Re: [PATCH] mm: don't show nr_indirectly_reclaimable in /proc/vmstat

From: Vlastimil Babka
Date: Fri Apr 27 2018 - 05:17:12 EST

On 04/26/2018 11:55 PM, David Rientjes wrote:
> On Thu, 26 Apr 2018, Michal Hocko wrote:
>>> Don't show nr_indirectly_reclaimable in /proc/vmstat,
>>> because there is no need in exporting this vm counter
>>> to the userspace, and some changes are expected
>>> in reclaimable object accounting, which can alter
>>> this counter.
>>> Signed-off-by: Roman Gushchin <guro@xxxxxx>
>>> Cc: Vlastimil Babka <vbabka@xxxxxxx>
>>> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
>>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>>> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
>>> Cc: Michal Hocko <mhocko@xxxxxxxx>
>>> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
>> This is quite a hack. I would much rather revert the counter and fixed
>> it the way Vlastimil has proposed. But if there is a strong opposition
>> to the revert then this is probably the simples thing to do. Therefore
> Implementing this counter as a vmstat doesn't make much sense based on how
> it's used. Do you have a link to what Vlastimil proposed? I haven't seen
> mention of alternative ideas.

It was in the original thread, see e.g.

However it will take some time to get that in mainline, and meanwhile
the current implementation does prevent a DOS. So I doubt it can be
fully reverted - as a compromise I just didn't want the counter to
become ABI. TBH though, other people at LSF/MM didn't seem concerned
that /proc/vmstat is an ABI that we can't change (i.e. counters have
been presumably removed in the past already).