config-linux: Move 'disableOOMKiller' under 'memory'

It's backed by memory.oom_control, so this commit moves it in with
the rest of the memory-controller config.

Looking at the history, the initial request landing a setting for this
in the Docker/OCI ecosystem seems to be [1], which added
Cgroup.OomKillDisable.  That commit was carried from libcontainer into
runC [2] where it is now Resources.OomKillDisable [3].  From runC it
was carried into this repo (with some renaming) in [4].  Subsequent
early doc updates landed in [5,6].  In none of those can I find
discussion about why the setting is not already under memory.  I
expect the reason is that the runC structures are flat, so "under
memory" is not a thing there.  But in this spec, resources has
per-controller sub-properties.  The fact that disableOOMKiller
belonged to the memory controller may have been overlooked in [4] and
never revisited until now.

[1]: docker-archive/libcontainer#417
     Subject: cgroups: add support for oom control
[2]: opencontainers/runc@295c708
     Subject: cgroups: add support for oom control
[3]: https://github.com/opencontainers/runc/blob/v1.0.0-rc3/libcontainer/configs/cgroup_unix.go#L113-L114
[4]: opencontainers#51
     Subject: Add Go types for specification
[5]: opencontainers#137
     Subject: Adding cgroups path to the Spec.
[6]: opencontainers#199
     Subject: runtime: config: linux: add cgroups informations

Signed-off-by: W. Trevor King <[email protected]>

Author: wking

config-linux.md

@@ -253,22 +253,6 @@ Each entry has the following structure:
     ]
 ```
 
-### <a name="configLinuxDisableOutOfMemoryKiller" />Disable out-of-memory killer
-
-`disableOOMKiller` contains a boolean (`true` or `false`) that enables or disables the Out of Memory killer for a cgroup.
-If enabled (`false`), tasks that attempt to consume more memory than they are allowed are immediately killed by the OOM killer.
-The OOM killer is enabled by default in every cgroup using the `memory` subsystem.
-To disable it, specify a value of `true`.
-For more information, see the kernel cgroups documentation about [memory][cgroup-v1-memory].
-
-* **`disableOOMKiller`** *(bool, OPTIONAL)* - enables or disables the OOM killer
-
-#### Example
-
-```json
-    "disableOOMKiller": false
-```
-
 ### <a name="configLinuxMemory" />Memory
 
 **`memory`** (object, OPTIONAL) represents the cgroup subsystem `memory` and it's used to set limits on the container's memory usage.
@@ -282,9 +266,14 @@ Values for memory specify the limit in bytes, or `-1` for unlimited memory.
 * **`kernel`** *(int64, OPTIONAL)* - sets hard limit for kernel memory
 * **`kernelTCP`** *(int64, OPTIONAL)* - sets hard limit for kernel TCP buffer memory
 
-For `swappiness` the values are from 0 to 100. Higher means more swappy.
+The following properties do not specify memory limits, but are covered by the `memory` controller:
 
 * **`swappiness`** *(uint64, OPTIONAL)* - sets swappiness parameter of vmscan (See sysctl's vm.swappiness)
+    The values are from 0 to 100. Higher means more swappy.
+* **`disableOOMKiller`** *(bool, OPTIONAL)* - enables or disables the OOM killer.
+    If enabled (`false`), tasks that attempt to consume more memory than they are allowed are immediately killed by the OOM killer.
+    The OOM killer is enabled by default in every cgroup using the `memory` subsystem.
+    To disable it, specify a value of `true`.
 
 #### Example
 
@@ -295,7 +284,8 @@ For `swappiness` the values are from 0 to 100. Higher means more swappy.
         "swap": 536870912,
         "kernel": -1,
         "kernelTCP": -1,
-        "swappiness": 0
+        "swappiness": 0,
+        "disableOOMKiller": false
     }
 ```
 

config.md

@@ -202,7 +202,7 @@ For Linux-based systems, the `process` object supports the following process-spe
     If `oomScoreAdj` is set, the runtime MUST set `oom_score_adj` to the given value.
     If `oomScoreAdj` is not set, the runtime MUST NOT change the value of `oom_score_adj`.
 
-    This is a per-process setting, where as [`disableOOMKiller`](config-linux.md#disable-out-of-memory-killer) is scoped for a memory cgroup.
+    This is a per-process setting, where as [`disableOOMKiller`](config-linux.md#memory) is scoped for a memory cgroup.
     For more information on how these two settings work together, see [the memory cgroup documentation section 10. OOM Contol][cgroup-v1-memory_2].
 * **`selinuxLabel`** (string, OPTIONAL) specifies the SELinux label for the process.
     For more information about SELinux, see  [SELinux documentation][selinux].
@@ -710,7 +710,8 @@ Here is a full example `config.json` for reference.
                 "swap": 536870912,
                 "kernel": -1,
                 "kernelTCP": -1,
-                "swappiness": 0
+                "swappiness": 0,
+                "disableOOMKiller": false
             },
             "cpu": {
                 "shares": 1024,
@@ -721,7 +722,6 @@ Here is a full example `config.json` for reference.
                 "cpus": "2-3",
                 "mems": "0-7"
             },
-            "disableOOMKiller": false,
             "devices": [
                 {
                     "allow": false,

schema/config-linux.json

@@ -143,10 +143,6 @@
                             }
                         }
                     },
-                    "disableOOMKiller": {
-                        "id": "https://opencontainers.org/schema/bundle/linux/resources/disableOOMKiller",
-                        "type": "boolean"
-                    },
                     "hugepageLimits": {
                         "id": "https://opencontainers.org/schema/bundle/linux/resources/hugepageLimits",
                         "type": "array",
@@ -193,6 +189,10 @@
                             "swappiness": {
                                 "id": "https://opencontainers.org/schema/bundle/linux/resources/memory/swappiness",
                                 "$ref": "defs.json#/definitions/uint64"
+                            },
+                            "disableOOMKiller": {
+                                "id": "https://opencontainers.org/schema/bundle/linux/resources/memory/disableOOMKiller",
+                                "type": "boolean"
                             }
                         }
                     },

schema/test/config/good/spec-example.json

@@ -241,7 +241,8 @@
                 "swap": 536870912,
                 "kernel": -1,
                 "kernelTCP": -1,
-                "swappiness": 0
+                "swappiness": 0,
+                "disableOOMKiller": false
             },
             "cpu": {
                 "shares": 1024,
@@ -252,7 +253,6 @@
                 "cpus": "2-3",
                 "mems": "0-7"
             },
-            "disableOOMKiller": false,
             "devices": [
                 {
                     "allow": false,

specs-go/config.go

@@ -284,6 +284,8 @@ type LinuxMemory struct {
 	KernelTCP *int64 `json:"kernelTCP,omitempty"`
 	// How aggressive the kernel will swap memory pages.
 	Swappiness *uint64 `json:"swappiness,omitempty"`
+	// DisableOOMKiller disables the OOM killer for out of memory conditions
+	DisableOOMKiller *bool `json:"disableOOMKiller,omitempty"`
 }
 
 // LinuxCPU for Linux cgroup 'cpu' resource management
@@ -322,8 +324,6 @@ type LinuxNetwork struct {
 type LinuxResources struct {
 	// Devices configures the device whitelist.
 	Devices []LinuxDeviceCgroup `json:"devices,omitempty"`
-	// DisableOOMKiller disables the OOM killer for out of memory conditions
-	DisableOOMKiller *bool `json:"disableOOMKiller,omitempty"`
 	// Memory restriction configuration
 	Memory *LinuxMemory `json:"memory,omitempty"`
 	// CPU resource restriction configuration