On 2015/5/19 3:49, Tejun Heo wrote: > Hello, > > When a controller is enabled or disabled on the unified hierarchy, the > effective css changes for all processes in the sub-hierarchy which > virtually is multi-process migration. This is implemented in > cgroup_update_dfl_csses() as process-by-process migration - all the > target source css_sets are first chained to the target list and > processes are drained from them one-by-one. > > If a process gets rejected by a controller after some are successfully > migrated, the recovery action is tricky. The changes which have > happened upto this point have to be rolled back but there's nothing > guaranteeing such rollback would be successful either. > > The unified hierarchy didn't need to deal with this issue because > organizational operations were expected to always succeed; > unfortunately, it turned out that such policy doesn't work too well > for certain type of resources and unified hierarchy would need to > allow migration failures for some restrictied cases. > > This patch updates multi-process migration in > cgroup_update_dfl_csses() atomic so that ->can_attach() can fail the > whole transaction. It's consisted of the following seven patches. > > 0001-cpuset-migrate-memory-only-for-threadgroup-leaders.patch > 0002-memcg-restructure-mem_cgroup_can_attach.patch > 0003-memcg-immigrate-charges-only-when-a-threadgroup-lead.patch > 0004-cgroup-memcg-cpuset-implement-cgroup_taskset_for_eac.patch > 0005-reorder-cgroup_migrate-s-parameters.patch > 0006-cgroup-separate-out-taskset-operations-from-cgroup_m.patch > 0007-cgroup-make-cgroup_update_dfl_csses-migrate-all-targ.patch > Thanks for working on this. The patchset looks good to me. Acked-by: Zefan Li <lizefan@xxxxxxxxxx> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>