB flush code

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Date:	Mon, 12 Feb 2007 08:38:07 +0100 (CET)
From:	Andi Kleen <ak@...e.de>
To:	patches@...-64.org, linux-kernel@...r.kernel.org
Subject: [PATCH x86 for review II] [20/39] i386: Small cleanup to TLB flush code


- Remove outdated comment
- Use cpu_relax() in a busy loop

Signed-off-by: Andi Kleen <ak@...e.de>

---
 arch/i386/kernel/smp.c |    5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

Index: linux/arch/i386/kernel/smp.c
===================================================================
--- linux.orig/arch/i386/kernel/smp.c
+++ linux/arch/i386/kernel/smp.c
@@ -375,8 +375,7 @@ static void flush_tlb_others(cpumask_t c
 	/*
 	 * i'm not happy about this global shared spinlock in the
 	 * MM hot path, but we'll see how contended it is.
-	 * Temporarily this turns IRQs off, so that lockups are
-	 * detected by the NMI watchdog.
+	 * AK: x86-64 has a faster method that could be ported.
 	 */
 	spin_lock(&tlbstate_lock);
 	
@@ -401,7 +400,7 @@ static void flush_tlb_others(cpumask_t c
 
 	while (!cpus_empty(flush_cpumask))
 		/* nothing. lockup detection does not belong here */
-		mb();
+		cpu_relax();
 
 	flush_mm = NULL;
 	flush_va = 0;
-
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