vmstat: Optimize zone counter modifications through the use of this cpu operations
authorChristoph Lameter <cl@linux.com>
Mon, 6 Dec 2010 17:16:20 +0000 (11:16 -0600)
committerTejun Heo <tj@kernel.org>
Fri, 17 Dec 2010 14:07:18 +0000 (15:07 +0100)
commit12938a9220a38d555e38dc9b40021e664b99a1f1
tree978c0199dcd22faf92250fcfd5bfa2aac1100baa
parent819a72af8d6653daa48334f24ce0a935ccdd33c7
vmstat: Optimize zone counter modifications through the use of this cpu operations

this cpu operations can be used to slightly optimize the function. The
changes will avoid some address calculations and replace them with the
use of the percpu segment register.

If one would have this_cpu_inc_return and this_cpu_dec_return then it
would be possible to optimize inc_zone_page_state and
dec_zone_page_state even more.

V1->V2:
- Fix __dec_zone_state overflow handling
- Use s8 variables for temporary storage.

V2->V3:
- Put __percpu annotations in correct places.

Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
mm/vmstat.c