Re: [PATCH v1] mm/memory_hotplug: Easier calculation to get pages to next section boundary

Baoquan He
2020-02-06T01:46:57Z

On 02/05/20 at 02:52pm, David Hildenbrand wrote:
> Let's use a calculation that's easier to understand and calculates the
> same result. Reusing existing macros makes this look nicer.
>
> We always want to have the number of pages (> 0) to the next section
> boundary, starting from the current pfn.
>
> Suggested-by: Segher Boessenkool <segher@kernel.crashing.org>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Baoquan He <bhe@redhat.com>
> Cc: Wei Yang <richardw.yang@linux.intel.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>

LGTM.

Reviewed-by: Baoquan He <bhe@redhat.com>

> ---
> mm/memory_hotplug.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 0a54ffac8c68..c30191183c04 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -528,7 +528,8 @@ void __remove_pages(unsigned long pfn, unsigned long nr_pages,
> for (; pfn < end_pfn; pfn += cur_nr_pages) {
> cond_resched();
> /* Select all remaining pages up to the next section boundary */
> - cur_nr_pages = min(end_pfn - pfn, -(pfn | PAGE_SECTION_MASK));
> + cur_nr_pages = min(end_pfn - pfn,
> + SECTION_ALIGN_UP(pfn + 1) - pfn);
> __remove_section(pfn, cur_nr_pages, map_offset, altmap);
> map_offset = 0;
> }
> --
> 2.24.1
>