lkml.org 
[lkml]   [2012]   [Apr]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH RFC] memcg: MEMCG_NR_FILE_MAPPED should update _STAT_CACHE as well
On Mon, Apr 23, 2012 at 05:35:12PM +0900, KAMEZAWA Hiroyuki wrote:
[...]
> > For example, looking into this code flow:
> >
> > -> page_add_file_rmap() (mm/rmap.c)
> > -> mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED) (include/linux/memcontrol.h)
> > -> void mem_cgroup_update_page_stat(page, MEMCG_NR_FILE_MAPPED, 1) (mm/memcontrol.c)
> >
> > And then:
> >
> > void mem_cgroup_update_page_stat(struct page *page,
> > enum mem_cgroup_page_stat_item idx, int val)
> > {
> > ...
> > switch (idx) {
> > case MEMCG_NR_FILE_MAPPED:
> > idx = MEM_CGROUP_STAT_FILE_MAPPED;
> > break;
> > default:
> > BUG();
> > }
> >
> > this_cpu_add(memcg->stat->count[idx], val);
> > ...
> > }
> >
> > So, clearly, this function only bothers updating _FILE_MAPPED only,
> > leaving _CACHE alone.
[...]
>
> NACK.
> CACHE is updated at charge()/uncharge()...inserting/removing page cache to radix-tree.

Interesting; true, we have charge/uncharge in __do_fault()/do_wp_page
and friends. So, we seem to update FILE_MAPPED in the rmap via
cgroup_dec/inc_page_stat, and CACHE is updated via charge/uncharge. Hm.

The code in memory.c is full of if/else ifs, and I wonder if there's
some discrepancy in there, but briefly looking it looks fine. The
code looks correct indeed, but I'm getting the wrong stats. :-/

Thanks,

--
Anton Vorontsov
Email: cbouatmailru@gmail.com


\
 
 \ /
  Last update: 2012-04-23 11:39    [W:0.048 / U:34.900 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site