cc linux-xfs On Fri, Jul 05, 2019 at 10:33:04PM +0800, Yafang Shao wrote: > On Fri, Jul 5, 2019 at 7:10 PM Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > > > On Fri 05-07-19 17:41:44, Yafang Shao wrote: > > > On Fri, Jul 5, 2019 at 5:09 PM Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > [...] > > > > 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. > > > > Could you be more specific about obstacles with respect to interfaces > > please? > > > > Lots of applications will be changed. > Kubernetes, Docker and some other applications which are using cgroup v1, > that will be a trouble, because they are not maintained by us. > > > > 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. > > > > Are you sure? I would be surprised if v1 throttling would work while v2 > > wouldn't. As far as I remember it is v2 writeback throttling which > > actually works. The only throttling we have for v1 is reclaim based one > > which is a huge hammer. > > -- > > We did it in cgroup v1 in our kernel. > But the upstream still don't support it in cgroup v2. > So my real question is why upstream can't support such an import file system ? > Do you know which companies besides facebook are using cgroup v2 in > their product enviroment? > I think the original issue with regard to XFS cgroupv2 writeback throttling support was that at the time the XFS patch was proposed, there wasn't any test coverage to prove that the code worked (and the original author never followed up). That has since been resolved and Christoph has recently posted a new patch [1], which appears to have been accepted by the maintainer. Brian [1] https://marc.info/?l=linux-xfs&m=156138379906141&w=2 > Thanks > Yafang >
