Re: [RFC PATCH v9 03/13] mm: Add support for eXclusive Page Frame Ownership (XPFO)

[Waiman Long]

On Wed, Apr 03, 2019 at 11:34:04AM -0600, Khalid Aziz wrote:
> diff --git a/Documentation/admin-guide/kernel-parameters.txt
b/Documentation/admin-guide/kernel-parameters.txt

> index 858b6c0b9a15..9b36da94760e 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -2997,6 +2997,12 @@
>
>ÂÂÂÂÂ nox2apicÂÂÂ [X86-64,APIC] Do not enable x2APIC mode.
>
> +ÂÂÂ noxpfoÂÂÂÂÂÂÂ [XPFO] Disable eXclusive Page Frame Ownership (XPFO)
> +ÂÂÂÂÂÂÂÂÂÂÂ when CONFIG_XPFO is on. Physical pages mapped into
> +ÂÂÂÂÂÂÂÂÂÂÂ user applications will also be mapped in the
> +ÂÂÂÂÂÂÂÂÂÂÂ kernel's address space as if CONFIG_XPFO was not
> +ÂÂÂÂÂÂÂÂÂÂÂ enabled.
> +
>ÂÂÂÂÂ cpu0_hotplugÂÂÂ [X86] Turn on CPU0 hotplug feature when
>ÂÂÂÂÂÂÂÂÂÂÂÂÂ CONFIG_BO OTPARAM_HOTPLUG_CPU0 is off.
>ÂÂÂÂÂÂÂÂÂÂÂÂÂ Some features depend on CPU0. Known dependencies are:

Given the big performance impact that XPFO can have. It should be off by
default when configured. Instead, the xpfo option should be used to
enable it.

Cheers,
Longman