| From cfa825c86d3e879f081e4901fa62ff7ee581071d Mon Sep 17 00:00:00 2001 |
| From: Nathan Lynch <nathanl@linux.ibm.com> |
| Date: Thu, 18 Apr 2019 13:56:57 -0500 |
| Subject: powerpc/numa: improve control of topology updates |
| |
| [ Upstream commit 2d4d9b308f8f8dec68f6dbbff18c68ec7c6bd26f ] |
| |
| 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> |
| --- |
| arch/powerpc/mm/numa.c | 18 ++++++++++++------ |
| 1 file changed, 12 insertions(+), 6 deletions(-) |
| |
| diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c |
| index f976676004ad0..48c9a97eb2c33 100644 |
| --- a/arch/powerpc/mm/numa.c |
| +++ b/arch/powerpc/mm/numa.c |
| @@ -1498,6 +1498,9 @@ 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; |
| @@ -1531,6 +1534,9 @@ int stop_topology_update(void) |
| { |
| int rc = 0; |
| |
| + if (!topology_updates_enabled) |
| + return 0; |
| + |
| if (prrn_enabled) { |
| prrn_enabled = 0; |
| #ifdef CONFIG_SMP |
| @@ -1588,11 +1594,13 @@ 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; |
| @@ -1607,9 +1615,7 @@ 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(); |
| -- |
| 2.20.1 |
| |