On 8/17/20 12:56 PM, Chris Down wrote:

Shakeel Butt writes:

quoted

quoted

Sometimes, memory reclaim may not be able to recover memory in a rate
that can catch up to the physical memory allocation rate especially
when rotating disks are used for swapping or writing dirty pages. In
this case, the physical memory consumption will keep on increasing.

Isn't this the real underlying issue? Why not make the guarantees of
memory.high more strict instead of adding more interfaces and
complexity?

Oh, thanks Shakeel for bringing this up. I missed this in the original 
changelog and I'm surprised that it's mentioned, since we do have 
protections against that.

Waiman, we already added artificial throttling if memory reclaim is 
not sufficiently achieved in 0e4b01df8659 ("mm, memcg: throttle 
allocators when failing reclaim over memory.high"), which has been 
present since v5.4. This should significantly inhibit physical memory 
consumption from increasing. What problems are you having with that? :-)

Oh, I think I overlooked your patch. You are right. There are already 
throttling in place. So I need to re-examine my patch to see if it is 
still necessary or reduce the scope of the patch.

Thanks,
Longman