linux/net/core
Tejun Heo 8c7f6edbda cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them
Currently, cgroup hierarchy support is a mess.  cpu related subsystems
behave correctly - configuration, accounting and control on a parent
properly cover its children.  blkio and freezer completely ignore
hierarchy and treat all cgroups as if they're directly under the root
cgroup.  Others show yet different behaviors.

These differing interpretations of cgroup hierarchy make using cgroup
confusing and it impossible to co-mount controllers into the same
hierarchy and obtain sane behavior.

Eventually, we want full hierarchy support from all subsystems and
probably a unified hierarchy.  Users using separate hierarchies
expecting completely different behaviors depending on the mounted
subsystem is deterimental to making any progress on this front.

This patch adds cgroup_subsys.broken_hierarchy and sets it to %true
for controllers which are lacking in hierarchy support.  The goal of
this patch is two-fold.

* Move users away from using hierarchy on currently non-hierarchical
  subsystems, so that implementing proper hierarchy support on those
  doesn't surprise them.

* Keep track of which controllers are broken how and nudge the
  subsystems to implement proper hierarchy support.

For now, start with a single warning message.  We can whine louder
later on.

v2: Fixed a typo spotted by Michal. Warning message updated.

v3: Updated memcg part so that it doesn't generate warning in the
    cases where .use_hierarchy=false doesn't make the behavior
    different from root.use_hierarchy=true.  Fixed a typo spotted by
    Glauber.

v4: Check ->broken_hierarchy after cgroup creation is complete so that
    ->create() can affect the result per Michal.  Dropped unnecessary
    memcg root handling per Michal.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Li Zefan <lizefan@huawei.com>
Acked-by: Serge E. Hallyn <serue@us.ibm.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Turner <pjt@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2012-09-14 12:01:16 -07:00
..
datagram.c net: skb_free_datagram_locked() doesnt drop all packets 2012-06-27 15:40:57 -07:00
dev_addr_lists.c net: addr_list: add exclusive dev_uc_add and dev_mc_add 2012-04-15 13:06:04 -04:00
dev.c net/core/dev.c: fix kernel-doc warning 2012-08-20 03:00:55 -07:00
drop_monitor.c drop_monitor: dont sleep in atomic context 2012-06-04 11:42:01 -04:00
dst.c net: force dst_default_metrics to const section 2012-08-08 16:00:28 -07:00
ethtool.c ethtool: Make more commands available to unprivileged processes 2012-06-12 18:51:09 -07:00
fib_rules.c ipv4: Elide fib_validate_source() completely when possible. 2012-06-29 01:36:36 -07:00
filter.c netvm: allow skb allocation to use PFMEMALLOC reserves 2012-07-31 18:42:46 -07:00
flow_dissector.c ipv6: add ipv6_addr_hash() helper 2012-07-18 11:28:46 -07:00
flow.c net: Add a flow_cache_flush_deferred function 2011-12-21 16:48:08 -05:00
gen_estimator.c Remove all #inclusions of asm/system.h 2012-03-28 18:30:03 +01:00
gen_stats.c gen_stats: Stop using NLA_PUT*(). 2012-04-02 04:33:44 -04:00
iovec.c net: get rid of some pointless casts to sockaddr 2012-03-11 19:11:22 -07:00
link_watch.c net: linkwatch: allow vlans to get carrier changes faster 2011-09-15 15:36:34 -04:00
Makefile sock_diag: Move the sock_ code to net/core/ 2011-12-06 13:58:02 -05:00
neighbour.c neigh: Convert over to dst_neigh_lookup_skb(). 2012-07-05 01:12:00 -07:00
net_namespace.c net: Statically initialize init_net.dev_base_head 2012-07-18 13:32:27 -07:00
net-sysfs.c wireless: remove wext sysfs 2012-06-05 15:32:15 -04:00
net-sysfs.h xps: Add CONFIG_XPS 2010-11-28 18:24:14 -08:00
net-traces.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
netevent.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
netpoll.c netpoll: revert 6bdb7fe310 and fix be_poll() instead 2012-08-29 15:03:23 -04:00
netprio_cgroup.c cgroup: mark subsystems with broken hierarchy support and whine if cgroups are nested for them 2012-09-14 12:01:16 -07:00
pktgen.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2012-05-20 21:53:04 -04:00
request_sock.c ipv4:correct description for tcp_max_syn_backlog 2011-12-06 13:02:28 -05:00
rtnetlink.c This patch series contains a major revamp of how we collect entropy 2012-07-31 19:07:42 -07:00
scm.c net: netprio: fd passed in SCM_RIGHTS datagram not set correctly 2012-08-16 14:56:11 -07:00
secure_seq.c net: fix some sparse errors 2012-01-17 10:31:12 -05:00
skbuff.c netvm: allow skb allocation to use PFMEMALLOC reserves 2012-07-31 18:42:46 -07:00
sock_diag.c net: make sock diag per-namespace 2012-07-16 22:31:34 -07:00
sock.c tcp: Apply device TSO segment limit earlier 2012-08-02 00:19:17 -07:00
stream.c net: Fix the condition passed to sk_wait_event() 2010-10-03 20:41:32 -07:00
sysctl_net_core.c net: Delete all remaining instances of ctl_path 2012-04-20 21:22:30 -04:00
timestamping.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
user_dma.c net: Add export.h for EXPORT_SYMBOL/THIS_MODULE to non-modules 2011-10-31 19:30:30 -04:00
utils.c net: Fixed coding style issues relating to braces. 2012-04-12 16:35:48 -04:00