From: Roman Gushchin <guroan@gmail.com>
To: Tejun Heo <tj@kernel.org>, Oleg Nesterov <oleg@redhat.com>
Cc: kernel-team@fb.com, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org, Roman Gushchin <guro@fb.com>,
Mike Rapoport <rppt@linux.ibm.com>,
linux-doc@vger.kernel.org
Subject: [PATCH v8 7/7] cgroup: document cgroup v2 freezer interface
Date: Tue, 19 Feb 2019 14:02:52 -0800 [thread overview]
Message-ID: <20190219220252.4906-8-guro@fb.com> (raw)
In-Reply-To: <20190219220252.4906-1-guro@fb.com>
Describe cgroup v2 freezer interface in the cgroup v2 admin guide.
Signed-off-by: Roman Gushchin <guro@fb.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: linux-doc@vger.kernel.org
Cc: kernel-team@fb.com
---
Documentation/admin-guide/cgroup-v2.rst | 27 +++++++++++++++++++++++++
1 file changed, 27 insertions(+)
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 61f8bbb0a1b2..78f078ddbe9c 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -864,6 +864,8 @@ All cgroup core files are prefixed with "cgroup."
populated
1 if the cgroup or its descendants contains any live
processes; otherwise, 0.
+ frozen
+ 1 if the cgroup is frozen; otherwise, 0.
cgroup.max.descendants
A read-write single value files. The default is "max".
@@ -897,6 +899,31 @@ All cgroup core files are prefixed with "cgroup."
A dying cgroup can consume system resources not exceeding
limits, which were active at the moment of cgroup deletion.
+ cgroup.freeze
+ A read-write single value file which exists on non-root cgroups.
+ Allowed values are "0" and "1". The default is "0".
+
+ Writing "1" to the file causes freezing of the cgroup and all
+ descendant cgroups. This means that all belonging processes will
+ be stopped and will not run until the cgroup will be explicitly
+ unfrozen. Freezing of the cgroup may take some time; when this action
+ is completed, the "frozen" value in the cgroup.events control file
+ will be updated to "1" and the corresponding notification will be
+ issued.
+
+ A cgroup can be frozen either by its own settings, or by settings
+ of any ancestor cgroups. If any of ancestor cgroups is frozen, the
+ cgroup will remain frozen.
+
+ Processes in the frozen cgroup can be killed by a fatal signal.
+ They also can enter and leave a frozen cgroup: either by an explicit
+ move by a user, or if freezing of the cgroup races with fork().
+ If a process is moved to a frozen cgroup, it stops. If a process is
+ moved out of a frozen cgroup, it becomes running.
+
+ Frozen status of a cgroup doesn't affect any cgroup tree operations:
+ it's possible to delete a frozen (and empty) cgroup, as well as
+ create new sub-cgroups.
Controllers
===========
--
2.20.1
next prev parent reply other threads:[~2019-02-19 22:03 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-19 22:02 [PATCH v8 0/7] freezer for cgroup v2 Roman Gushchin
2019-02-19 22:02 ` [PATCH v8 1/7] cgroup: rename freezer.c into legacy_freezer.c Roman Gushchin
2019-02-19 22:02 ` [PATCH v8 2/7] cgroup: implement __cgroup_task_count() helper Roman Gushchin
2019-02-19 22:02 ` [PATCH v8 3/7] cgroup: protect cgroup->nr_(dying_)descendants by css_set_lock Roman Gushchin
2019-02-19 22:02 ` [PATCH v8 4/7] cgroup: cgroup v2 freezer Roman Gushchin
2019-02-20 14:42 ` Oleg Nesterov
2019-02-20 22:14 ` Roman Gushchin
2019-02-21 16:44 ` Oleg Nesterov
2019-02-19 22:02 ` [PATCH v8 5/7] kselftests: cgroup: don't fail on cg_kill_all() error in cg_destroy() Roman Gushchin
2019-02-19 22:02 ` [PATCH v8 6/7] kselftests: cgroup: add freezer controller self-tests Roman Gushchin
2019-02-19 22:02 ` Roman Gushchin [this message]
2019-02-20 14:37 ` [PATCH v8 0/7] freezer for cgroup v2 Oleg Nesterov
2019-02-20 22:00 ` Roman Gushchin
2019-02-21 16:29 ` Oleg Nesterov
2019-02-21 17:34 ` Tejun Heo
2019-02-22 16:34 ` Oleg Nesterov
2019-02-22 18:17 ` Tejun Heo
2019-02-25 15:57 ` Oleg Nesterov
2019-03-05 17:27 ` Tejun Heo
2019-02-21 22:43 ` Roman Gushchin
2019-02-22 17:04 ` Oleg Nesterov
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