Re: [PATCH] mm/page_alloc: Clarify some migratetype fallback code

Brendan Jackman
2025-02-21T17:25:29Z

On Tue, 18 Feb 2025 at 21:38, Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> @@ -1930,7 +1929,7 @@ steal_suitable_fallback(struct zone *zone, struct page *page,
/*
* This can happen due to races and we want to prevent broken
* highatomic accounting.
*/
> if (is_migrate_highatomic(block_type))
> - goto single_page;
> + return NULL;

Side question: when does this happen? Might have a spooky gap in my
understanding here as I thought the only reason the pageblock typed
was changed without the zone lock held was during memory hotplug.