The PPC mobility code may receive RTAS requests to perform PRRN topology changes at any time, including during LPAR migration operations. In some configurations where the affinity of CPUs or memory is being changed on that platform, the PRRN requests may apply or refer to outdated information prior to the complete update of the device-tree. This patch changes the duration for which topology updates are suppressed during LPAR migrations from just the rtas_ibm_suspend_me / 'ibm,suspend-me' call(s) to cover the entire 'migration_store' operation to allow all changes to the device-tree to be applied prior to accepting and applying any PRRN requests.
For tracking purposes, pr_info notices are added to the functions start_topology_update() and stop_topology_update() of 'numa.c'. Signed-off-by: Michael Bringmann <m...@linux.vnet.ibm.com> --- arch/powerpc/kernel/rtas.c | 4 ---- arch/powerpc/mm/numa.c | 6 ++++++ arch/powerpc/platforms/pseries/mobility.c | 5 +++++ 3 files changed, 11 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index 8afd146..28d8b57 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -981,8 +981,6 @@ int rtas_ibm_suspend_me(u64 handle) goto out; } - stop_topology_update(); - /* Call function on all CPUs. One of us will make the * rtas call */ @@ -994,8 +992,6 @@ int rtas_ibm_suspend_me(u64 handle) if (atomic_read(&data.error) != 0) printk(KERN_ERR "Error doing global join\n"); - start_topology_update(); - /* Take down CPUs not online prior to suspend */ cpuret = rtas_offline_cpus_mask(offline_mask); if (cpuret) diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c index b5a71ba..0ade0a1 100644 --- a/arch/powerpc/mm/numa.c +++ b/arch/powerpc/mm/numa.c @@ -1518,6 +1518,10 @@ int start_topology_update(void) } } + pr_info("Starting topology update%s%s\n", + (prrn_enabled ? " prrn_enabled" : ""), + (vphn_enabled ? " vphn_enabled" : "")); + return rc; } @@ -1539,6 +1543,8 @@ int stop_topology_update(void) rc = del_timer_sync(&topology_timer); } + pr_info("Stopping topology update\n"); + return rc; } diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c index 23fb9ac..49ebefd 100644 --- a/arch/powerpc/platforms/pseries/mobility.c +++ b/arch/powerpc/platforms/pseries/mobility.c @@ -373,6 +373,8 @@ static ssize_t migration_store(struct class *class, if (rc) return rc; + stop_topology_update(); + do { rc = rtas_ibm_suspend_me(streamid); if (rc == -EAGAIN) @@ -383,6 +385,9 @@ static ssize_t migration_store(struct class *class, return rc; post_mobility_fixup(); + + start_topology_update(); + return count; }