Re: [PATCH v3 14/19] mm/hugetlb: Free cross-zone bootmem gigantic pages after allocation
From: Muchun Song <muchun.song@linux.dev>
Date: 2026-06-15 08:45:35
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On Jun 14, 2026, at 17:55, Mike Rapoport [off-list ref] wrote: On Wed, Jun 03, 2026 at 10:53:04AM +0800, Muchun Song wrote:quoted
quoted
On Tue, 02 Jun 2026 18:10:34 +0800, Muchun Song [off-list ref] wrote:quoted
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 5e557c05d80a..218fb1ca45f4 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c@@ -3073,22 +3076,38 @@ static bool __init alloc_bootmem_huge_page(struct hstate *h, int nid)[ ... skip 26 lines ... ] + * pages belonging to the requested node. + */ + if (WARN_ON_ONCE(nid_request != NUMA_NO_NODE && nid != nid_request)) + list_add(&m->list, &huge_boot_pages[nid_request]); + else + list_add(&m->list, &huge_boot_pages[nid]);Can we just memblock_free() the page that intersects zones here?I had previously considered doing this, but then I realized that if we free the allocated cross-zone memory here, memblock is very likely to select the exact same block for the next allocation. This means we'd just end up with this cross-zone memory again, degrading allocation efficiency. Unless there is a way to mark the block so memblock avoids reallocating it, I ultimately chose to defer the release to prevent this issue from happening.You are right, there's no simple way to avoid memblock using the same range. The comment at hugetlb_hstate_alloc_pages() hints that we might want to split allocation of gigantic pages to be more explicit as a followup rework and then freeing of cross-zone pages would be cleaner as well.
Make sense. A followup rework is better. Thanks.
quoted
Thanks.-- Sincerely yours, Mike.