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powerpc/numa: improve control of topology updates 

[ Upstream commit 2d4d9b308f ]

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.

Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Nathan Lynch 2019-04-18 13:56:57 -05:00 committed by Greg Kroah-Hartman
parent 9449e18774
commit 667890535f
1 changed files with 12 additions and 6 deletions
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18
arch/powerpc/mm/numa.c
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@ -1561,6 +1561,9 @@ 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;
@ -1590,6 +1593,9 @@ int stop_topology_update(void)
{
int rc = 0;
if (!topology_updates_enabled)
return 0;
if (prrn_enabled) {
prrn_enabled = 0;
#ifdef CONFIG_SMP
@ -1635,11 +1641,13 @@ 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;
@ -1654,9 +1662,7 @@ 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 (!proc_create("powerpc/topology_updates", 0644, NULL, &topology_ops))
return -ENOMEM;