Messages in this thread | | | Subject | Re: [PATCH] mm/migrate: fix CPUHP state to update node demotion order | From | Mika Penttilä <> | Date | Sat, 18 Sep 2021 07:04:41 +0300 |
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Hi!
On 18.9.2021 5.58, Huang Ying wrote: > The node demotion order needs to be updated during CPU hotplug. > Because whether a NUMA node has CPU may influence the demotion order. > The update function should be called during CPU online/offline after > the node_states[N_CPU] has been updated. That is done in > CPUHP_AP_ONLINE_DYN during CPU online and in CPUHP_MM_VMSTAT_DEAD > during CPU offline. But in commit 884a6e5d1f93 ("mm/migrate: update > node demotion order on hotplug events"), the function to update node > demotion order is called in CPUHP_AP_ONLINE_DYN during CPU > online/offline. This doesn't satisfy the order requirement. So in > this patch, we added CPUHP_AP_MM_DEMOTION_ONLINE and > CPUHP_MM_DEMOTION_OFFLINE to be called after CPUHP_AP_ONLINE_DYN and > CPUHP_MM_VMSTAT_DEAD during CPU online/offline, and register the > update function on them. > > Fixes: 884a6e5d1f93 ("mm/migrate: update node demotion order on hotplug events") > Signed-off-by: "Huang, Ying" <ying.huang@intel.com> > Cc: Dave Hansen <dave.hansen@linux.intel.com> > Cc: Yang Shi <shy828301@gmail.com> > Cc: Zi Yan <ziy@nvidia.com> > Cc: Michal Hocko <mhocko@suse.com> > Cc: Wei Xu <weixugc@google.com> > Cc: Oscar Salvador <osalvador@suse.de> > Cc: David Rientjes <rientjes@google.com> > Cc: Dan Williams <dan.j.williams@intel.com> > Cc: David Hildenbrand <david@redhat.com> > Cc: Greg Thelen <gthelen@google.com> > Cc: Keith Busch <kbusch@kernel.org> > --- > include/linux/cpuhotplug.h | 2 ++ > mm/migrate.c | 8 +++++--- > 2 files changed, 7 insertions(+), 3 deletions(-) > > diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h > index 832d8a74fa59..5a92ea56f21b 100644 > --- a/include/linux/cpuhotplug.h > +++ b/include/linux/cpuhotplug.h > @@ -72,6 +72,7 @@ enum cpuhp_state { > CPUHP_SLUB_DEAD, > CPUHP_DEBUG_OBJ_DEAD, > CPUHP_MM_WRITEBACK_DEAD, > + CPUHP_MM_DEMOTION_OFFLINE, > CPUHP_MM_VMSTAT_DEAD, > CPUHP_SOFTIRQ_DEAD, > CPUHP_NET_MVNETA_DEAD, > @@ -240,6 +241,7 @@ enum cpuhp_state { > CPUHP_AP_BASE_CACHEINFO_ONLINE, > CPUHP_AP_ONLINE_DYN, > CPUHP_AP_ONLINE_DYN_END = CPUHP_AP_ONLINE_DYN + 30, > + CPUHP_AP_MM_DEMOTION_ONLINE, > CPUHP_AP_X86_HPET_ONLINE, > CPUHP_AP_X86_KVM_CLK_ONLINE, > CPUHP_AP_DTPM_CPU_ONLINE, > diff --git a/mm/migrate.c b/mm/migrate.c > index a6a7743ee98f..77d107a4577f 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -3278,9 +3278,8 @@ static int __init migrate_on_reclaim_init(void) > { > int ret; > > - ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "migrate on reclaim", > - migration_online_cpu, > - migration_offline_cpu); > + ret = cpuhp_setup_state_nocalls(CPUHP_MM_DEMOTION_OFFLINE, "mm/demotion:offline", > + NULL, migration_offline_cpu); > /* > * In the unlikely case that this fails, the automatic > * migration targets may become suboptimal for nodes > @@ -3288,6 +3287,9 @@ static int __init migrate_on_reclaim_init(void) > * rare case, do not bother trying to do anything special. > */ > WARN_ON(ret < 0); > + ret = cpuhp_setup_state_nocalls(CPUHP_AP_MM_DEMOTION_ONLINE, "mm/demotion:online", > + migration_online_cpu, NULL); >
You changed to _nocalls variant, how does this handle initialization for cpus present at boot?
Thanks, Mika
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