Re: [PATCH 1/3] mm: introduce NR_INDIRECTLY_RECLAIMABLE_BYTES

On Thu 12-04-18 08:52:52, Vlastimil Babka wrote:

On 04/11/2018 03:56 PM, Roman Gushchin wrote:

quoted

On Wed, Apr 11, 2018 at 03:16:08PM +0200, Vlastimil Babka wrote:

[...]

quoted

quoted

With that in mind, can we at least for now put the (manually maintained)
byte counter in a variable that's not directly exposed via /proc/vmstat,
and then when printing nr_slab_reclaimable, simply add the value
(divided by PAGE_SIZE), and when printing nr_slab_unreclaimable,
subtract the same value. This way we would be simply making the existing
counters more precise, in line with their semantics.

Idk, I don't like the idea of adding a counter outside of the vm counters
infrastructure, and I definitely wouldn't touch the exposed
nr_slab_reclaimable and nr_slab_unreclaimable fields.

Why?

We would be just making the reported values more precise wrt reality.

I was suggesting something similar in an earlier discussion. I am not
really happy about the new exposed counter either. It is just arbitrary
by name yet very specific for this particular usecase.

What is a poor user supposed to do with the new counter? Can this be
used for any calculations?
-- 
Michal Hocko
SUSE Lab