(2012/05/17 8:01), Andrew Morton wrote:
> On Mon, 14 May 2012 20:00:51 +0200
> Johannes Weiner <hannes@xxxxxxxxxxx> wrote:
>
>> Directly print statistics and event counters instead of going through
>> an intermediate accumulation stage into a separate array, which used
>> to require defining statistic items in more than one place.
>>
>> ...
>>
>> -static const char *memcg_stat_strings[NR_MCS_STAT] = {
>> - "cache",
>> - "rss",
>> - "mapped_file",
>
> Bah humbug, who went and called this mapped_file?
>
> This stat is derived from MEM_CGROUP_STAT_FILE_MAPPED. But if we
> rename MEM_CGROUP_STAT_FILE_MAPPED to MEM_CGROUP_STAT_MAPPED_FILE then
> we also need to rename the non-memcg NR_FILE_MAPPED. And we can't
> change the text to "file_mapped" because it's ABI.
>
Sorry..
>> - "mlock",
>> - "swap",
>
> And "swap" is derived from MEM_CGROUP_STAT_SWAPOUT. We could rename
> that to MEM_CGROUP_STAT_SWAP without trouble.
>
Yes.
> But both are poor names. There are two concepts here: a) swapout
> events (ie: swap writeout initiation) and b) swapspace usage. Type a)
> only ever counts up, whereas type b) counts up and down.
>
> MEM_CGROUP_STAT_SWAPOUT is actually of type b), but "swapout" is a
> misleading term, because it refers to type a) events.
>
I'll prepare a patch.
> And the human-displayed "swap" is useless because it can refer to
> either type a) or type b) events. These should be called "swapped" and
> MEM_CGROUP_STAT_SWAPPED. But we can't change the userspace interface.
>
> argh, I hate you all!
>
Hm...sorry. I(fujitsu) am now considering to add meminfo for memcg...,
add an option to override /proc/meminfo if a task is in container or
meminfo file somewhere.
(Now, we cannot trust /usr/bin/free, /usr/bin/top etc...in a container.)
so...I think usual user experience will be better because of the same format
with meminfo.
Thanks,
-Kame
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