Re: [PATCH 1/3] x86/xen: don't count how many PFNs are identity mapped

[Juergen Gross <jgross@suse.com>]

On 01/07/2015 03:47 PM, David Vrabel wrote:
> This accounting is just used to print a diagnostic message that isn't
> very useful.
>
> Signed-off-by: David Vrabel <david.vrabel@citrix.com>

Reviewed-by: Juergen Gross <jgross@suse.com>

> ---
>   arch/x86/xen/setup.c |   27 +++++++++------------------
>   1 file changed, 9 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> index dfd77de..664dffc 100644
> --- a/arch/x86/xen/setup.c
> +++ b/arch/x86/xen/setup.c
> @@ -229,15 +229,14 @@ static int __init xen_free_mfn(unsigned long mfn)
>    * as a fallback if the remapping fails.
>    */
>   static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn,
> -	unsigned long end_pfn, unsigned long nr_pages, unsigned long *identity,
> -	unsigned long *released)
> +	unsigned long end_pfn, unsigned long nr_pages, unsigned long *released)
>   {
> -	unsigned long len = 0;
>   	unsigned long pfn, end;
>   	int ret;
>
>   	WARN_ON(start_pfn > end_pfn);
>
> +	/* Release pages first. */
>   	end = min(end_pfn, nr_pages);
>   	for (pfn = start_pfn; pfn < end; pfn++) {
>   		unsigned long mfn = pfn_to_mfn(pfn);
> @@ -250,16 +249,14 @@ static void __init xen_set_identity_and_release_chunk(unsigned long start_pfn,
>   		WARN(ret != 1, "Failed to release pfn %lx err=%d\n", pfn, ret);
>
>   		if (ret == 1) {
> +			(*released)++;
>   			if (!__set_phys_to_machine(pfn, INVALID_P2M_ENTRY))
>   				break;
> -			len++;
>   		} else
>   			break;
>   	}
>
> -	/* Need to release pages first */
> -	*released += len;
> -	*identity += set_phys_range_identity(start_pfn, end_pfn);
> +	set_phys_range_identity(start_pfn, end_pfn);
>   }
>
>   /*
> @@ -318,7 +315,6 @@ static void __init xen_do_set_identity_and_remap_chunk(
>   	unsigned long ident_pfn_iter, remap_pfn_iter;
>   	unsigned long ident_end_pfn = start_pfn + size;
>   	unsigned long left = size;
> -	unsigned long ident_cnt = 0;
>   	unsigned int i, chunk;
>
>   	WARN_ON(size == 0);
> @@ -347,8 +343,7 @@ static void __init xen_do_set_identity_and_remap_chunk(
>   		xen_remap_mfn = mfn;
>
>   		/* Set identity map */
> -		ident_cnt += set_phys_range_identity(ident_pfn_iter,
> -			ident_pfn_iter + chunk);
> +		set_phys_range_identity(ident_pfn_iter, ident_pfn_iter + chunk);
>
>   		left -= chunk;
>   	}
> @@ -371,7 +366,7 @@ static void __init xen_do_set_identity_and_remap_chunk(
>   static unsigned long __init xen_set_identity_and_remap_chunk(
>           const struct e820entry *list, size_t map_size, unsigned long start_pfn,
>   	unsigned long end_pfn, unsigned long nr_pages, unsigned long remap_pfn,
> -	unsigned long *identity, unsigned long *released)
> +	unsigned long *released)
>   {
>   	unsigned long pfn;
>   	unsigned long i = 0;
> @@ -386,8 +381,7 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
>   		/* Do not remap pages beyond the current allocation */
>   		if (cur_pfn >= nr_pages) {
>   			/* Identity map remaining pages */
> -			*identity += set_phys_range_identity(cur_pfn,
> -				cur_pfn + size);
> +			set_phys_range_identity(cur_pfn, cur_pfn + size);
>   			break;
>   		}
>   		if (cur_pfn + size > nr_pages)
> @@ -398,7 +392,7 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
>   		if (!remap_range_size) {
>   			pr_warning("Unable to find available pfn range, not remapping identity pages\n");
>   			xen_set_identity_and_release_chunk(cur_pfn,
> -				cur_pfn + left, nr_pages, identity, released);
> +				cur_pfn + left, nr_pages, released);
>   			break;
>   		}
>   		/* Adjust size to fit in current e820 RAM region */
> @@ -410,7 +404,6 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
>   		/* Update variables to reflect new mappings. */
>   		i += size;
>   		remap_pfn += size;
> -		*identity += size;
>   	}
>
>   	/*
> @@ -430,7 +423,6 @@ static void __init xen_set_identity_and_remap(
>   	unsigned long *released)
>   {
>   	phys_addr_t start = 0;
> -	unsigned long identity = 0;
>   	unsigned long last_pfn = nr_pages;
>   	const struct e820entry *entry;
>   	unsigned long num_released = 0;
> @@ -460,14 +452,13 @@ static void __init xen_set_identity_and_remap(
>   				last_pfn = xen_set_identity_and_remap_chunk(
>   						list, map_size, start_pfn,
>   						end_pfn, nr_pages, last_pfn,
> -						&identity, &num_released);
> +						&num_released);
>   			start = end;
>   		}
>   	}
>
>   	*released = num_released;
>
> -	pr_info("Set %ld page(s) to 1-1 mapping\n", identity);
>   	pr_info("Released %ld page(s)\n", num_released);
>   }
>
>