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 <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
---
 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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to