Hello, Currently, struct cgroup * is used as the main interface handle between cgroup core and its subsystems, which works but is a bit clunky because subsystems usually care much more about css's (cgroup_subsys_state) a lot more than cgroups, which is natural as a css is the intersection between a cgroup and a subsystem. In addition to being a bit clunky, dealing with cgroups directly pose a bit of trouble for the planned unified hierarchy support on two fronts. First, most iterations become subsystem dependent as task membership is affected by which subtree has the specific subsystem enabled and thus require specifying which subsystem the iteration is for, which is automatically achieved if the interfaces deal with css's instead of cgroups. Second, as css's may be created, attached, detached and destroyed dynamically multiple times across the lifetime of a given cgroup as they're enabled and disabled, which makes cgroup -> css mapping much more difficult to synchronize. Giving out cgroup to subsystems and then requiring them to take the extra steps to deal with their css's coming and going dynamically is a lot more fragile than cgroup core proper handling it internally and giving out the resulting css's to subsystems. So, this patchset converts all cgroup subsystem APIs to deal with css's instead of cgroups. The patchset is fairly large but most of the conversions, while being tedious, aren't complex. At the end of series, subsystems no longer make cgroup -> css mapping themselves and cgroup_css() - formerly cgroup_subsys_state() - is made internal to cgroup core proper. This is a rather large update to the interface and likely to play as a barrier when porting commits, which is inconvenient but also provides an opportunity to clean up the API where we can as doing so won't significantly raise the level of inconvenience. As such, this patchset contains some API cleanups and I'll probably follow up with further API updates that I've been meaning to do and, if you have some good idea to clean up cgroup internal API, this probably is a good time to submit it. This patchset contains the following 23 patches. 0001-cgroup-s-cgroup_subsys_state-cgroup_css-s-task_subsy.patch 0002-cpuset-drop-const-qualifiers-from-struct-cpuset-inst.patch 0003-netprio_cgroup-pass-around-css-instead-of-cgroup-and.patch 0004-hugetlb_cgroup-pass-around-hugetlb_cgroup-instead-of.patch 0005-cgroup-add-subsystem-pointer-to-cgroup_subsys_state.patch 0006-cgroup-add-update-accessors-which-obtain-subsys-spec.patch 0007-cgroup-add-css_parent.patch 0008-cgroup-pass-around-cgroup_subsys_state-instead-of-cg.patch 0009-cgroup-add-subsys-backlink-pointer-to-cftype.patch 0010-cgroup-pin-cgroup_subsys_state-when-opening-a-cgroup.patch 0011-cgroup-add-cgroup-dummy_css.patch 0012-cgroup-pass-around-cgroup_subsys_state-instead-of-cg.patch 0013-cgroup-convert-cgroup_next_sibling-to-cgroup_next_ch.patch 0014-cgroup-always-use-cgroup_next_child-to-walk-the-chil.patch 0015-cgroup-make-hierarchy-iterators-deal-with-cgroup_sub.patch 0016-cgroup-relocate-cgroup_advance_iter.patch 0017-cgroup-rename-cgroup_iter-to-cgroup_task_iter.patch 0018-cgroup-make-cgroup_task_iter-remember-the-cgroup-bei.patch 0019-cgroup-remove-struct-cgroup_scanner.patch 0020-cgroup-make-task-iterators-deal-with-cgroup_subsys_s.patch 0021-cgroup-make-cftype-un-register_event-deal-with-cgrou.patch 0022-cgroup-make-cgroup_taskset-deal-with-cgroup_subsys_s.patch 0023-cgroup-unexport-cgroup_css.patch 0001-0007 prepare for css-based interface. Individual subsystems are updated so that they're easier to convert and css_parent() is added so that upward travelsal can be done without going through cgroup. 0008 updates all subsystem methods. 0009-0012 update file operations. 0013-0015 update hierarchy iterators. 0016-0020 update task iterators. 0021 updates events. 0022 updates task_set handling. 0023 unexports cgroup_css(). This patchset is available in the following git branch. git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git review-cssfy diffstat follows. block/blk-cgroup.c | 41 +- block/blk-cgroup.h | 34 - block/blk-throttle.c | 40 +- block/cfq-iosched.c | 90 ++-- fs/bio.c | 2 include/linux/cgroup.h | 268 +++++++------- include/linux/memcontrol.h | 2 include/linux/vmpressure.h | 6 include/net/cls_cgroup.h | 4 include/net/netprio_cgroup.h | 8 kernel/cgroup.c | 798 ++++++++++++++++++++++++------------------- kernel/cgroup_freezer.c | 128 +++--- kernel/cpuset.c | 265 ++++++-------- kernel/events/core.c | 22 - kernel/sched/core.c | 113 +++--- kernel/sched/cpuacct.c | 51 +- kernel/sched/sched.h | 6 mm/hugetlb_cgroup.c | 69 +-- mm/memcontrol.c | 216 +++++------ mm/vmpressure.c | 25 - net/core/netprio_cgroup.c | 72 +-- net/ipv4/tcp_memcontrol.c | 12 net/sched/cls_cgroup.c | 39 +- security/device_cgroup.c | 63 +-- 24 files changed, 1210 insertions(+), 1164 deletions(-) Thanks. -- tejun _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/containers
