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

On 04/26/2018 11:55 PM, David Rientjes wrote:

On Thu, 26 Apr 2018, Michal Hocko wrote:

quoted

quoted

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 <redacted>
Cc: Vlastimil Babka <redacted>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>

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.
[ref]

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).