[LTP] [PATCH 1/2] move_pages_support: use only allowed nodes

[LTP] [PATCH 1/2] move_pages_support: use only allowed nodes

[Jan Stancek]

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Some setups can lack memory on arbitrary nodes, use only nodes
returned by get_mempolicy(..., MPOL_F_MEMS_ALLOWED).

Signed-off-by: Jan Stancek <jstancek@redhat.com>
---
 .../syscalls/move_pages/move_pages_support.c       |   74 ++++++++++++++++----
 .../syscalls/move_pages/move_pages_support.h       |    1 +
 2 files changed, 62 insertions(+), 13 deletions(-)



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diff --git a/testcases/kernel/syscalls/move_pages/move_pages_support.c b/testcases/kernel/syscalls/move_pages/move_pages_support.c
index 320486f..83a841b 100644
--- a/testcases/kernel/syscalls/move_pages/move_pages_support.c
+++ b/testcases/kernel/syscalls/move_pages/move_pages_support.c
@@ -22,6 +22,7 @@
 #include <semaphore.h>
 #include "test.h"
 #include "usctest.h"
+#include "safe_macros.h"
 #include "move_pages_support.h"
 
 long get_page_size()
@@ -98,6 +99,46 @@ int alloc_pages_on_nodes(void **pages, unsigned int num, int *nodes)
 }
 
 /*
+ * get_allowed_nodes - get number and array of available nodes
+ * @num_allowed_nodes: pointer where number of available nodes will be stored
+ * @allowed_nodes: array of available node ids, this is MPOL_F_MEMS_ALLOWED
+ *                 node bitmask compacted (without holes), so that each field
+ *                 contains node number. If NULL only num_allowed_nodes is
+ *                 returned, otherwise it cotains new allocated array,
+ *                 which caller is responsible to free.
+ */
+void get_allowed_nodes(int *num_allowed_nodes, int **allowed_nodes)
+{
+#if HAVE_NUMA_H
+	int i;
+	struct bitmask *allowed_nodemask = NULL;
+
+	*num_allowed_nodes = 0;
+	allowed_nodemask = numa_allocate_nodemask();
+	if (allowed_nodes)
+		*allowed_nodes = SAFE_MALLOC(NULL,
+			sizeof(int)*allowed_nodemask->size);
+	/*
+	 * avoid numa_get_mems_allowed(), because of bug in getpol()
+	 * utility function in older versions:
+	 * http://www.spinics.net/lists/linux-numa/msg00849.html
+	 */
+	if (syscall(__NR_get_mempolicy, NULL, allowed_nodemask->maskp,
+		allowed_nodemask->size, 0, MPOL_F_MEMS_ALLOWED) < 0)
+		tst_resm(TFAIL|TERRNO, "get_mempolicy: MPOL_F_MEMS_ALLOWED");
+
+	for (i = 0; i <	allowed_nodemask->size; i++) {
+		if (numa_bitmask_isbitset(allowed_nodemask, i)) {
+			if (allowed_nodes)
+				(*allowed_nodes)[*num_allowed_nodes] = i;
+			(*num_allowed_nodes)++;
+		}
+	}
+	numa_bitmask_free(allowed_nodemask);
+#endif
+}
+
+/*
  * alloc_pages_linear() - allocate pages in each NUMA node
  * @pages: array in which the page pointers will be stored
  * @num: no. of pages to allocate
@@ -114,16 +155,18 @@ int alloc_pages_linear(void **pages, unsigned int num)
 
 #if HAVE_NUMA_H
 	unsigned int i;
-	unsigned int n;
+	unsigned int n = 0;
+	int num_allowed_nodes;
+	int *allowed_nodes;
 
