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Subject: Re: [PATCH 2/2] Revert "xen: fix p2m size in dom0 for disabled memory
 hotplug case"
To:     Roger Pau Monne <roger.pau@citrix.com>,
        linux-kernel@vger.kernel.org
Cc:     Juergen Gross <jgross@suse.com>,
        Stefano Stabellini <sstabellini@kernel.org>,
        Jan Beulich <jbeulich@suse.com>, xen-devel@lists.xenproject.org
References: <20210317110401.46322-1-roger.pau@citrix.com>
 <20210317110401.46322-3-roger.pau@citrix.com>
From:   Boris Ostrovsky <boris.ostrovsky@oracle.com>
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On 3/17/21 7:04 AM, Roger Pau Monne wrote:
>  
>  	/*
> -	 * Clamp the amount of extra memory to a XEN_EXTRA_MEM_RATIO
> -	 * factor the base size.
> +	 * Clamp the amount of extra memory to a EXTRA_MEM_RATIO
> +	 * factor the base size.  On non-highmem systems, the base
> +	 * size is the full initial memory allocation; on highmem it
> +	 * is limited to the max size of lowmem, so that it doesn't
> +	 * get completely filled.
>  	 *
>  	 * Make sure we have no memory above max_pages, as this area
>  	 * isn't handled by the p2m management.
> +	 *
> +	 * In principle there could be a problem in lowmem systems if
> +	 * the initial memory is also very large with respect to
> +	 * lowmem, but we won't try to deal with that here.
>  	 */


This comment looks out-of-date in light of deprecated support for 32-bit PV. So I think we don't need to revert this part (except for the macro name).


-boris