memcg: do not recalculate section unnecessarily in init_section_page_cgroup
authorFernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Thu, 8 Jan 2009 02:07:51 +0000 (18:07 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 8 Jan 2009 16:31:04 +0000 (08:31 -0800)
commit0753b0ef3b301895234fed02bea2c099c7ff4feb
tree35d01368e76d0e5ad21b38fc80274154f8a35d62
parent01b1ae63c2270cbacfd43fea94578c17950eb548
memcg: do not recalculate section unnecessarily in init_section_page_cgroup

In init_section_page_cgroup() the section a given pfn belongs to is
calculated at the top of the function and, despite the fact that the
pfn/section correspondence does not change, it is recalculated further
down the same function.  By computing this just once and reusing that
value we save some bytes in the object file and do not waste CPU cycles.

Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_cgroup.c