On Tue 10-07-12 14:54:48, Wanpeng Li wrote:

On Tue, Jul 10, 2012 at 08:21:04AM +0200, Michal Hocko wrote:

quoted

On Tue 10-07-12 14:10:21, Wanpeng Li wrote:

quoted

On Mon, Jul 09, 2012 at 05:20:58PM +0200, Michal Hocko wrote:

quoted

On Thu 05-07-12 02:45:00, Johannes Weiner wrote:

quoted

It does not matter to __mem_cgroup_try_charge() if the passed mm is
NULL or init_mm, it will charge the root memcg in either case.

You can also change the comment in __mem_cgroup_try_charge :

"if so charge the init_mm" => "if so charge the root memcg"

This is already in place:
"
If mm is NULL and the caller doesn't pass a valid memcg pointer, that is
treated as a charge to root_mem_cgroup.
"

IIUC, if still keep comment "if so charge the init_mm" is not correct,
since pages in pagecache aren't mapped into any processes' ptes, 
so mm is NULL, and these pages which in pagecache are not belong 
to init_mm, the comment should be changed. :-)

Fair enough. I guess Johannes will change that in the next post.
-- 
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9    
Czech Republic