Commit Graph

4 Commits

Author SHA1 Message Date
Aristeu Rozanski bd2953ebbb devcg: propagate local changes down the hierarchy
This patch makes exception changes to propagate down in hierarchy respecting
when possible local exceptions.

New exceptions allowing additional access to devices won't be propagated, but
it'll be possible to add an exception to access all of part of the newly
allowed device(s).

New exceptions disallowing access to devices will be propagated down and the
local group's exceptions will be revalidated for the new situation.
Example:
      A
     / \
        B

    group        behavior          exceptions
    A            allow             "b 8:* rwm", "c 116:1 rw"
    B            deny              "c 1:3 rwm", "c 116:2 rwm", "b 3:* rwm"

If a new exception is added to group A:
	# echo "c 116:* r" > A/devices.deny
it'll propagate down and after revalidating B's local exceptions, the exception
"c 116:2 rwm" will be removed.

In case parent's exceptions change and local exceptions are not allowed anymore,
they'll be deleted.

v7:
- do not allow behavior change when the cgroup has children
- update documentation

v6: fixed issues pointed by Serge Hallyn
- only copy parent's exceptions while propagating behavior if the local
  behavior is different
- while propagating exceptions, do not clear and copy parent's: it'd be against
  the premise we don't propagate access to more devices

v5: fixed issues pointed by Serge Hallyn
- updated documentation
- not propagating when an exception is written to devices.allow
- when propagating a new behavior, clean the local exceptions list if they're
  for a different behavior

v4: fixed issues pointed by Tejun Heo
- separated function to walk the tree and collect valid propagation targets

v3: fixed issues pointed by Tejun Heo
- update documentation
- move css_online/css_offline changes to a new patch
- use cgroup_for_each_descendant_pre() instead of own descendant walk
- move exception_copy rework to a separared patch
- move exception_clean rework to a separated patch

v2: fixed issues pointed by Tejun Heo
- instead of keeping the local settings that won't apply anymore, remove them

Cc: Tejun Heo <tj@kernel.org>
Cc: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2013-03-20 07:50:21 -07:00
Jörg Sommer f6e07d3807 Documentation: update cgroupfs mount point
According to commit 676db4af04 ("cgroupfs: create /sys/fs/cgroup to
mount cgroupfs on") the canonical mountpoint for the cgroup filesystem
is /sys/fs/cgroup.  Hence, this should be used in the documentation.

Signed-off-by: Jörg Sommer <joerg@alea.gnuu.de>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-15 21:52:50 -07:00
Chris Samuel caa790ba6c trivial: cgroups: documentation typo and spelling corrections
Minor typo and spelling corrections fixed whilst reading
to learn about cgroups capabilities.

Signed-off-by: Chris Samuel <chris@csamuel.org>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2009-03-30 15:21:58 +02:00
Li Zefan 45ce80fb6b cgroups: consolidate cgroup documents
Move Documentation/cpusets.txt and Documentation/controllers/* to
Documentation/cgroups/

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Paul Menage <menage@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-01-15 16:39:37 -08:00