Re: [PATCH v3 07/16] mm: move some stuff to mm/page_alloc.h

["Vlastimil Babka (SUSE)" <vbabka@kernel.org>]

On 6/29/26 15:11, Brendan Jackman wrote:
> Some of this stuff in the public header is only used internally so
> shrink the scope to avoid silently growing new users.
> 
> drain_local_pages() is still used from kernel/power/snapshot.c so that
> needs to stay behind.
> 
> Signed-off-by: Brendan Jackman <jackmanb@google.com>

Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>

> ---
>  include/linux/gfp.h | 26 --------------------------
>  mm/page_alloc.h     | 28 ++++++++++++++++++++++++++++
>  mm/vmstat.c         |  1 +
>  3 files changed, 29 insertions(+), 26 deletions(-)
> 
> diff --git a/include/linux/gfp.h b/include/linux/gfp.h
> index cdf95a9f0b87c..01d6d2591f49e 100644
> --- a/include/linux/gfp.h
> +++ b/include/linux/gfp.h
> @@ -17,28 +17,6 @@ struct mempolicy;
>  #define __default_gfp(a,b,...) b
>  #define default_gfp(...) __default_gfp(,##__VA_ARGS__,GFP_KERNEL)
>  
> -/* Convert GFP flags to their corresponding migrate type */
> -#define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)
> -#define GFP_MOVABLE_SHIFT 3
> -
> -static inline int gfp_migratetype(const gfp_t gfp_flags)
> -{
> -	VM_WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
> -	BUILD_BUG_ON((1UL << GFP_MOVABLE_SHIFT) != ___GFP_MOVABLE);
> -	BUILD_BUG_ON((___GFP_MOVABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_MOVABLE);
> -	BUILD_BUG_ON((___GFP_RECLAIMABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_RECLAIMABLE);
> -	BUILD_BUG_ON(((___GFP_MOVABLE | ___GFP_RECLAIMABLE) >>
> -		      GFP_MOVABLE_SHIFT) != MIGRATE_HIGHATOMIC);
> -
> -	if (unlikely(page_group_by_mobility_disabled))
> -		return MIGRATE_UNMOVABLE;
> -
> -	/* Group based on mobility */
> -	return (__force unsigned long)(gfp_flags & GFP_MOVABLE_MASK) >> GFP_MOVABLE_SHIFT;
> -}
> -#undef GFP_MOVABLE_MASK
> -#undef GFP_MOVABLE_SHIFT
> -
>  static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags)
>  {
>  	return !!(gfp_flags & __GFP_DIRECT_RECLAIM);
> @@ -395,10 +373,6 @@ extern void free_pages(unsigned long addr, unsigned int order);
>  #define __free_page(page) __free_pages((page), 0)
>  #define free_page(addr) free_pages((addr), 0)
>  
> -void page_alloc_init_cpuhp(void);
> -bool decay_pcp_high(struct zone *zone, struct per_cpu_pages *pcp);
> -void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp);
> -void drain_all_pages(struct zone *zone);
>  void drain_local_pages(struct zone *zone);
>  
>  void page_alloc_init_late(void);
> diff --git a/mm/page_alloc.h b/mm/page_alloc.h
> index e16f905f859a7..af83764788b96 100644
> --- a/mm/page_alloc.h
> +++ b/mm/page_alloc.h
> @@ -266,6 +266,34 @@ static inline bool free_area_empty(struct free_area *area, int migratetype)
>  	return list_empty(&area->free_list[migratetype]);
>  }
>  
> +/* Convert GFP flags to their corresponding migrate type */
> +#define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)
> +#define GFP_MOVABLE_SHIFT 3
> +
> +static inline int gfp_migratetype(const gfp_t gfp_flags)
> +{
> +	VM_WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
> +	BUILD_BUG_ON((1UL << GFP_MOVABLE_SHIFT) != ___GFP_MOVABLE);
> +	BUILD_BUG_ON((___GFP_MOVABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_MOVABLE);
> +	BUILD_BUG_ON((___GFP_RECLAIMABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_RECLAIMABLE);
> +	BUILD_BUG_ON(((___GFP_MOVABLE | ___GFP_RECLAIMABLE) >>
> +		      GFP_MOVABLE_SHIFT) != MIGRATE_HIGHATOMIC);
> +
> +	if (unlikely(page_group_by_mobility_disabled))
> +		return MIGRATE_UNMOVABLE;
> +
> +	/* Group based on mobility */
> +	return (__force unsigned long)(gfp_flags & GFP_MOVABLE_MASK) >> GFP_MOVABLE_SHIFT;
> +}
> +#undef GFP_MOVABLE_MASK
> +#undef GFP_MOVABLE_SHIFT
> +
> +bool decay_pcp_high(struct zone *zone, struct per_cpu_pages *pcp);
> +void drain_zone_pages(struct zone *zone, struct per_cpu_pages *pcp);
> +void drain_all_pages(struct zone *zone);
> +void drain_local_pages(struct zone *zone);
> +
> +void page_alloc_init_cpuhp(void);
>  void page_alloc_sysctl_init(void);
>  
>  #endif /* __MM_PAGE_ALLOC_H */
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index 7b93fbf9af092..3b5cb1031f720 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -30,6 +30,7 @@
>  #include <linux/sched/isolation.h>
>  
>  #include "internal.h"
> +#include "page_alloc.h"
>  
>  #ifdef CONFIG_PROC_FS
>  #ifdef CONFIG_NUMA
>