diff mbox series

[1/2] powerpc/numa: improve control of topology updates

Message ID 20190624170333.7837-2-manoj.iyer@canonical.com
State New
Headers show
Series [1/2] powerpc/numa: improve control of topology updates | expand

Commit Message

Manoj Iyer June 24, 2019, 5:03 p.m. UTC 
From: Nathan Lynch <nathanl@linux.ibm.com>

When booted with "topology_updates=no", or when "off" is written to
/proc/powerpc/topology_updates, NUMA reassignments are inhibited for
PRRN and VPHN events. However, migration and suspend unconditionally
re-enable reassignments via start_topology_update(). This is
incoherent.

Check the topology_updates_enabled flag in
start/stop_topology_update() so that callers of those APIs need not be
aware of whether reassignments are enabled. This allows the
administrative decision on reassignments to remain in force across
migrations and suspensions.

BugLink: https://bugs.launchpad.net/bugs/1833716

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
(cherry picked from commit 2d4d9b308f8f8dec68f6dbbff18c68ec7c6bd26f)
Signed-off-by: Manoj Iyer <manoj.iyer@canonical.com>
---
 arch/powerpc/mm/numa.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)
diff mbox series

Patch

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index c6ec7ea312e8..77424112184a 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -1604,6 +1604,9 @@  int start_topology_update(void)
 {
 	int rc = 0;
 
+	if (!topology_updates_enabled)
+		return 0;
+
 	if (firmware_has_feature(FW_FEATURE_PRRN)) {
 		if (!prrn_enabled) {
 			prrn_enabled = 1;
@@ -1633,6 +1636,9 @@  int stop_topology_update(void)
 {
 	int rc = 0;
 
+	if (!topology_updates_enabled)
+		return 0;
+
 	if (prrn_enabled) {
 		prrn_enabled = 0;
 #ifdef CONFIG_SMP
@@ -1679,11 +1685,13 @@  static ssize_t topology_write(struct file *file, const char __user *buf,
 
 	kbuf[read_len] = '\0';
 
-	if (!strncmp(kbuf, "on", 2))
+	if (!strncmp(kbuf, "on", 2)) {
+		topology_updates_enabled = true;
 		start_topology_update();
-	else if (!strncmp(kbuf, "off", 3))
+	} else if (!strncmp(kbuf, "off", 3)) {
 		stop_topology_update();
-	else
+		topology_updates_enabled = false;
+	} else
 		return -EINVAL;
 
 	return count;
@@ -1698,9 +1706,7 @@  static const struct file_operations topology_ops = {
 
 static int topology_update_init(void)
 {
-	/* Do not poll for changes if disabled at boot */
-	if (topology_updates_enabled)
-		start_topology_update();
+	start_topology_update();
 
 	if (vphn_enabled)
 		topology_schedule_update();