Re: [PATCH 02/21] mm/hugetlb: correct max_huge_pages accounting on demote

From: Florian Fainelli
Date: Wed Sep 14 2022 - 13:28:11 EST


On 9/14/22 10:23, Mike Kravetz wrote:
On 09/13/22 12:54, Doug Berger wrote:
When demoting a hugepage to a smaller order, the number of pages
added to the target hstate will be the size of the large page
divided by the size of the smaller page.

Fixes: 8531fc6f52f5 ("hugetlb: add hugetlb demote page support")
Signed-off-by: Doug Berger <opendmb@xxxxxxxxx>
---
mm/hugetlb.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e070b8593b37..79949893ac12 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3472,7 +3472,8 @@ static int demote_free_huge_page(struct hstate *h, struct page *page)
* based on pool changes for the demoted page.
*/
h->max_huge_pages--;
- target_hstate->max_huge_pages += pages_per_huge_page(h);
+ target_hstate->max_huge_pages += pages_per_huge_page(h) /
+ pages_per_huge_page(target_hstate);
return rc;
}

This has already been fixed here,

https://lore.kernel.org/linux-mm/20220823030209.57434-2-linmiaohe@xxxxxxxxxx/


Could we slap the Fixes tag when this Miaohe's patch series gets accepted since the offending commit is in v5.16 and beyond. Thanks!
--
Florian