[PATCH] Fix test/prefered v2

[Andi Kleen <andi@firstfloor.org>]

> Fix test/prefered
> 
> Couple of bugs here:
> 
> - First the kernel errors out of the nodemask is < MAXNUMNODES,
> so have to discover that at runtime. There's no function
> in libnuma for this (perhaps there should be one?), so i
> wrote one here.
> - The loop set the node in the wrong mask, breaking the test

Sorry that was the broken version, here's a v2 with a actually
working max_numnode. The older version happened to work
on my test system, but was obviously not correct.

---

Fix test/prefered v2
 
Couple of bugs here:
 
- First the kernel errors out of the nodemask is < MAXNUMNODES,
so have to discover that at runtime. There's no function
in libnuma for this (perhaps there should be one?), so i
wrote one here.
- The loop set the node in the wrong mask, breaking the test

v2: Correct max_numnode detection

Signed-off-by: Andi Kleen <ak@linux.intel.com>


--- numactl-2.0.2/test/prefered.c	2008-08-05 16:36:58.000000000 +0200
+++ numactl-2.0.2-hack/test/prefered.c	2009-01-10 07:00:16.000000000 +0100
@@ -6,20 +6,38 @@
 #include <assert.h>
 #include <unistd.h>
 #include <stdlib.h>
+#include <errno.h>
 
 #define err(x) perror(x),exit(1)
 
+/* Discover MAXNUMNODE of the kernel */
+int max_numnode(void)
+{	
+	int v;
+	unsigned size = 64;
+	struct bitmask *mask = numa_bitmask_alloc(size);
+	while (get_mempolicy(NULL, mask->maskp, mask->size, &v, MPOL_F_ADDR) < 0 &&
+			errno == EINVAL) {
+		numa_bitmask_free(mask);
+		size <<= 1;
+		mask = numa_bitmask_alloc(size);
+	}
+	numa_bitmask_free(mask);
+	return size;
+}
+
 int main(void)
 {
 	int max = numa_max_node();
+	int maxmask = max_numnode();
 	struct bitmask *nodes, *mask;
 	int pagesize = getpagesize();
 	int i;
 	int pol;
 	int node;
 	int err = 0;
-	nodes = numa_bitmask_alloc(max+1);
-	mask = numa_bitmask_alloc(max+1);
+	nodes = numa_bitmask_alloc(maxmask);
+	mask = numa_bitmask_alloc(maxmask);
 
 	for (i = max; i >= 0; --i) { 
 		char *mem = mmap(NULL, pagesize*(max+1), PROT_READ|PROT_WRITE, 
@@ -33,8 +51,8 @@
 
 		numa_bitmask_clearall(nodes);
 		numa_bitmask_clearall(mask);
-		numa_bitmask_setbit(mask, i);
+		numa_bitmask_setbit(nodes, i);
 
 		if (mbind(adr,  pagesize, MPOL_PREFERRED, nodes->maskp,
 							nodes->size, 0) < 0)
 			err("mbind");