On Wed, 21 Mar 2007, Christoph Lameter wrote:
> None of that please. The page flags already contain a node number that is
> accessible via page_to_nid(). Just make sure that we never put a slab onto
> the wrong node.
Oh well, here's a patch to find out. (I don't have a NUMA box.)
Pekka
From: Pekka Enberg <[EMAIL PROTECTED]>
This adds a virt_to_nodeid() for looking up the NUMA node ID for a
slab object. The current implementation uses slab->nodeid but adds a
WARN_ON to catch cases where page nid differs. Eventually, we can
change virt_to_nodeid() to use page_to_nid after which slab->nodeid
can be removed.
Signed-off-by: Pekka Enberg <[EMAIL PROTECTED]>
---
mm/slab.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
Index: 2.6/mm/slab.c
===================================================================
--- 2.6.orig/mm/slab.c 2007-03-21 16:58:53.000000000 +0200
+++ 2.6/mm/slab.c 2007-03-21 16:59:26.000000000 +0200
@@ -623,6 +623,14 @@ static inline struct slab *virt_to_slab(
return page_get_slab(page);
}
+static inline unsigned short virt_to_nodeid(const void *obj)
+{
+ struct page *page = virt_to_page(obj);
+ struct slab *slab = page_get_slab(page);
+ WARN_ON(slab->nodeid != page_to_nid(page));
+ return slab->nodeid;
+}
+
static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
unsigned int idx)
{
@@ -1134,8 +1142,7 @@ int i = 0;
static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
{
- struct slab *slabp = virt_to_slab(objp);
- int nodeid = slabp->nodeid;
+ int nodeid = virt_to_nodeid(objp);
struct kmem_list3 *l3;
struct array_cache *alien = NULL;
int node;
@@ -1146,7 +1153,7 @@ static inline int cache_free_alien(struc
* Make sure we are not freeing a object from another node to the array
* cache on this cpu.
*/
- if (likely(slabp->nodeid == node) || unlikely(!use_alien_caches))
+ if (likely(nodeid == node) || unlikely(!use_alien_caches))
return 0;
l3 = cachep->nodelists[node];
@@ -2665,7 +2672,7 @@ static void *slab_get_obj(struct kmem_ca
next = slab_bufctl(slabp)[slabp->free];
#if DEBUG
slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
- WARN_ON(slabp->nodeid != nodeid);
+ WARN_ON(virt_to_nodeid(objp) != nodeid);
#endif
slabp->free = next;
@@ -2679,7 +2686,7 @@ static void slab_put_obj(struct kmem_cac
#if DEBUG
/* Verify that the slab belongs to the intended node */
- WARN_ON(slabp->nodeid != nodeid);
+ WARN_ON(virt_to_nodeid(objp) != nodeid);
if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) {
printk(KERN_ERR "slab: double free detected in cache "
-
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