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3rd chunk of `content/manuals/engine/containers/resource_constraints.md`
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| `--kernel-memory`      | The maximum amount of kernel memory the container can use. The minimum allowed value is `6m`. Because kernel memory can't be swapped out, a container which is starved of kernel memory may block host machine resources, which can have side effects on the host machine and on other containers. See [`--kernel-memory` details](#--kernel-memory-details).                                   |
| `--oom-kill-disable`   | By default, if an out-of-memory (OOM) error occurs, the kernel kills processes in a container. To change this behavior, use the `--oom-kill-disable` option. Only disable the OOM killer on containers where you have also set the `-m/--memory` option. If the `-m` flag isn't set, the host can run out of memory and the kernel may need to kill the host system's processes to free memory. |

For more information about cgroups and memory in general, see the documentation
for [Memory Resource Controller](https://www.kernel.org/doc/Documentation/cgroup-v1/memory.txt).

### `--memory-swap` details

`--memory-swap` is a modifier flag that only has meaning if `--memory` is also
set. Using swap allows the container to write excess memory requirements to disk
when the container has exhausted all the RAM that's available to it. There is a
performance penalty for applications that swap memory to disk often.

Its setting can have complicated effects:

- If `--memory-swap` is set to a positive integer, then both `--memory` and
  `--memory-swap` must be set. `--memory-swap` represents the total amount of
  memory and swap that can be used, and `--memory` controls the amount used by
  non-swap memory. So if `--memory="300m"` and `--memory-swap="1g"`, the
  container can use 300m of memory and 700m (`1g - 300m`) swap.

- If `--memory-swap` is set to `0`, the setting is ignored, and the value is
  treated as unset.

- If `--memory-swap` is set to the same value as `--memory`, and `--memory` is
  set to a positive integer, **the container doesn't have access to swap**.
  See
  [Prevent a container from using swap](#prevent-a-container-from-using-swap).

- If `--memory-swap` is unset, and `--memory` is set, the container can use
  as much swap as the `--memory` setting, if the host container has swap
  memory configured. For instance, if `--memory="300m"` and `--memory-swap` is
  not set, the container can use 600m in total of memory and swap.

- If `--memory-swap` is explicitly set to `-1`, the container is allowed to use
  unlimited swap, up to the amount available on the host system.

- Inside the container, tools like `free` report the host's available swap, not what's available inside the container. Don't rely on the output of `free` or similar tools to determine whether swap is present.

#### Prevent a container from using swap

If `--memory` and `--memory-swap` are set to the same value, this prevents
containers from using any swap. This is because `--memory-swap` is the amount of
combined memory and swap that can be used, while `--memory` is only the amount
of physical memory that can be used.

### `--memory-swappiness` details

- A value of 0 turns off anonymous page swapping.
- A value of 100 sets all anonymous pages as swappable.
- By default, if you don't set `--memory-swappiness`, the value is
  inherited from the host machine.

### `--kernel-memory` details

Kernel memory limits are expressed in terms of the overall memory allocated to
a container. Consider the following scenarios:

- **Unlimited memory, unlimited kernel memory**: This is the default
  behavior.
- **Unlimited memory, limited kernel memory**: This is appropriate when the
  amount of memory needed by all cgroups is greater than the amount of
  memory that actually exists on the host machine. You can configure the
  kernel memory to never go over what's available on the host machine,
  and containers which need more memory need to wait for it.
- **Limited memory, unlimited kernel memory**: The overall memory is
  limited, but the kernel memory isn't.
Title: Docker Memory Swap, Swappiness and Kernel Memory Details
Summary
This section details the `--memory-swap`, `--memory-swappiness`, and `--kernel-memory` options for Docker containers. `--memory-swap` is used in conjunction with `--memory` to control the amount of swap space a container can use, with different values yielding different swap behaviors, including disabling swap entirely. `--memory-swappiness` tunes the percentage of anonymous pages that can be swapped out, with a default value inherited from the host. `--kernel-memory` limits the amount of kernel memory a container can use, impacting resource allocation and potentially preventing excessive host resource usage. The interaction between these options and overall memory limits are explained, offering insights into optimizing container memory management.