Hi, Oscar,
Thanks for doing this.
Oscar Salvador <osalvador@xxxxxxx> writes:
> At the time demote-on-reclaim was introduced, it was tied to
> CONFIG_HOTPLUG_CPU + CONFIG_MIGRATE, but that is not really
> accurate.
>
> The only two things we need to depen on is CONFIG_NUMA +
> CONFIG_MIGRATE, so clean this up.
> Furthermore, we only register the hotplug memory notifier
> when the system has CONFIG_MEMORY_HOTPLUG.
>
> Signed-off-by: Oscar Salvador <osalvador@xxxxxxx>
> Suggested-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
> ---
> include/linux/migrate.h | 5 ++++-
> mm/migrate.c | 11 ++++++-----
> mm/vmstat.c | 2 --
> 3 files changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index a4a336fd81fc..1efabe7bb5fc 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -49,14 +49,17 @@ int folio_migrate_mapping(struct address_space *mapping,
>
> extern bool numa_demotion_enabled;
> extern void migrate_on_reclaim_init(void);
> -#ifdef CONFIG_HOTPLUG_CPU
> +#ifdef CONFIG_NUMA
> extern void set_migration_target_nodes(void);
> +extern void migrate_on_reclaim_init(void);
> #else
> static inline void set_migration_target_nodes(void) {}
> +static inline void migrate_on_reclaim_init(void) {}
> #endif
> #else
>
> static inline void set_migration_target_nodes(void) {}
> +static inline void migrate_on_reclaim_init(void) {}
To avoid to duplicate the void definition. How about to usec
#if defined(CONFIG_MIGRATION) && defined(CONFIG_NUMA)
/* xxx */
#else
/* yyy */
#endif
And we need to put "numa_demotion_enabled" inside too. Because it is
defined inside CONFIG_NUMA too now.
> static inline void putback_movable_pages(struct list_head *l) {}
> static inline int migrate_pages(struct list_head *l, new_page_t new,
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 3364bfaddeef..118f71425241 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -2144,7 +2144,6 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
> return 0;
> }
> #endif /* CONFIG_NUMA_BALANCING */
> -#endif /* CONFIG_NUMA */
>
> /*
> * node_demotion[] example:
> @@ -2278,7 +2277,6 @@ int next_demotion_node(int node)
> return target;
> }
>
> -#if defined(CONFIG_HOTPLUG_CPU)
> /* Disable reclaim-based migration. */
> static void __disable_all_migrate_targets(void)
> {
> @@ -2471,6 +2469,7 @@ void set_migration_target_nodes(void)
> * __set_migration_target_nodes() can be used as opposed to
> * set_migration_target_nodes().
> */
> +#ifdef CONFIG_MEMORY_HOTPLUG
> static int __meminit migrate_on_reclaim_callback(struct notifier_block *self,
> unsigned long action, void *_arg)
> {
> @@ -2516,6 +2515,7 @@ static int __meminit migrate_on_reclaim_callback(struct notifier_block *self,
>
> return notifier_from_errno(0);
> }
> +#endif
>
> void __init migrate_on_reclaim_init(void)
> {
> @@ -2523,8 +2523,9 @@ void __init migrate_on_reclaim_init(void)
> sizeof(struct demotion_nodes),
> GFP_KERNEL);
> WARN_ON(!node_demotion);
> -
> +#ifdef CONFIG_MEMORY_HOTPLUG
> hotplug_memory_notifier(migrate_on_reclaim_callback, 100);
> +#endif
Another way is to add "#else" and void definition after
migrate_on_reclaim_callback(). But this isn't a big deal.
> /*
> * At this point, all numa nodes with memory/CPus have their state
> * properly set, so we can build the demotion order now.
> @@ -2535,7 +2536,6 @@ void __init migrate_on_reclaim_init(void)
> set_migration_target_nodes();
> cpus_read_unlock();
> }
> -#endif /* CONFIG_HOTPLUG_CPU */
>
> bool numa_demotion_enabled = false;
As above, this is under CONFIG_NUMA too now.
Best Regards,
Huang, Ying
> @@ -2596,4 +2596,5 @@ static int __init numa_init_sysfs(void)
> return err;
> }
> subsys_initcall(numa_init_sysfs);
> -#endif
> +#endif /* CONFIG_SYSFS */
> +#endif /* CONFIG_NUMA */
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index b75b1a64b54c..f2d0dec1062d 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -2111,9 +2111,7 @@ void __init init_mm_internals(void)
>
> start_shepherd_timer();
> #endif
> -#if defined(CONFIG_MIGRATION) && defined(CONFIG_HOTPLUG_CPU)
> migrate_on_reclaim_init();
> -#endif
> #ifdef CONFIG_PROC_FS
> proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op);
> proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op);
