Xen devel - Aug 2009 - [PATCH] x86/numa: fix c/s 20120 (Fix SRAT check for discontig memory)

That change converted the (wrong) assumption of contiguous nodes''
memory to a similarly wrong one of assuming discontiguous memory (i.e.
each node having separate E820 table entries). The code ought to be
able to deal with both, though, and I hope this change makes it so.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

--- 2009-08-24.orig/xen/arch/x86/srat.c	2009-08-28 00:00:00.000000000 +0200
+++ 2009-08-24/xen/arch/x86/srat.c	2009-08-28 12:12:40.000000000 +0200
@@ -249,15 +249,23 @@ static int nodes_cover_memory(void)
 		start = e820.map[i].addr;
 		end = e820.map[i].addr + e820.map[i].size - 1;
 
-		found = 0;
-		for_each_node_mask(j, nodes_parsed) {
-			if (start >= nodes[j].start && end <= nodes[j].end) {
-				found = 1;
-				break;
-			}
-		}
+		do {
+			found = 0;
+			for_each_node_mask(j, nodes_parsed)
+				if (start < nodes[j].end
+				    && end > nodes[j].start) {
+					if (start >= nodes[j].start) {
+						start = nodes[j].end;
+						found = 1;
+					}
+					if (end <= nodes[j].end) {
+						end = nodes[j].start;
+						found = 1;
+					}
+				}
+		} while (found && start < end);
 
-		if (!found) {
+		if (start < end) {
 			printk(KERN_ERR "SRAT: No PXM for e820 range: "
 				"%016Lx - %016Lx\n", start, end);
 			return 0;




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On Fri, 2009-08-28 at 11:27 +0100, Jan Beulich wrote:
> That change converted the (wrong) assumption of contiguous nodes''
> memory to a similarly wrong one of assuming discontiguous memory (i.e.
> each node having separate E820 table entries). The code ought to be
> able to deal with both, though, and I hope this change makes it so.
Ah, of course.  Thanks Jan, I''ll test it out on my end.

Alex


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On Fri, 2009-08-28 at 11:27 +0100, Jan Beulich wrote:
> That change converted the (wrong) assumption of contiguous nodes''
> memory to a similarly wrong one of assuming discontiguous memory (i.e.
> each node having separate E820 table entries). The code ought to be
> able to deal with both, though, and I hope this change makes it so.
> 
> Signed-off-by: Jan Beulich <jbeulich@novell.com>
Works for me.

Acked-by: Alex Williamson <alex.williamson@hp.com>
> --- 2009-08-24.orig/xen/arch/x86/srat.c	2009-08-28 00:00:00.000000000 +0200
> +++ 2009-08-24/xen/arch/x86/srat.c	2009-08-28 12:12:40.000000000 +0200
> @@ -249,15 +249,23 @@ static int nodes_cover_memory(void)
>  		start = e820.map[i].addr;
>  		end = e820.map[i].addr + e820.map[i].size - 1;
>  
> -		found = 0;
> -		for_each_node_mask(j, nodes_parsed) {
> -			if (start >= nodes[j].start && end <= nodes[j].end) {
> -				found = 1;
> -				break;
> -			}
> -		}
> +		do {
> +			found = 0;
> +			for_each_node_mask(j, nodes_parsed)
> +				if (start < nodes[j].end
> +				    && end > nodes[j].start) {
> +					if (start >= nodes[j].start) {
> +						start = nodes[j].end;
> +						found = 1;
> +					}
> +					if (end <= nodes[j].end) {
> +						end = nodes[j].start;
> +						found = 1;
> +					}
> +				}
> +		} while (found && start < end);
>  
> -		if (!found) {
> +		if (start < end) {
>  			printk(KERN_ERR "SRAT: No PXM for e820 range: "
>  				"%016Lx - %016Lx\n", start, end);
>  			return 0;
> 
> 
> 


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