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Date: Tue, 5 May 2015 19:50:39 +0200
From: Ingo Molnar <mingo@...nel.org>
To: linux-kernel@...r.kernel.org
Cc: Andy Lutomirski <luto@...capital.net>,
Borislav Petkov <bp@...en8.de>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Fenghua Yu <fenghua.yu@...el.com>,
"H. Peter Anvin" <hpa@...or.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Oleg Nesterov <oleg@...hat.com>,
Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 147/208] 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@...en8.de>
Cc: Andy Lutomirski <luto@...capital.net>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Ingo Molnar <mingo@...nel.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 8835b802aa16..7fdeabc1f2af 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);
}
}
--
2.1.0
--
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