cgroup_freezer: don't use cgroup_lock_live_group()

Browse source

freezer_read/write() used cgroup_lock_live_group() to synchronize
against task migration into and out of the target cgroup.
cgroup_lock_live_group() grabs the internal cgroup lock and using it
from outside cgroup core leads to complex and fragile locking
dependency issues which are difficult to resolve.

Now that freezer_can_attach() is replaced with freezer_attach() and
update_if_frozen() updated, nothing requires excluding migration
against freezer state reads and changes.

This patch removes cgroup_lock_live_group() and the matching
cgroup_unlock() usages.  The prone-to-bitrot, already outdated and
unnecessary global lock hierarchy documentation is replaced with
documentation in local scope.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Li Zefan <lizefan@huawei.com>

...

This commit is contained in:

Tejun Heo 2012-10-16 15:03:15 -07:00

parent b4d18311d3

commit ead5c47371

1 changed files with 10 additions and 56 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

66

kernel/cgroup_freezer.c

View file