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From: Roman Gushchin <guroan@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>,
	cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-team@fb.com, Roman Gushchin <guro@fb.com>
Subject: [PATCH] cgroup: document cgroup v2 freezer interface
Date: Mon, 12 Nov 2018 15:04:16 -0800	[thread overview]
Message-ID: <20181112230422.5911-2-guro@fb.com> (raw)
In-Reply-To: <20181112230422.5911-1-guro@fb.com>

Describe cgroup v2 freezer interface in the cgroup v2 admin guide.

Signed-off-by: Roman Gushchin <guro@fb.com>
Cc: Tejun Heo <tj@kernel.org>
---
 Documentation/admin-guide/cgroup-v2.rst | 26 +++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index 184193bcb262..a065c0bed88c 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -862,6 +862,8 @@ 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".
@@ -895,6 +897,30 @@ 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 the process
+	is complete, the "frozen" value in the cgroup.events control file
+	will be updated and the corresponding notification will be issued.
+
+	Cgroup can be frozen either by its own settings, either 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, either if freezing of the cgroup races with fork().
+	If a cgroup is moved to a frozen cgroup, it stops. If a process is
+	moving 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


  reply	other threads:[~2018-11-12 23:04 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-12 23:04 [PATCH v2 0/6] freezer for cgroup v2 Roman Gushchin
2018-11-12 23:04 ` Roman Gushchin [this message]
2018-11-12 23:04 ` [PATCH v2 1/6] cgroup: rename freezer.c into legacy_freezer.c Roman Gushchin
2018-11-12 23:04 ` [PATCH v2 2/6] cgroup: implement __cgroup_task_count() helper Roman Gushchin
2018-11-12 23:04 ` [PATCH v2 3/6] cgroup: cgroup v2 freezer Roman Gushchin
2018-11-13  2:08   ` Tejun Heo
2018-11-13 18:47     ` Roman Gushchin
2018-11-13 19:15       ` Tejun Heo
2018-11-13 20:55         ` Roman Gushchin
2018-11-13 20:58           ` Tejun Heo
2018-11-13 15:37   ` Oleg Nesterov
2018-11-13 15:43     ` Tejun Heo
2018-11-13 16:00       ` Oleg Nesterov
2018-11-13 15:48   ` Oleg Nesterov
2018-11-13 21:59     ` Roman Gushchin
2018-11-14 16:56       ` Oleg Nesterov
2018-11-14 17:06         ` Roman Gushchin
2018-11-14 17:36           ` Oleg Nesterov
2018-11-14 17:39             ` Roman Gushchin
2018-11-28 17:36         ` Roman Gushchin
2018-11-12 23:04 ` [PATCH v2 4/6] kselftests: cgroup: don't fail on cg_kill_all() error in cg_destroy() Roman Gushchin
2018-11-12 23:04 ` [PATCH v2 5/6] kselftests: cgroup: add freezer controller self-tests Roman Gushchin
2018-11-12 23:04 ` [PATCH v2 6/6] cgroup: document cgroup v2 freezer interface Roman Gushchin

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