On Fri, Jul 5, 2019 at 5:09 PM Michal Hocko <mhocko@xxxxxxxxxx> wrote:
>
> On Fri 05-07-19 15:05:30, Yafang Shao wrote:
> > We always deploy many containers on one host. Some of these containers
> > are with high priority, while others are with low priority.
> > memory.{min, low} is useful to help us protect page cache of a specified
> > container to gain better performance.
> > But currently it is only supported in cgroup v2.
> > To support it in cgroup v1, we only need to make small changes, as the
> > facility is already exist.
> > This patch exposed two files to user in cgroup v1, which are memory.min
> > and memory.low. The usage to set these two files is same with cgroup v2.
> > Both hierarchical and non-hierarchical mode are supported.
>
> Cgroup v1 API is considered frozen with new features added only to v2.
The facilities support both cgroup v1 and cgroup v2, and what we need
to do is only exposing the interface.
If the cgroup v1 API is frozen, it will be a pity.
> Why cannot you move over to v2 and have to stick with v1?
Because the interfaces between cgroup v1 and cgroup v2 are changed too
much, which is unacceptable by our customer.
It may take long time to use cgroup v2 in production envrioment, per
my understanding.
BTW, the filesystem on our servers is XFS, but the cgroup v2
writeback throttle is not supported on XFS by now, that is beyond my
comprehension.
Thanks
Yafang
