From: Dave Hansen <[email protected]>
Once upon a time, the node demotion updates were driven solely by
memory hotplug events. But now, there are handlers for both CPU
and memory hotplug.
However, the #ifdef around the code checks only memory hotplug.
A system that has HOTPLUG_CPU=y but MEMORY_HOTPLUG=n would miss
CPU hotplug events.
Update the #ifdef around the common code. Add memory and
CPU-specific #ifdefs for their handlers. These memory/CPU
#ifdefs avoid unused function warnings when their Kconfig option
is off.
Fixes: 884a6e5d1f93 ("mm/migrate: update node demotion order on hotplug events")
Signed-off-by: Dave Hansen <[email protected]>
Cc: "Huang, Ying" <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Wei Xu <[email protected]>
Cc: Oscar Salvador <[email protected]>
Cc: David Rientjes <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Greg Thelen <[email protected]>
Cc: Yang Shi <[email protected]>
Cc: Andrew Morton <[email protected]>
---
b/mm/migrate.c | 46 +++++++++++++++++++++++++---------------------
1 file changed, 25 insertions(+), 21 deletions(-)
diff -puN mm/migrate.c~add-cpu-hotplug-config mm/migrate.c
--- a/mm/migrate.c~add-cpu-hotplug-config 2021-09-16 16:14:01.770140593 -0700
+++ b/mm/migrate.c 2021-09-17 11:30:19.197027668 -0700
@@ -3066,7 +3066,7 @@ void migrate_vma_finalize(struct migrate
EXPORT_SYMBOL(migrate_vma_finalize);
#endif /* CONFIG_DEVICE_PRIVATE */
-#if defined(CONFIG_MEMORY_HOTPLUG)
+#if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_HOTPLUG_CPU)
/* Disable reclaim-based migration. */
static void __disable_all_migrate_targets(void)
{
@@ -3248,25 +3248,7 @@ static void set_migration_target_nodes(v
put_online_mems();
}
-/*
- * React to hotplug events that might affect the migration targets
- * like events that online or offline NUMA nodes.
- *
- * The ordering is also currently dependent on which nodes have
- * CPUs. That means we need CPU on/offline notification too.
- */
-static int migration_online_cpu(unsigned int cpu)
-{
- set_migration_target_nodes();
- return 0;
-}
-
-static int migration_offline_cpu(unsigned int cpu)
-{
- set_migration_target_nodes();
- return 0;
-}
-
+#if defined(CONFIG_MEMORY_HOTPLUG)
/*
* This leaves migrate-on-reclaim transiently disabled between
* the MEM_GOING_OFFLINE and MEM_OFFLINE events. This runs
@@ -3313,6 +3295,27 @@ static int __meminit migrate_on_reclaim_
return notifier_from_errno(0);
}
+#endif /* CONFIG_MEMORY_HOTPLUG */
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * React to hotplug events that might affect the migration targets
+ * like events that online or offline NUMA nodes.
+ *
+ * The ordering is also currently dependent on which nodes have
+ * CPUs. That means we need CPU on/offline notification too.
+ */
+static int migration_online_cpu(unsigned int cpu)
+{
+ set_migration_target_nodes();
+ return 0;
+}
+
+static int migration_offline_cpu(unsigned int cpu)
+{
+ set_migration_target_nodes();
+ return 0;
+}
static int __init migrate_on_reclaim_init(void)
{
@@ -3333,4 +3336,5 @@ static int __init migrate_on_reclaim_ini
return 0;
}
late_initcall(migrate_on_reclaim_init);
-#endif /* CONFIG_MEMORY_HOTPLUG */
+#endif /* CONFIG_HOTPLUG_CPU */
+#endif /* CONFIG_MEMORY_HOTPLUG || CONFIG_HOTPLUG_CPU */
_
The initialization of node_demotion doesn't have to depend on
CONFIG_MEMORY_HOTPLUG and CONFIG_HOTPLUG_CPU. While you are at this,
can you replace cpuhp_setup_state() with cpuhp_setup_state_nocalls()
and also call set_migration_target_nodes() directly in
migrate_on_reclaim_init() outside
CONFIG_MEMORY_HOTPLUG/CONFIG_HOTPLUG_CPU? Thanks.
