Hello, Linus.
A lot of activities on the cgroup front. Most changes aren't visible
to userland at all at this point and are laying foundation for the
planned unified hierarchy.
* The biggest change is decoupling the lifetime management of css
(cgroup_subsys_state) from that of cgroup's. Because controllers
(cpu, memory, block and so on) will need to be dynamically enabled
and disabled, css which is the association point between a cgroup
and a controller may come and go dynamically across the lifetime of
a cgroup. Till now, css's were created when the associated cgroup
was created and stayed till the cgroup got destroyed.
Assumptions around this tight coupling permeated through cgroup core
and controllers. These assumptions are gradually removed, which
consists bulk of patches, and css destruction path is completely
decoupled from cgroup destruction path. Note that decoupling of
creation path is relatively easy on top of these changes and the
patchset is pending for the next window.
* cgroup has its own event mechanism cgroup.event_control, which is
only used by memcg. It is overly complex trying to achieve high
flexibility whose benefits seem dubious at best. Going forward, new
events will simply generate file modified event and the existing
mechanism is being made specific to memcg. This pull request
contains prepatory patches for such change.
* Various fixes and cleanups.
Merging into master 2f01ea908b ("Merge tag 'tty-3.12-rc1' of
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty") generates
one conflict in kernel/cgroup.c.
/*
<<<<<<< HEAD
* Make sure there's no live children. We can't test ->children
* emptiness as dead children linger on it while being destroyed;
* otherwise, "rmdir parent/child parent" may fail with -EBUSY.
*/
empty = true;
rcu_read_lock();
list_for_each_entry_rcu(child, &cgrp->children, sibling) {
empty = cgroup_is_dead(child);
if (!empty)
break;
}
rcu_read_unlock();
if (!empty)
return -EBUSY;
/*
* Block new css_tryget() by killing css refcnts. cgroup core
...
=======
* Initiate massacre of all css's. cgroup_destroy_css_killed()
* will be invoked to perform the rest of destruction once the
* percpu refs of all css's are confirmed to be killed.
>>>>>>> d1625964da51bda61306ad3ec45307a799c21f08
*/
for_each_root_subsys(cgrp->root, ss)
kill_css(cgroup_css(cgrp, ss));
This is the last minute fix bb78a92f47 ("cgroup: fix rmdir EBUSY
regression in 3.11") which was merged after v3.11-rc7 conflicting with
updates in for-3.12 and can be resolved by taking only the emptiness
check part from master.
/*
* Make sure there's no live children. We can't test ->children
* emptiness as dead children linger on it while being destroyed;
* otherwise, "rmdir parent/child parent" may fail with -EBUSY.
*/
empty = true;
rcu_read_lock();
list_for_each_entry_rcu(child, &cgrp->children, sibling) {
empty = cgroup_is_dead(child);
if (!empty)
break;
}
rcu_read_unlock();
if (!empty)
return -EBUSY;
/*
* Initiate massacre of all css's. cgroup_destroy_css_killed()
* will be invoked to perform the rest of destruction once the
* percpu refs of all css's are confirmed to be killed.
*/
for_each_root_subsys(cgrp->root, ss)
kill_css(cgroup_css(cgrp, ss));
Just in case, the following branch has an example merge.
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git test-merge-3.12
I pulled for-3.11-fixes into for-3.12 once during the last devel cycle
and git-request-pull got confused when generating diffstat, so I
generated it manually by diffing master against test-merge-3.12.
Thanks.
