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From: Brian Gerst <brgerst@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Tejun Heo <tj@kernel.org>, linux-kernel@vger.kernel.org
Subject: [PATCH 11/12] x86: Remove extra barriers from load_gs_base()
Date: Mon, 26 Jan 2009 01:15:31 -0500	[thread overview]
Message-ID: <1232950532-22923-11-git-send-email-brgerst@gmail.com> (raw)
In-Reply-To: <73c1f2160901252214k394d198dn815670e7f667b3ac@mail.gmail.com>

Impact: optimization

mb() generates an mfence instruction, which is not needed here.  Only
a compiler barrier is needed, and that is handled by the memory clobber
in the wrmsrl function.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
---
 arch/x86/include/asm/processor.h |    3 ---
 1 files changed, 0 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 32c30b0..794234e 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -397,10 +397,7 @@ DECLARE_PER_CPU(char *, irq_stack_ptr);
 
 static inline void load_gs_base(int cpu)
 {
-	/* Memory clobbers used to order pda/percpu accesses */
-	mb();
 	wrmsrl(MSR_GS_BASE, (unsigned long)per_cpu(irq_stack_union.gs_base, cpu));
-	mb();
 }
 #endif
 
-- 
1.6.1


  parent reply	other threads:[~2009-01-26  6:19 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-26  6:14 [PATCH 0/12] Next batch of x86 percpu changes Brian Gerst
2009-01-26  6:15 ` [PATCH 01/12] x86: Merge setup_per_cpu_maps() into setup_per_cpu_areas() Brian Gerst
2009-01-26  6:15 ` [PATCH 02/12] x86: Move 64-bit NUMA code Brian Gerst
2009-01-26  6:15 ` [PATCH 03/12] x86: Move setup_cpu_local_masks() Brian Gerst
2009-01-26  6:15 ` [PATCH 04/12] x86: Always page-align per-cpu area start and size Brian Gerst
2009-01-26  6:15 ` [PATCH 05/12] x86: Move apic variables to apic.c Brian Gerst
2009-01-26  6:15 ` [PATCH 06/12] x86: Only compile setup_percpu.o on SMP Brian Gerst
2009-01-26  6:15 ` [PATCH 07/12] x86: Move this_cpu_offset Brian Gerst
2009-01-26  6:15 ` [PATCH 08/12] x86: Don't assume boot cpu is #0 Brian Gerst
2009-01-26  6:15 ` [PATCH 09/12] x86: Make Voyager use x86 per-cpu setup Brian Gerst
2009-01-26  6:15 ` [PATCH 10/12] x86: Initialize per-cpu GDT segment in " Brian Gerst
2009-01-26  6:15 ` Brian Gerst [this message]
2009-01-26  6:15 ` [PATCH 12/12] x86: Load new GDT after setting up boot cpu per-cpu area Brian Gerst

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