mm/hugetlb: fix incorrect update of max_huge_pages

Patch series "A few fixup patches for hugetlb".

This series contains a few fixup patches to fix incorrect update of
max_huge_pages, fix WARN_ON(!kobj) in sysfs_create_group() and so on.
More details can be found in the respective changelogs.

This patch (of 6):

There should be pages_per_huge_page(h) /
pages_per_huge_page(target_hstate) pages incremented for
target_hstate->max_huge_pages when page is demoted.  Update max_huge_pages
accordingly for consistency.

Link: https://lkml.kernel.org/r/20220816130553.31406-1-linmiaohe@huawei.com
Link: https://lkml.kernel.org/r/20220816130553.31406-2-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ea1c7bf..e720529 100644 (file)
--- 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;
 }