The following changes since commit da0a12caffad2eeadea429f83818408e7b77379a:
cgroup: fix a leak when percpu_ref_init() fails (2013-07-31 06:13:25 -0400)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-3.12
for you to fetch changes up to d1625964da51bda61306ad3ec45307a799c21f08:
cgroup: fix cgroup_css() invocation in css_from_id() (2013-08-27 14:27:23 -0400)
----------------------------------------------------------------
Li Zefan (10):
cgroup: remove sparse tags from offline_css()
cgroup: remove struct cgroup_seqfile_state
cgroup: more naming cleanups
cgroup: convert cgroup_ida to cgroup_idr
cgroup: document how cgroup IDs are assigned
cgroup: implement cgroup_from_id()
cgroup: restructure the failure path in cgroup_write_event_control()
cgroup: rename cgroup_pidlist->mutex
cpuset: remove an unncessary forward declaration
cgroup: change cgroup_from_id() to css_from_id()
Li Zhong (1):
cgroup: use css_get() in cgroup_create() to check CSS_ROOT
Tejun Heo (57):
cgroup: minor updates around cgroup_clear_directory()
cgroup: fix error path of cgroup_addrm_files()
cgroup: fix cgroup_add_cftypes() error handling
cgroup: separate out cgroup_base_files[] handling out of cgroup_populate/clear_dir()
cgroup: update error handling in cgroup_populate_dir()
cgroup: use for_each_subsys() instead of for_each_root_subsys() in cgroup_populate/clear_dir()
cgroup: make rebind_subsystems() handle file additions and removals with proper error handling
cgroup: move number_of_cgroups test out of rebind_subsystems() into cgroup_remount()
cgroup: move module ref handling into rebind_subsystems()
cgroup: remove gratuituous BUG_ON()s from rebind_subsystems()
cgroup: Merge branch 'for-3.11-fixes' into for-3.12
cgroup: s/cgroup_subsys_state/cgroup_css/ s/task_subsys_state/task_css/
cpuset: drop "const" qualifiers from struct cpuset instances
netprio_cgroup: pass around @css instead of @cgroup and kill struct cgroup_netprio_state
hugetlb_cgroup: pass around @hugetlb_cgroup instead of @cgroup
cgroup: add subsystem pointer to cgroup_subsys_state
cgroup: add/update accessors which obtain subsys specific data from css
cgroup: add css_parent()
cgroup: pass around cgroup_subsys_state instead of cgroup in subsystem methods
cgroup: add subsys backlink pointer to cftype
cgroup: pin cgroup_subsys_state when opening a cgroupfs file
cgroup: add cgroup->dummy_css
cgroup: pass around cgroup_subsys_state instead of cgroup in file methods
cgroup: convert cgroup_next_sibling() to cgroup_next_child()
cgroup: always use cgroup_next_child() to walk the children list
cgroup: make hierarchy iterators deal with cgroup_subsys_state instead of cgroup
cgroup: relocate cgroup_advance_iter()
cgroup: rename cgroup_iter to cgroup_task_iter
cgroup: make cgroup_task_iter remember the cgroup being iterated
cgroup: remove struct cgroup_scanner
cgroup: make task iterators deal with cgroup_subsys_state instead of cgroup
cgroup: make cftype->[un]register_event() deal with cgroup_subsys_state instead of cgroup
cgroup: make cgroup_taskset deal with cgroup_subsys_state instead of cgroup
cgroup: unexport cgroup_css()
cgroup: make css_for_each_descendant() and friends include the origin css in the iteration
cgroup: always use cgroup_css()
cgroup: rename cgroup_subsys_state->dput_work and its callback function
cgroup: add cgroup_subsys_state->parent
cgroup: cgroup_css_from_dir() now should be called with RCU read locked
cgroup: make cgroup_file_open() rcu_read_lock() around cgroup_css() and add cfent->css
cgroup: add __rcu modifier to cgroup->subsys[]
cgroup: reorganize css init / exit paths
cgroup: move cgroup->subsys[] assignment to online_css()
cgroup: bounce cgroup_subsys_state ref kill confirmation to a work item
cgroup: replace cgroup->css_kill_cnt with ->nr_css
cgroup: decouple cgroup_subsys_state destruction from cgroup destruction
cgroup: factor out kill_css()
cgroup: move subsys file removal to kill_css()
cgroup: RCU protect each cgroup_subsys_state release
cgroup: fix subsystem file accesses on the root cgroup
cgroup: fix cgroup_write_event_control()
cgroup: rename cgroup_css_from_dir() to css_from_dir() and update its syntax
cgroup: make cgroup_css() take cgroup_subsys * instead and allow NULL subsys
cgroup: implement CFTYPE_NO_PREFIX
cgroup: make cgroup_event hold onto cgroup_subsys_state instead of cgroup
cgroup: make cgroup_write_event_control() use css_from_dir() instead of __d_cgrp()
cgroup: fix cgroup_css() invocation in css_from_id()
Zhao Hongjiang (2):
cpuset: get rid of the useless forward declaration of cpuset
cpuset: relocate a misplaced comment
block/blk-cgroup.c | 49 -
block/blk-cgroup.h | 38
block/blk-throttle.c | 43 -
block/cfq-iosched.c | 90 +-
fs/bio.c | 2
include/linux/cgroup.h | 303 ++++---
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 | 1643 ++++++++++++++++++++++++-------------------
kernel/cgroup_freezer.c | 155 ++--
kernel/cpuset.c | 317 ++++----
kernel/events/core.c | 27
kernel/sched/core.c | 113 +-
kernel/sched/cpuacct.c | 51 -
kernel/sched/sched.h | 6
mm/hugetlb_cgroup.c | 69 -
mm/memcontrol.c | 223 ++---
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 | 65 -
24 files changed, 1751 insertions(+), 1611 deletions(-)
--
tejun
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