[PATCH] fix memory less node allocation

[PATCH] fix memory less node allocation

[Bob Picco]

Tony:

The original memory less node allocation attempted to use NODEDATA_ALIGN for
alignment.  The bootmem allocator only allows a power of two alignments. This
causes a BUG_ON for some nodes. For cpu only nodes just allocate with a
PERCPU_PAGE_SIZE alignment.

Some older firmware reports SLIT distances of 0xff and results in bestnode
not being computed. This is now treated correctly.

The failed allocation check was removed because it's redundant.  The
bootmem allocator already makes this check.

This fix has been boot tested on 4 node machine which has 4 cpu only nodes
and 1 memory node.  Thanks to Pete Keilty for reporting this and helping me
test it.  

thanks,

bob

Signed-off-by: Bob Picco <bob.picco@hp.com>

 arch/ia64/mm/discontig.c |   19 +++++++++----------
 1 files changed, 9 insertions(+), 10 deletions(-)

Index: linux-2.6.14-rc3/arch/ia64/mm/discontig.c
=================================--- linux-2.6.14-rc3.orig/arch/ia64/mm/discontig.c	2005-10-26 17:44:36.000000000 -0400
+++ linux-2.6.14-rc3/arch/ia64/mm/discontig.c	2005-10-27 16:44:29.000000000 -0400
@@ -350,14 +350,12 @@ static void __init initialize_pernode_da
  *	for best.
  * @nid: node id
  * @pernodesize: size of this node's pernode data
- * @align: alignment to use for this node's pernode data
  */
-static void __init *memory_less_node_alloc(int nid, unsigned long pernodesize,
-	unsigned long align)
+static void __init *memory_less_node_alloc(int nid, unsigned long pernodesize)
 {
 	void *ptr = NULL;
 	u8 best = 0xff;
-	int bestnode = -1, node;
+	int bestnode = -1, node, anynode = 0;
 
 	for_each_online_node(node) {
 		if (node_isset(node, memory_less_mask))
@@ -366,13 +364,15 @@ static void __init *memory_less_node_all
 			best = node_distance(nid, node);
 			bestnode = node;
 		}
+		anynode = node;
 	}
 
-	ptr = __alloc_bootmem_node(mem_data[bestnode].pgdat,
-		pernodesize, align, __pa(MAX_DMA_ADDRESS));
+	if (bestnode = -1)
+		bestnode = anynode;
+
+	ptr = __alloc_bootmem_node(mem_data[bestnode].pgdat, pernodesize,
+		PERCPU_PAGE_SIZE, __pa(MAX_DMA_ADDRESS));
 
-	if (!ptr)
-		panic("NO memory for memory less node\n");
 	return ptr;
 }
 
@@ -413,8 +413,7 @@ static void __init memory_less_nodes(voi
 
 	for_each_node_mask(node, memory_less_mask) {
 		pernodesize = compute_pernodesize(node);
-		pernode = memory_less_node_alloc(node, pernodesize,
-			(node) ? (node * PERCPU_PAGE_SIZE) : (1024*1024));
+		pernode = memory_less_node_alloc(node, pernodesize);
 		fill_pernode(node, __pa(pernode), pernodesize);
 	}
 

RE: [PATCH] fix memory less node allocation

[Luck, Tony]

-	if (!ptr)
-		panic("NO memory for memory less node\n");

Why did you drop this panic?  Although your patch now
makes sure to never try to alloc from a memory less
node ... surely it is still possible (though unlikely)
that the call to __alloc_bootmem_node() might fail. A
panic here might be easier to debug than letting it run
until fill_pernode() does a memset(__va(0), 0, ...).

-Tony

Re: [PATCH] fix memory less node allocation

[Bob Picco]

luck wrote:	[Thu Nov 03 2005, 05:33:53PM EST]
> -	if (!ptr)
> -		panic("NO memory for memory less node\n");
> 
> Why did you drop this panic?  Although your patch now
> makes sure to never try to alloc from a memory less
> node ... surely it is still possible (though unlikely)
> that the call to __alloc_bootmem_node() might fail. A
> panic here might be easier to debug than letting it run
> until fill_pernode() does a memset(__va(0), 0, ...).
> 
> -Tony
I dropped it because it seemed redundant. __alloc_bootmem_node calls 
__alloc_bootmem_node_limit who calls __alloc_bootmem_core for this
node. Should __alloc_bootmem_core core fail, then call __alloc_bootmem_limit.
__alloc_bootmem_limit attempts to allocate from any node. Should 
__alloc_bootmem_limit (old name __alloc_bootmem)  fail, then it panics.

bob