-
Vlastimil Babka authored
In __free_one_page() we do the buddy merging arithmetics on "page/buddy index", which is just the lower MAX_ORDER bits of pfn. The operations we do that affect the higher bits are bitwise AND and subtraction (in that order), where the final result will be the same with the higher bits left unmasked, as long as these bits are equal for both buddies - which must be true by the definition of a buddy. We can therefore use pfn's directly instead of "index" and skip the zeroing of >MAX_ORDER bits. This can help a bit by itself, although compiler might be smart enough already. It also helps the next patch to avoid page_to_pfn() for memory hole checks. Link: http://lkml.kernel.org/r/20161216120009.20064-1-vbabka@suse.czSigned-off-by:
Vlastimil Babka <vbabka@suse.cz> Acked-by:
Mel Gorman <mgorman@techsingularity.net> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
76741e77