linux-kernel - Re: [PATCH v5 2/4] mm: Provide kernel parameter to allow disabling page init poisoning

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Date:   Tue, 25 Sep 2018 13:26:39 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Alexander Duyck <alexander.h.duyck@...ux.intel.com>,
        linux-mm@...ck.org, akpm@...ux-foundation.org,
        linux-kernel@...r.kernel.org, linux-nvdimm@...ts.01.org
Cc:     pavel.tatashin@...rosoft.com, mhocko@...e.com,
        dave.jiang@...el.com, jglisse@...hat.com, rppt@...ux.vnet.ibm.com,
        dan.j.williams@...el.com, logang@...tatee.com, mingo@...nel.org,
        kirill.shutemov@...ux.intel.com
Subject: Re: [PATCH v5 2/4] mm: Provide kernel parameter to allow disabling
 page init poisoning

On 09/25/2018 01:20 PM, Alexander Duyck wrote:
> +	vm_debug[=options]	[KNL] Available with CONFIG_DEBUG_VM=y.
> +			May slow down system boot speed, especially when
> +			enabled on systems with a large amount of memory.
> +			All options are enabled by default, and this
> +			interface is meant to allow for selectively
> +			enabling or disabling specific virtual memory
> +			debugging features.
> +
> +			Available options are:
> +			  P	Enable page structure init time poisoning
> +			  -	Disable all of the above options

Can we have vm_debug=off for turning things off, please?  That seems to
be pretty standard.

Also, we need to document the defaults.  I think the default is "all
debug options are enabled", but it would be nice to document that.