Hi Andi,
> Date: Sat, 10 Jan 2009 07:18:09 +0100
> From: Andi Kleen <andi@xxxxxxxxxxxxxx>
> To: Andi Kleen <andi@xxxxxxxxxxxxxx>
> Cc: cpw@xxxxxxx, linux-numa@xxxxxxxxxxxxxxx
> Subject: [PATCH] Fix test/prefered v2
>
> 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.
There is numa_num_possible_nodes(). It determines the size of
the kernel nodemask_t (MAX_NUMNODES) by counting the size of Mems_allowed:
in /proc/self/status. (And if that is not available, falls back to a
procedure very similar to your max_numnode().)
The patch, but using numa_num_possible_nodes() is below.
It returns the same results, in my tests.
Is there some subtle difference between numa_num_possible_nodes() and
your function that I'm missing?
-Cliff
> - The loop set the node in the wrong mask, breaking the test
>
> v2: Correct max_numnode detection
>
> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
>
> --- 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");
---
test/prefered.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
Index: numactl-dev/test/prefered.c
===================================================================
--- numactl-dev.orig/test/prefered.c
+++ numactl-dev/test/prefered.c
@@ -6,20 +6,22 @@
#include <assert.h>
#include <unistd.h>
#include <stdlib.h>
+#include <errno.h>
#define err(x) perror(x),exit(1)
int main(void)
{
int max = numa_max_node();
+ int maxmask = numa_num_possible_nodes();
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,
@@ -33,7 +35,7 @@ int main(void)
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)
--
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