Commit-ID: 68271c6ae726d7ab51e39b7342c838761bf0a25c
Gitweb: http://git.kernel.org/tip/68271c6ae726d7ab51e39b7342c838761bf0a25c
Author: Ingo Molnar <mingo@xxxxxxxxxx>
AuthorDate: Mon, 27 Apr 2015 09:59:11 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 19 May 2015 15:47:54 +0200
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@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
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 b1fbbb8..41ea25a 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);
}
}
--
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