[PATCH 1/4] x86_64: Fix ACPI NUMA parsing

[PATCH 1/4] x86_64: Fix ACPI NUMA parsing

[Andi Kleen]

Fix SRAT NUMA parsing

Fix fallout from the recent nodemask_t changes. The node ids assigned 
in the SRAT parser were off by one.

I added a new first_unset_node() function to nodemask.h to allocate
IDs sanely.

Signed-off-by: Andi Kleen <ak@suse.de>

Index: linux/arch/x86_64/mm/srat.c
===================================================================
--- linux.orig/arch/x86_64/mm/srat.c	2005-01-09 18:19:17.%N +0100
+++ linux/arch/x86_64/mm/srat.c	2005-01-12 04:15:43.%N +0100
@@ -20,17 +20,20 @@
 
 static struct acpi_table_slit *acpi_slit;
 
-static DECLARE_BITMAP(nodes_parsed, MAX_NUMNODES) __initdata;
+static nodemask_t nodes_parsed __initdata;
+static nodemask_t nodes_found __initdata;
 static struct node nodes[MAX_NUMNODES] __initdata;
 static __u8  pxm2node[256] __initdata = { [0 ... 255] = 0xff };
 
 static __init int setup_node(int pxm)
 {
-	if (pxm2node[pxm] == 0xff) {
-		if (num_online_nodes() >= MAX_NUMNODES)
+	unsigned node = pxm2node[pxm];
+	if (node == 0xff) {
+		if (nodes_weight(nodes_found) >= MAX_NUMNODES)
 			return -1;
-		pxm2node[pxm] = num_online_nodes();
-		node_set_online(num_online_nodes());
+		node = first_unset_node(nodes_found); 
+		node_set(node, nodes_found);
+		pxm2node[pxm] = node;
 	}
 	return pxm2node[pxm];
 }
@@ -140,7 +143,7 @@
 		return;
 	}
 	nd = &nodes[node];
-	if (!test_and_set_bit(node, &nodes_parsed)) {
+	if (!node_test_and_set(node, nodes_parsed)) {
 		nd->start = start;
 		nd->end = end;
 	} else {
@@ -171,7 +174,7 @@
 		return -1;
 	}
 	for (i = 0; i < MAX_NUMNODES; i++) {
-		if (!test_bit(i, &nodes_parsed))
+		if (!node_isset(i, nodes_parsed))
 			continue;
 		cutoff_node(i, start, end);
 		if (nodes[i].start == nodes[i].end)
Index: linux/include/linux/nodemask.h
===================================================================
--- linux.orig/include/linux/nodemask.h	2005-01-12 02:43:49.%N +0100
+++ linux/include/linux/nodemask.h	2005-01-12 04:15:43.%N +0100
@@ -38,6 +38,8 @@
  *
  * int first_node(mask)			Number lowest set bit, or MAX_NUMNODES
  * int next_node(node, mask)		Next node past 'node', or MAX_NUMNODES
+ * int first_unset_node(mask)		First node not set in mask, or 
+ *					MAX_NUMNODES.
  *
  * nodemask_t nodemask_of_node(node)	Return nodemask with bit 'node' set
  * NODE_MASK_ALL			Initializer - all bits set
@@ -238,6 +240,13 @@
 	m;								\
 })
 
+#define first_unset_node(mask) __first_unset_node(&(mask))
+static inline int __first_unset_node(const nodemask_t *maskp)
+{
+	return min_t(int,MAX_NUMNODES,
+			find_first_zero_bit(maskp->bits, MAX_NUMNODES));
+}
+
 #define NODE_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(MAX_NUMNODES)
 
 #if MAX_NUMNODES <= BITS_PER_LONG

Re: [PATCH 1/4] x86_64: Fix ACPI NUMA parsing

[Matthew Dobson]

On Tue, 2005-01-11 at 23:01, Andi Kleen wrote:
> Fix SRAT NUMA parsing
> 
> Fix fallout from the recent nodemask_t changes. The node ids assigned 
> in the SRAT parser were off by one.
> 
> I added a new first_unset_node() function to nodemask.h to allocate
> IDs sanely.
> 
> Signed-off-by: Andi Kleen <ak@suse.de>
> 
> Index: linux/arch/x86_64/mm/srat.c
> ===================================================================
> --- linux.orig/arch/x86_64/mm/srat.c	2005-01-09 18:19:17.%N +0100
> +++ linux/arch/x86_64/mm/srat.c	2005-01-12 04:15:43.%N +0100
> @@ -20,17 +20,20 @@
>  
>  static struct acpi_table_slit *acpi_slit;
>  
> -static DECLARE_BITMAP(nodes_parsed, MAX_NUMNODES) __initdata;
> +static nodemask_t nodes_parsed __initdata;
> +static nodemask_t nodes_found __initdata;
>  static struct node nodes[MAX_NUMNODES] __initdata;
>  static __u8  pxm2node[256] __initdata = { [0 ... 255] = 0xff };
>  
>  static __init int setup_node(int pxm)
>  {
> -	if (pxm2node[pxm] == 0xff) {
> -		if (num_online_nodes() >= MAX_NUMNODES)
> +	unsigned node = pxm2node[pxm];
> +	if (node == 0xff) {
> +		if (nodes_weight(nodes_found) >= MAX_NUMNODES)
>  			return -1;
> -		pxm2node[pxm] = num_online_nodes();
> -		node_set_online(num_online_nodes());
> +		node = first_unset_node(nodes_found); 
> +		node_set(node, nodes_found);
> +		pxm2node[pxm] = node;
>  	}
>  	return pxm2node[pxm];
>  }

