From: Jeremy Fitzhardinge Date: Fri, 24 Apr 2009 07:50:27 +0000 (-0700) Subject: x86-64: move unlazy_fpu() into lazy cpu state part of context switch X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=16d9dbf0c2bd167fdd942b83592d59696c7b73bd;p=linux-beck.git x86-64: move unlazy_fpu() into lazy cpu state part of context switch 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 Cc: Alok Kataria Cc: Rusty Russell --- diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index ebefb5407b9d..c9b8904736db 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -419,6 +419,9 @@ __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 @@ -459,9 +462,6 @@ __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. */