Andrea Righi wrote: > On Fri, Apr 17, 2009 at 09:56:31AM +0800, Li Zefan wrote: >> KAMEZAWA Hiroyuki wrote: >>> On Tue, 14 Apr 2009 22:21:12 +0200 >>> Andrea Righi <righi.andrea@xxxxxxxxx> wrote: >>> >>>> +Example: >>>> +* Create an association between an io-throttle group and a bio-cgroup group >>>> + with "bio" and "blockio" subsystems mounted in different mount points: >>>> + # mount -t cgroup -o bio bio-cgroup /mnt/bio-cgroup/ >>>> + # cd /mnt/bio-cgroup/ >>>> + # mkdir bio-grp >>>> + # cat bio-grp/bio.id >>>> + 1 >>>> + # mount -t cgroup -o blockio blockio /mnt/io-throttle >>>> + # cd /mnt/io-throttle >>>> + # mkdir foo >>>> + # echo 1 > foo/blockio.bio_id >>> Why do we need multiple cgroups at once to track I/O ? >>> Seems complicated to me. >>> >> IIUC, it also disallows other subsystems to be binded with blockio subsys: >> # mount -t cgroup -o blockio cpuset xxx /mnt >> (failed) >> >> and if a task is moved from cg1(id=1) to cg2(id=2) in bio subsys, this task >> will be moved from CG1(id=1) to CG2(id=2) automatically in blockio subsys. >> >> All these are odd, unexpected, complex and bug-prone I think.. > > Implementing bio-cgroup functionality as pure infrastructure framework > instead of a cgroup subsystem would remove all this oddity and > complexity. Andrea, I agree with you completely. In fact, we have been working on that for a while and have just proposed doing exactly that on a different mail thread (you are CC'ed). It would be great if you could comment on that proposal. Thanks, Fernando > For example, the actual functionality that I need for the io-throttle > controller is just an interface to set and get the cgroup owner of a > page. I think it should be the same also for other potential users of > bio-cgroup. > > So, what about implementing the bio-cgroup functionality as cgroup "page > tracking" infrastructure and provide the following interfaces: > > /* > * Encode the cgrp->css.id in page_group->flags > */ > void set_cgroup_page_owner(struct page *page, struct cgroup *cgrp); > > /* > * Returns the cgroup owner of a page, decoding the cgroup id from > * page_cgroup->flags. > */ > struct cgroup *get_cgroup_page_owner(struct page *page); > > This also wouldn't increase the size of page_cgroup because we can > encode the cgroup id in the unused bits of page_cgroup->flags, as > originally suggested by Kame. > > And I think it could be used also by dm-ioband, even if it's not a > cgroup-based subsystem... but I may be wrong. Ryo what's your opinion? > > -Andrea _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
