From 68271c6ae726d7ab51e39b7342c838761bf0a25c Mon Sep 17 00:00:00 2001 From: Ingo Molnar <mingo@kernel.org> Date: Mon, 27 Apr 2015 09:59:11 +0200 Subject: [PATCH] x86/fpu: Optimize fpu_copy() Optimize fpu_copy() a bit by expanding the ->fpstate_active == 1 portion of fpu__save() into it. ( The main purpose of this change is to enable another, larger optimization that will be done in the next patch. ) Reviewed-by: Borislav Petkov <bp@alien8.de> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/kernel/fpu/core.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index b1fbbb8eb934..41ea25a61b5f 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -224,7 +224,10 @@ static void fpu_copy(struct fpu *dst_fpu, struct fpu *src_fpu) memset(&dst_fpu->state.xsave, 0, xstate_size); copy_fpregs_to_fpstate(dst_fpu); } else { - fpu__save(src_fpu); + preempt_disable(); + if (!copy_fpregs_to_fpstate(src_fpu)) + fpregs_deactivate(src_fpu); + preempt_enable(); memcpy(&dst_fpu->state, &src_fpu->state, xstate_size); } } -- 2.20.1