Re: [PATCH] add vmalloc stats to meminfo

[Martin J. Bligh]

>> Some workloads like to eat up a lot of vmalloc space.
> 
> Which workloads are those?
> 
>>  It is often hard to tell
>> whether this is because the area is too small, or just too fragmented.  This
>> makes it easy to determine.
> 
> I do not recall ever having seen any bug/problem reports which this patch
> would have helped to solve.  Could you explain in more detai why is it useful?

Seen on specweb - doubling the size of the vmalloc space made it go
away, but without any counters, it was all really just guesswork.

I am also going to implement per-node slabcache on top of vmalloc,
as slabs have to be in permanently mapped KVA, but all ZONE_NORMAL
is on node 0. That's going to put a lot of pressure on the vmalloc
area.

M.