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authorTejun Heo <tj@kernel.org>2017-09-25 08:12:05 -0700
committerTejun Heo <tj@kernel.org>2017-09-25 08:12:05 -0700
commit041cd640b2f3c5607171c59d8712b503659d21f7 (patch)
tree2979112393aefa10e23245ae95f481763280dd6f /kernel/cgroup/Makefile
parentd2cc5ed6949085cfba30ec5228816cf6eb1d02b9 (diff)
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cgroup: Implement cgroup2 basic CPU usage accounting
In cgroup1, while cpuacct isn't actually controlling any resources, it is a separate controller due to combination of two factors - 1. enabling cpu controller has significant side effects, and 2. we have to pick one of the hierarchies to account CPU usages on. cpuacct controller is effectively used to designate a hierarchy to track CPU usages on. cgroup2's unified hierarchy removes the second reason and we can account basic CPU usages by default. While we can use cpuacct for this purpose, both its interface and implementation leave a lot to be desired - it collects and exposes two sources of truth which don't agree with each other and some of the exposed statistics don't make much sense. Also, it propagates all the way up the hierarchy on each accounting event which is unnecessary. This patch adds basic resource accounting mechanism to cgroup2's unified hierarchy and accounts CPU usages using it. * All accountings are done per-cpu and don't propagate immediately. It just bumps the per-cgroup per-cpu counters and links to the parent's updated list if not already on it. * On a read, the per-cpu counters are collected into the global ones and then propagated upwards. Only the per-cpu counters which have changed since the last read are propagated. * CPU usage stats are collected and shown in "cgroup.stat" with "cpu." prefix. Total usage is collected from scheduling events. User/sys breakdown is sourced from tick sampling and adjusted to the usage using cputime_adjust(). This keeps the accounting side hot path O(1) and per-cpu and the read side O(nr_updated_since_last_read). v2: Minor changes and documentation updates as suggested by Waiman and Roman. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Waiman Long <longman@redhat.com> Cc: Roman Gushchin <guro@fb.com>
Diffstat (limited to 'kernel/cgroup/Makefile')
-rw-r--r--kernel/cgroup/Makefile2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/cgroup/Makefile b/kernel/cgroup/Makefile
index ce693ccb8c58..0acee616e06c 100644
--- a/kernel/cgroup/Makefile
+++ b/kernel/cgroup/Makefile
@@ -1,4 +1,4 @@
-obj-y := cgroup.o namespace.o cgroup-v1.o
+obj-y := cgroup.o stat.o namespace.o cgroup-v1.o
obj-$(CONFIG_CGROUP_FREEZER) += freezer.o
obj-$(CONFIG_CGROUP_PIDS) += pids.o