On Wed 13-01-21 16:43:16, Dan Williams wrote:
> pfn_to_online_page() is already too large to be a macro or an inline
> function. In anticipation of further logic changes / growth, move it out
> of line.
>
> No functional change, just code movement.
>
> Reported-by: Michal Hocko <mhocko@xxxxxxxxxx>
I am not sure what r-b refers to. I suspect it is the overal problem
rather than this particular patch. Not that I care much but it might get
confusing because I do not remember ever complaining about
pfn_to_online_page to be too large.
> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
> Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
> Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
I do not remember any hot path which depends on pfn walk and a function
call would be clearly visible. If this ever turn out to be a problem we
can make it inline and push the heavy lifting out of line.
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Thanks!
> ---
> include/linux/memory_hotplug.h | 17 +----------------
> mm/memory_hotplug.c | 16 ++++++++++++++++
> 2 files changed, 17 insertions(+), 16 deletions(-)
>
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index 15acce5ab106..3d99de0db2dd 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -16,22 +16,7 @@ struct resource;
> struct vmem_altmap;
>
> #ifdef CONFIG_MEMORY_HOTPLUG
> -/*
> - * Return page for the valid pfn only if the page is online. All pfn
> - * walkers which rely on the fully initialized page->flags and others
> - * should use this rather than pfn_valid && pfn_to_page
> - */
> -#define pfn_to_online_page(pfn) \
> -({ \
> - struct page *___page = NULL; \
> - unsigned long ___pfn = pfn; \
> - unsigned long ___nr = pfn_to_section_nr(___pfn); \
> - \
> - if (___nr < NR_MEM_SECTIONS && online_section_nr(___nr) && \
> - pfn_valid_within(___pfn)) \
> - ___page = pfn_to_page(___pfn); \
> - ___page; \
> -})
> +struct page *pfn_to_online_page(unsigned long pfn);
>
> /*
> * Types for free bootmem stored in page->lru.next. These have to be in
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index f9d57b9be8c7..55a69d4396e7 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -300,6 +300,22 @@ static int check_hotplug_memory_addressable(unsigned long pfn,
> return 0;
> }
>
> +/*
> + * Return page for the valid pfn only if the page is online. All pfn
> + * walkers which rely on the fully initialized page->flags and others
> + * should use this rather than pfn_valid && pfn_to_page
> + */
> +struct page *pfn_to_online_page(unsigned long pfn)
> +{
> + unsigned long nr = pfn_to_section_nr(pfn);
> +
> + if (nr < NR_MEM_SECTIONS && online_section_nr(nr) &&
> + pfn_valid_within(pfn))
> + return pfn_to_page(pfn);
> + return NULL;
> +}
> +EXPORT_SYMBOL_GPL(pfn_to_online_page);
> +
> /*
> * Reasonably generic function for adding memory. It is
> * expected that archs that support memory hotplug will
--
Michal Hocko
SUSE Labs
