diff options
| author | Wei Yang <richard.weiyang@gmail.com> | 2025-08-28 09:16:18 +0000 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-09-13 16:55:25 -0700 |
| commit | 204dfefe039263d7b81857c7f320834b5c7dc94e (patch) | |
| tree | 67b430839e7e5bfe44948ce625693bff02aa2646 | |
| parent | c66ae64401d148733ff564488160b58a659b80a5 (diff) | |
mm/page_alloc: find_large_buddy() from start_pfn aligned order
We iterate pfn from order 0 to MAX_PAGE_ORDER aligned to find large buddy.
While if the order is less than start_pfn aligned order, we would get the
same pfn and do the same check again.
Iterate from start_pfn aligned order to reduce duplicated work.
[richard.weiyang@gmail.com: add comment on assignment of order]
Link: https://lkml.kernel.org/r/20250828091618.7869-1-richard.weiyang@gmail.com
Link: https://lkml.kernel.org/r/20250902025807.11467-1-richard.weiyang@gmail.com
Link: https://lkml.kernel.org/r/20250828091618.7869-1-richard.weiyang@gmail.com
Link: https://lkml.kernel.org/r/20250902025807.11467-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
| -rw-r--r-- | mm/page_alloc.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2df6ee6998ab..0873d640f26c 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2033,7 +2033,13 @@ static int move_freepages_block(struct zone *zone, struct page *page, /* Look for a buddy that straddles start_pfn */ static unsigned long find_large_buddy(unsigned long start_pfn) { - int order = 0; + /* + * If start_pfn is not an order-0 PageBuddy, next PageBuddy containing + * start_pfn has minimal order of __ffs(start_pfn) + 1. Start checking + * the order with __ffs(start_pfn). If start_pfn is order-0 PageBuddy, + * the starting order does not matter. + */ + int order = start_pfn ? __ffs(start_pfn) : MAX_PAGE_ORDER; struct page *page; unsigned long pfn = start_pfn; |