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* [PATCH] acpi, numa: fix pxm to online numa node associations
@ 2018-03-16  3:08 ` Dan Williams
  0 siblings, 0 replies; 11+ messages in thread
From: Dan Williams @ 2018-03-16  3:08 UTC (permalink / raw)
  To: linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw
  Cc: linux-acpi-u79uwXL29TY76Z2rM5mHXA, Rafael J. Wysocki, Toshi Kani,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA,
	stable-u79uwXL29TY76Z2rM5mHXA

Commit 99759869faf1 "acpi: Add acpi_map_pxm_to_online_node()" added
support for mapping a given proximity to its nearest, by SLIT distance,
online node. However, it sometimes returns unexpected results due to the
fact that it switches from comparing the PXM node to the last node that
was closer than the current max.

    for_each_online_node(n) {
            dist = node_distance(node, n);
            if (dist < min_dist) {
                    min_dist = dist;
                    node = n;	<---- from this point we're using the
				      wrong node for node_distance()


Fixes: 99759869faf1 ("acpi: Add acpi_map_pxm_to_online_node()")
Cc: <stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Cc: Toshi Kani <toshi.kani-VXdhtT5mjnY@public.gmane.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>>
Signed-off-by: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
---
Rafael, I can take this through the nvdimm tree with your ack. I have a
few other nvdimm fixes pending for 4.16.

 drivers/acpi/numa.c |   10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index 8ccaae3550d2..85167603b9c9 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -103,25 +103,27 @@ int acpi_map_pxm_to_node(int pxm)
  */
 int acpi_map_pxm_to_online_node(int pxm)
 {
-	int node, n, dist, min_dist;
+	int node, min_node;
 
 	node = acpi_map_pxm_to_node(pxm);
 
 	if (node == NUMA_NO_NODE)
 		node = 0;
 
+	min_node = node;
 	if (!node_online(node)) {
-		min_dist = INT_MAX;
+		int min_dist = INT_MAX, dist, n;
+
 		for_each_online_node(n) {
 			dist = node_distance(node, n);
 			if (dist < min_dist) {
 				min_dist = dist;
-				node = n;
+				min_node = n;
 			}
 		}
 	}
 
-	return node;
+	return min_node;
 }
 EXPORT_SYMBOL(acpi_map_pxm_to_online_node);

^ permalink raw reply related	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2018-03-19 15:22 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-03-16  3:08 [PATCH] acpi, numa: fix pxm to online numa node associations Dan Williams
2018-03-16  3:08 ` Dan Williams
2018-03-16  3:08 ` Dan Williams
2018-03-17  1:16 ` Dan Williams
2018-03-17  1:16   ` Dan Williams
     [not found] ` <152116964416.8343.514895686858363582.stgit-p8uTFz9XbKj2zm6wflaqv1nYeNYlB/vhral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2018-03-18 21:55   ` Rafael J. Wysocki
2018-03-18 21:55     ` Rafael J. Wysocki
2018-03-18 21:55     ` Rafael J. Wysocki
2018-03-19 15:21   ` Kani, Toshi
2018-03-19 15:21     ` Kani, Toshi
2018-03-19 15:21     ` Kani, Toshi

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