From: Roman Gushchin <guroan@gmail.com>
To: Tejun Heo <tj@kernel.org>, Oleg Nesterov <oleg@redhat.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
cgroups@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel-team@fb.com,
Roman Gushchin <guro@fb.com>
Subject: [PATCH v5 7/7] cgroup: document cgroup v2 freezer interface
Date: Fri, 7 Dec 2018 12:15:31 -0800 [thread overview]
Message-ID: <20181207201531.1665-8-guro@fb.com> (raw)
In-Reply-To: <20181207201531.1665-1-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 07e06136a550..f8335e26b362 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
===========
--
2.17.2
prev parent reply other threads:[~2018-12-07 20:15 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-07 20:15 [PATCH v5 0/7] freezer for cgroup v2 Roman Gushchin
2018-12-07 20:15 ` [PATCH v5 1/7] cgroup: rename freezer.c into legacy_freezer.c Roman Gushchin
2018-12-07 20:15 ` [PATCH v5 2/7] cgroup: implement __cgroup_task_count() helper Roman Gushchin
2018-12-07 20:15 ` [PATCH v5 3/7] cgroup: protect cgroup->nr_(dying_)descendants by css_set_lock Roman Gushchin
2018-12-07 20:15 ` [PATCH v5 4/7] cgroup: cgroup v2 freezer Roman Gushchin
2018-12-11 16:26 ` Oleg Nesterov
2018-12-11 18:40 ` Roman Gushchin
2018-12-12 17:49 ` Oleg Nesterov
2018-12-18 1:28 ` Roman Gushchin
2018-12-18 17:12 ` Oleg Nesterov
2018-12-18 20:27 ` Roman Gushchin
2018-12-20 16:16 ` Oleg Nesterov
2018-12-20 21:43 ` Roman Gushchin
2018-12-07 20:15 ` [PATCH v5 5/7] kselftests: cgroup: don't fail on cg_kill_all() error in cg_destroy() Roman Gushchin
2018-12-07 20:15 ` [PATCH v5 6/7] kselftests: cgroup: add freezer controller self-tests Roman Gushchin
2018-12-07 20:15 ` Roman Gushchin [this message]
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