diff options
author | Christoph Lameter <cl@linux.com> | 2010-12-08 10:22:55 -0500 |
---|---|---|
committer | Tejun Heo <tj@kernel.org> | 2010-12-17 09:07:19 -0500 |
commit | 909ea96468096b07fbb41aaf69be060d92bd9271 (patch) | |
tree | a7e015edd96b5f674874fe78cdd889769e130a2a /include/asm-generic/irq_regs.h | |
parent | 780f36d8b3fa9572f731d4fb85067b2e45e6f993 (diff) |
core: Replace __get_cpu_var with __this_cpu_read if not used for an address.
__get_cpu_var() can be replaced with this_cpu_read and will then use a
single read instruction with implied address calculation to access the
correct per cpu instance.
However, the address of a per cpu variable passed to __this_cpu_read()
cannot be determined (since it's an implied address conversion through
segment prefixes). Therefore apply this only to uses of __get_cpu_var
where the address of the variable is not used.
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Hugh Dickins <hughd@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'include/asm-generic/irq_regs.h')
-rw-r--r-- | include/asm-generic/irq_regs.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/include/asm-generic/irq_regs.h b/include/asm-generic/irq_regs.h index 5ae1d07d4a1..6bf9355fa7e 100644 --- a/include/asm-generic/irq_regs.h +++ b/include/asm-generic/irq_regs.h | |||
@@ -22,15 +22,15 @@ DECLARE_PER_CPU(struct pt_regs *, __irq_regs); | |||
22 | 22 | ||
23 | static inline struct pt_regs *get_irq_regs(void) | 23 | static inline struct pt_regs *get_irq_regs(void) |
24 | { | 24 | { |
25 | return __get_cpu_var(__irq_regs); | 25 | return __this_cpu_read(__irq_regs); |
26 | } | 26 | } |
27 | 27 | ||
28 | static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs) | 28 | static inline struct pt_regs *set_irq_regs(struct pt_regs *new_regs) |
29 | { | 29 | { |
30 | struct pt_regs *old_regs, **pp_regs = &__get_cpu_var(__irq_regs); | 30 | struct pt_regs *old_regs; |
31 | 31 | ||
32 | old_regs = *pp_regs; | 32 | old_regs = __this_cpu_read(__irq_regs); |
33 | *pp_regs = new_regs; | 33 | __this_cpu_write(__irq_regs, new_regs); |
34 | return old_regs; | 34 | return old_regs; |
35 | } | 35 | } |
36 | 36 | ||