This snippet looks incorrect because first_unset_node() can return
MAX_NUMNODES, which isn't a valid node number, nor is it valid to set a
bit >= MAX_NUMNODES in a nodemask.  Although, this is init code, so
there shouldn't be other CPUs messing with the nodes_found mask at the
same time, and you do check that there are unset bits in nodes_found
before the first_unset_node() call, so I'm probably wrong.  Is there any
reason you don't just do all these checks on node_online_map?  ie:

	if (nodes_weight(node_online_map) >= MAX_NUMNODES)
		return -1;
	node = first_unset_node(node_online_map); 
	node_set(node, nodes_found);
	pxm2node[pxm] = node;

The extra nodes_found bitmask seems unnecessary?  I like the idea of the
first_unset_node() function, though.

-Matt

Re: [PATCH 1/4] x86_64: Fix ACPI NUMA parsing

[Andi Kleen]

On Wed, Jan 12, 2005 at 01:56:49PM -0800, Matthew Dobson wrote:
> On Tue, 2005-01-11 at 23:01, Andi Kleen wrote:
> > Fix SRAT NUMA parsing
> > 
> > Fix fallout from the recent nodemask_t changes. The node ids assigned 
> > in the SRAT parser were off by one.
> > 
> > I added a new first_unset_node() function to nodemask.h to allocate
> > IDs sanely.
> > 
> > Signed-off-by: Andi Kleen <ak@suse.de>
> > 
> > Index: linux/arch/x86_64/mm/srat.c
> > ===================================================================
> > --- linux.orig/arch/x86_64/mm/srat.c	2005-01-09 18:19:17.%N +0100
> > +++ linux/arch/x86_64/mm/srat.c	2005-01-12 04:15:43.%N +0100
> > @@ -20,17 +20,20 @@
> >  
> >  static struct acpi_table_slit *acpi_slit;
> >  
> > -static DECLARE_BITMAP(nodes_parsed, MAX_NUMNODES) __initdata;
> > +static nodemask_t nodes_parsed __initdata;
> > +static nodemask_t nodes_found __initdata;
> >  static struct node nodes[MAX_NUMNODES] __initdata;
> >  static __u8  pxm2node[256] __initdata = { [0 ... 255] = 0xff };
> >  
> >  static __init int setup_node(int pxm)
> >  {
> > -	if (pxm2node[pxm] == 0xff) {
> > -		if (num_online_nodes() >= MAX_NUMNODES)
> > +	unsigned node = pxm2node[pxm];
> > +	if (node == 0xff) {
> > +		if (nodes_weight(nodes_found) >= MAX_NUMNODES)
> >  			return -1;
> > -		pxm2node[pxm] = num_online_nodes();
> > -		node_set_online(num_online_nodes());
> > +		node = first_unset_node(nodes_found); 
> > +		node_set(node, nodes_found);
> > +		pxm2node[pxm] = node;
> >  	}
> >  	return pxm2node[pxm];
> >  }
> 
> This snippet looks incorrect because first_unset_node() can return
> MAX_NUMNODES, which isn't a valid node number, nor is it valid to set a
> bit >= MAX_NUMNODES in a nodemask.  Although, this is init code, so

The nodes_weight check handles this. 

> there shouldn't be other CPUs messing with the nodes_found mask at the
> same time, and you do check that there are unset bits in nodes_found
> before the first_unset_node() call, so I'm probably wrong.  Is there any
> reason you don't just do all these checks on node_online_map?  ie:
> 
> 	if (nodes_weight(node_online_map) >= MAX_NUMNODES)
> 		return -1;
> 	node = first_unset_node(node_online_map); 
> 	node_set(node, nodes_found);
> 	pxm2node[pxm] = node;
> 
> The extra nodes_found bitmask seems unnecessary?  I like the idea of the
> first_unset_node() function, though.

It keeps clean global state in case there is an error and we fall 
back to non NUMA.

-Andi