Add the memory swappiness tuning option to docker.

Memory swappiness option takes 0-100, and helps to tune swappiness
behavior per container.
For example, When a lower value of swappiness is chosen
the container will see minimum major faults. When no value is
specified for memory-swappiness in docker UI, it is inherited from
parent cgroup. (generally 60 unless it is changed).

Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Upstream-commit: b553af956f
Component: cli

components/cli/docs/reference/commandline/create.md

@@ -57,6 +57,7 @@ Creates a new container.
       --privileged=false         Give extended privileges to this container
       --read-only=false          Mount the container's root filesystem as read only
       --restart="no"             Restart policy (no, on-failure[:max-retry], always)
+      --memory-swappiness=""     Tune a container's memory swappiness behavior. Accepts an integer between 0 and 100.
       --security-opt=[]          Security options
       -t, --tty=false            Allocate a pseudo-TTY
       -u, --user=""              Username or UID

components/cli/docs/reference/commandline/run.md

@@ -58,6 +58,7 @@ weight=1
       --read-only=false          Mount the container's root filesystem as read only
       --restart="no"             Restart policy (no, on-failure[:max-retry], always)
       --rm=false                 Automatically remove the container when it exits
+      --memory-swappiness=""     Tune a container's memory swappiness behavior. Accepts an integer between 0 and 100.
       --security-opt=[]          Security Options
       --sig-proxy=true           Proxy received signals to the process
       -t, --tty=false            Allocate a pseudo-TTY

components/cli/docs/reference/run.md

@@ -514,6 +514,7 @@ container:
     --cpu-quota=0: Limit the CPU CFS (Completely Fair Scheduler) quota
     --blkio-weight=0: Block IO weight (relative weight) accepts a weight value between 10 and 1000.
     --oom-kill-disable=true|false: Whether to disable OOM Killer for the container or not.
+    --memory-swappiness="": Tune a container's memory swappiness behavior. Accepts an integer between 0 and 100.
 
 ### Memory constraints
 
@@ -611,6 +612,20 @@ The following example, illustrates a dangerous way to use the flag:
 The container has unlimited memory which can cause the host to run out memory
 and require killing system processes to free memory.
 
+### Swappiness constraint
+
+By default, a container's kernel can swap out a percentage of anonymous pages.
+To set this percentage for a container, specify a `--memory-swappiness` value
+between 0 and 100. A value of 0 turns off anonymous page swapping. A value of
+100 sets all anonymous pages as swappable.
+
+For example, you can set:
+
+    $ docker run -ti --memory-swappiness=0 ubuntu:14.04 /bin/bash
+
+Setting the `--memory-swappiness` option is helpful when you want to retain the
+container's working set and to avoid swapping performance penalties.
+
 ### CPU share constraint
 
 By default, all containers get the same proportion of CPU cycles. This proportion