Re: [PATCH v12 14/31] mm/migrate: Pass vm_fault pointer to migrate_misplaced_page()

[Jerome Glisse <jglisse@redhat.com>]

On Tue, Apr 16, 2019 at 03:45:05PM +0200, Laurent Dufour wrote:
> migrate_misplaced_page() is only called during the page fault handling so
> it's better to pass the pointer to the struct vm_fault instead of the vma.
> 
> This way during the speculative page fault path the saved vma->vm_flags
> could be used.
> 
> Acked-by: David Rientjes <rientjes@google.com>
> Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>

Reviewed-by: Jérôme Glisse <jglisse@redhat.com>

> ---
>  include/linux/migrate.h | 4 ++--
>  mm/memory.c             | 2 +-
>  mm/migrate.c            | 4 ++--
>  3 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/include/linux/migrate.h b/include/linux/migrate.h
> index e13d9bf2f9a5..0197e40325f8 100644
> --- a/include/linux/migrate.h
> +++ b/include/linux/migrate.h
> @@ -125,14 +125,14 @@ static inline void __ClearPageMovable(struct page *page)
>  #ifdef CONFIG_NUMA_BALANCING
>  extern bool pmd_trans_migrating(pmd_t pmd);
>  extern int migrate_misplaced_page(struct page *page,
> -				  struct vm_area_struct *vma, int node);
> +				  struct vm_fault *vmf, int node);
>  #else
>  static inline bool pmd_trans_migrating(pmd_t pmd)
>  {
>  	return false;
>  }
>  static inline int migrate_misplaced_page(struct page *page,
> -					 struct vm_area_struct *vma, int node)
> +					 struct vm_fault *vmf, int node)
>  {
>  	return -EAGAIN; /* can't migrate now */
>  }
> diff --git a/mm/memory.c b/mm/memory.c
> index d0de58464479..56802850e72c 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -3747,7 +3747,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
>  	}
>  
>  	/* Migrate to the requested node */
> -	migrated = migrate_misplaced_page(page, vma, target_nid);
> +	migrated = migrate_misplaced_page(page, vmf, target_nid);
>  	if (migrated) {
>  		page_nid = target_nid;
>  		flags |= TNF_MIGRATED;
> diff --git a/mm/migrate.c b/mm/migrate.c
> index a9138093a8e2..633bd9abac54 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1938,7 +1938,7 @@ bool pmd_trans_migrating(pmd_t pmd)
>   * node. Caller is expected to have an elevated reference count on
>   * the page that will be dropped by this function before returning.
>   */
> -int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
> +int migrate_misplaced_page(struct page *page, struct vm_fault *vmf,
>  			   int node)
>  {
>  	pg_data_t *pgdat = NODE_DATA(node);
> @@ -1951,7 +1951,7 @@ int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
>  	 * with execute permissions as they are probably shared libraries.
>  	 */
>  	if (page_mapcount(page) != 1 && page_is_file_cache(page) &&
> -	    (vma->vm_flags & VM_EXEC))
> +	    (vmf->vma_flags & VM_EXEC))
>  		goto out;
>  
>  	/*
> -- 
> 2.21.0
>