linux

iv/linux

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Ingo Molnar aeb997b9f2 x86/fpu: Change fpu->fpregs_active from 'int' to 'char', add lazy switching comments

Improve the memory layout of 'struct fpu':

 - change ->fpregs_active from 'int' to 'char' - it's just a single flag
   and modern x86 CPUs can do efficient byte accesses.

 - pack related fields closer to each other: often 'fpu->state' will not be
   touched, while the other fields will - so pack them into a group.

Also add comments to each field, describing their purpose, and add
some background information about lazy restores.

Also fix an obsolete, lazy switching related comment in fpu_copy()'s description.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
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>

2015-05-19 15:48:09 +02:00

api.h

x86/fpu: Introduce cpu_has_xfeatures(xfeatures_mask, feature_name)

2015-05-19 15:47:55 +02:00

internal.h

x86/fpu: Harmonize FPU register state types

2015-05-19 15:48:09 +02:00

regset.h

x86/fpu: Factor out fpu/regset.h from fpu/internal.h

2015-05-19 15:48:06 +02:00

signal.h

x86/fpu: Factor out fpu/signal.c