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Message-Id: <1244748040-27185-5-git-send-email-jeremy@goop.org>
Date: Thu, 11 Jun 2009 12:20:39 -0700
From: Jeremy Fitzhardinge <jeremy@...p.org>
To: Ingo Molnar <mingo@...e.hu>
Cc: the arch/x86 maintainers <x86@...nel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>,
Alok Kataria <akataria@...are.com>,
Rusty Russell <rusty@...tcorp.com.au>
Subject: [PATCH 4/5] x86-64: move unlazy_fpu() into lazy cpu state part of context switch
From: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Make sure that unlazy_fpu()'s stts gets batched along with the other
cpu state changes during context switch. (32-bit already does this.)
This makes sure it gets batched when running paravirtualized.
[ Impact: optimise paravirtual FPU context switch ]
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@...rix.com>
Cc: Alok Kataria <akataria@...are.com>
Cc: Rusty Russell <rusty@...tcorp.com.au>
---
arch/x86/kernel/process_64.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 89c46f1..6ed1c57 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -432,6 +432,9 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
load_TLS(next, cpu);
+ /* Must be after DS reload */
+ unlazy_fpu(prev_p);
+
/*
* Leave lazy mode, flushing any hypercalls made here.
* This must be done before restoring TLS segments so
@@ -472,9 +475,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
prev->gsindex = gsindex;
- /* Must be after DS reload */
- unlazy_fpu(prev_p);
-
/*
* Switch the PDA and FPU contexts.
*/
--
1.6.2.2
--
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