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Commit 16d9dbf0 authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge
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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: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
parent 2fcddce1

arch/x86/kernel/process_64.c

+3 −3
Original line number Diff line number Diff line
@@ -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.

	 */