cgroup: remove cgroup_enable_task_cg_lists() optimization

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cgroup_enable_task_cg_lists() is used to lazyily initialize task
cgroup associations on the first use to reduce fork / exit overheads
on systems which don't use cgroup.  Unfortunately, locking around it
has never been actually correct and its value is dubious given how the
vast majority of systems use cgroup right away from boot.

This patch removes the optimization.  For now, replace the cg_list
based branches with WARN_ON_ONCE()'s to be on the safe side.  We can
simplify the logic further in the future.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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This commit is contained in:

Tejun Heo 2019-10-24 12:03:51 -07:00

parent a713af394c

commit 5153faac18

3 changed files with 39 additions and 148 deletions

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1

include/linux/cgroup.h

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186

kernel/cgroup/cgroup.c

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2

kernel/cgroup/cpuset.c

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