Wei
On Fri, Sep 17, 2021 at 3:35 PM Dave Hansen <[email protected]> wrote:
>
>
> From: Dave Hansen <[email protected]>
>
> Once upon a time, the node demotion updates were driven solely by
> memory hotplug events. But now, there are handlers for both CPU
> and memory hotplug.
>
> However, the #ifdef around the code checks only memory hotplug.
> A system that has HOTPLUG_CPU=y but MEMORY_HOTPLUG=n would miss
> CPU hotplug events.
>
> Update the #ifdef around the common code. Add memory and
> CPU-specific #ifdefs for their handlers. These memory/CPU
> #ifdefs avoid unused function warnings when their Kconfig option
> is off.
>
> Fixes: 884a6e5d1f93 ("mm/migrate: update node demotion order on hotplug events")
> Signed-off-by: Dave Hansen <[email protected]>
> Cc: "Huang, Ying" <[email protected]>
> Cc: Michal Hocko <[email protected]>
> Cc: Wei Xu <[email protected]>
> Cc: Oscar Salvador <[email protected]>
> Cc: David Rientjes <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: David Hildenbrand <[email protected]>
> Cc: Greg Thelen <[email protected]>
> Cc: Yang Shi <[email protected]>
> Cc: Andrew Morton <[email protected]>
> ---
>
> b/mm/migrate.c | 46 +++++++++++++++++++++++++---------------------
> 1 file changed, 25 insertions(+), 21 deletions(-)
>
> diff -puN mm/migrate.c~add-cpu-hotplug-config mm/migrate.c
> --- a/mm/migrate.c~add-cpu-hotplug-config 2021-09-16 16:14:01.770140593 -0700
> +++ b/mm/migrate.c 2021-09-17 11:30:19.197027668 -0700
> @@ -3066,7 +3066,7 @@ void migrate_vma_finalize(struct migrate
> EXPORT_SYMBOL(migrate_vma_finalize);
> #endif /* CONFIG_DEVICE_PRIVATE */
>
> -#if defined(CONFIG_MEMORY_HOTPLUG)
> +#if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_HOTPLUG_CPU)
> /* Disable reclaim-based migration. */
> static void __disable_all_migrate_targets(void)
> {
> @@ -3248,25 +3248,7 @@ static void set_migration_target_nodes(v
> put_online_mems();
> }
>
> -/*
> - * React to hotplug events that might affect the migration targets
> - * like events that online or offline NUMA nodes.
> - *
> - * The ordering is also currently dependent on which nodes have
> - * CPUs. That means we need CPU on/offline notification too.
> - */
> -static int migration_online_cpu(unsigned int cpu)
> -{
> - set_migration_target_nodes();
> - return 0;
> -}
> -
> -static int migration_offline_cpu(unsigned int cpu)
> -{
> - set_migration_target_nodes();
> - return 0;
> -}
> -
> +#if defined(CONFIG_MEMORY_HOTPLUG)
> /*
> * This leaves migrate-on-reclaim transiently disabled between
> * the MEM_GOING_OFFLINE and MEM_OFFLINE events. This runs
> @@ -3313,6 +3295,27 @@ static int __meminit migrate_on_reclaim_
>
> return notifier_from_errno(0);
> }
> +#endif /* CONFIG_MEMORY_HOTPLUG */
> +
> +#ifdef CONFIG_HOTPLUG_CPU
> +/*
> + * React to hotplug events that might affect the migration targets
> + * like events that online or offline NUMA nodes.
> + *
> + * The ordering is also currently dependent on which nodes have
> + * CPUs. That means we need CPU on/offline notification too.
> + */
> +static int migration_online_cpu(unsigned int cpu)
> +{
> + set_migration_target_nodes();
> + return 0;
> +}
> +
> +static int migration_offline_cpu(unsigned int cpu)
> +{
> + set_migration_target_nodes();
> + return 0;
> +}
>
> static int __init migrate_on_reclaim_init(void)
> {
> @@ -3333,4 +3336,5 @@ static int __init migrate_on_reclaim_ini
> return 0;
> }
> late_initcall(migrate_on_reclaim_init);
> -#endif /* CONFIG_MEMORY_HOTPLUG */
> +#endif /* CONFIG_HOTPLUG_CPU */
> +#endif /* CONFIG_MEMORY_HOTPLUG || CONFIG_HOTPLUG_CPU */
> _