cgroup: Keep accurate count of tasks in each css_set

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The reference count in the css_set data structure was used as a
proxy of the number of tasks attached to that css_set. However, that
count is actually not an accurate measure especially with thread mode
support. So a new variable nr_tasks is added to the css_set to keep
track of the actual task count. This new variable is protected by
the css_set_lock. Functions that require the actual task count are
updated to use the new variable.

tj: s/task_count/nr_tasks/ for consistency with cgroup_root->nr_cgrps.
    Refreshed on top of cgroup/for-v4.13 which dropped on
    css_set_populated() -> nr_tasks conversion.

Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

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Waiman Long 2017-06-13 17:18:01 -04:00 • committed by Tejun Heo

parent 63f700aab4

commit 73a7242a06

3 changed files with 14 additions and 5 deletions

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3

include/linux/cgroup-defs.h

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6

kernel/cgroup/cgroup-v1.c

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10

kernel/cgroup/cgroup.c

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