-	n = 0;
+	get_allowed_nodes(&num_allowed_nodes, &allowed_nodes);
 	for (i = 0; i < num; i++) {
-		nodes[i] = n;
-
+		nodes[i] = allowed_nodes[n];
 		n++;
-		if (n > numa_max_node())
+		if (n >= num_allowed_nodes)
 			n = 0;
 	}
+	free(allowed_nodes);
 #endif
 
 	return alloc_pages_on_nodes(pages, num, nodes);
@@ -210,18 +253,19 @@ void verify_pages_linear(void **pages, int *status, unsigned int num)
 {
 #if HAVE_NUMA_H
 	unsigned int i;
-	unsigned int n;
+	unsigned int n = 0;
 	int nodes[num];
+	int num_allowed_nodes;
+	int *allowed_nodes;
 
-	n = 0;
-
+	get_allowed_nodes(&num_allowed_nodes, &allowed_nodes);
 	for (i = 0; i < num; i++) {
-		nodes[i] = i;
-
+		nodes[i] = allowed_nodes[n];
 		n++;
-		if (n > numa_max_node())
+		if (n >= num_allowed_nodes)
 			n = 0;
 	}
+	free(allowed_nodes);
 
 	verify_pages_on_nodes(pages, status, num, nodes);
 #endif
@@ -381,10 +425,14 @@ void free_sem(sem_t * sem, int num)
 void check_config(unsigned int min_nodes)
 {
 #if HAVE_NUMA_H && HAVE_NUMAIF_H
+	int num_allowed_nodes;
+	get_allowed_nodes(&num_allowed_nodes, NULL);
+
 	if (numa_available() < 0) {
 		tst_brkm(TCONF, NULL, "NUMA support is not available");
-	} else if (numa_max_node() < (min_nodes - 1)) {
-		tst_brkm(TCONF, NULL, "atleast 2 NUMA nodes are required");
+	} else if (num_allowed_nodes < min_nodes) {
+		tst_brkm(TCONF, NULL, "at least %d allowed NUMA nodes"
+		    " are required", min_nodes);
 	} else if (tst_kvercmp(2, 6, 18) < 0) {
 		tst_brkm(TCONF, NULL, "2.6.18 or greater kernel required");
 	}
diff --git a/testcases/kernel/syscalls/move_pages/move_pages_support.h b/testcases/kernel/syscalls/move_pages/move_pages_support.h
index fd78572..a10293b 100644
--- a/testcases/kernel/syscalls/move_pages/move_pages_support.h
+++ b/testcases/kernel/syscalls/move_pages/move_pages_support.h
@@ -29,6 +29,7 @@
 #include <semaphore.h>
 
 long get_page_size();
+void get_allowed_nodes(int *num_allowed_nodes, int **allowed_nodes);
 
 void free_pages(void **pages, unsigned int num);
 


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Re: [LTP] [PATCH 1/2] move_pages_support: use only allowed nodes

[Garrett Cooper]

On Fri, May 25, 2012 at 2:12 AM, Jan Stancek <jstancek@redhat.com> wrote:
>
> Some setups can lack memory on arbitrary nodes, use only nodes
> returned by get_mempolicy(..., MPOL_F_MEMS_ALLOWED).
>
> Signed-off-by: Jan Stancek <jstancek@redhat.com>
> ---
>  .../syscalls/move_pages/move_pages_support.c       |   74 ++++++++++++++++----
>  .../syscalls/move_pages/move_pages_support.h       |    1 +
>  2 files changed, 62 insertions(+), 13 deletions(-)

+	if (syscall(__NR_get_mempolicy, NULL, allowed_nodemask->maskp,
+		allowed_nodemask->size, 0, MPOL_F_MEMS_ALLOWED) < 0)
+		tst_resm(TFAIL|TERRNO, "get_mempolicy: MPOL_F_MEMS_ALLOWED");
+

Would tst_brkm be better here? Also, what happens in the negative case
(HAVE_NUMA_H is not defined)? Wouldn't that segfault accessing random
memory or something along those lines?

I think it would be better to design the API (get_allowed_nodes) to
return an integer value to denote success or failure, then test for
that in main and report errors there.

Thanks!
-Garrett

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