Re: [RFC][PATCH 2/3] memcg: reduce size of struct page_cgroup.
From: Michal Hocko <hidden>
Date: 2012-03-22 13:11:20
Also in:
cgroups
On Mon 19-03-12 17:01:27, KAMEZAWA Hiroyuki wrote:
Now, page_cgroup->flags has only 3bits. Considering alignment of struct mem_cgroup, which is allocated by kmalloc(), we can encode pointer to mem_cgroup and flags into a word.
into a single word.
After this patch, pc->flags is encoded as 63 2 0 | pointer to memcg..........|flags|
Looks good. Acked-by: Michal Hocko <redacted>
quoted hunk ↗ jump to hunk
Signed-off-by: KAMEZAWA Hiroyuki <redacted> --- include/linux/page_cgroup.h | 15 ++++++++++++--- 1 files changed, 12 insertions(+), 3 deletions(-)diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h index 92768cb..bca5447 100644 --- a/include/linux/page_cgroup.h +++ b/include/linux/page_cgroup.h@@ -1,6 +1,10 @@ #ifndef __LINUX_PAGE_CGROUP_H #define __LINUX_PAGE_CGROUP_H +/* + * Because these flags are encoded into ->flags with a pointer, + * we cannot have too much flags.
^^^^^^^^^^^^^^ cannot have too many flags but an explicit BUILD_BUG_ON would be much more precise than a comment I guess. -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>