The patch titled
Subject: hugetlb: check for hugetlb folio before vmemmap_restore
has been added to the -mm mm-unstable branch. Its filename is
hugetlb-check-for-hugetlb-folio-before-vmemmap_restore.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/hugetlb-check-for-hugetlb-folio-before-vmemmap_restore.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: hugetlb: check for hugetlb folio before vmemmap_restore
Date: Mon, 16 Oct 2023 19:55:49 -0700
In commit d8f5f7e445f0 ("hugetlb: set hugetlb page flag before
optimizing vmemmap") checks were added to print a warning if
hugetlb_vmemmap_restore was called on a non-hugetlb page.
This was mostly due to ordering issues in the hugetlb page set up and tear
down sequencees. One place missed was the routine
dissolve_free_huge_page.
Naoya Horiguchi noted: "I saw that VM_WARN_ON_ONCE() in
hugetlb_vmemmap_restore is triggered when memory_failure() is called on a
free hugetlb page with vmemmap optimization disabled (the warning is not
triggered if vmemmap optimization is enabled). I think that we need check
folio_test_hugetlb() before dissolve_free_huge_page() calls
hugetlb_vmemmap_restore_folio()."
Perform the check as suggested by Naoya.
Link: https://lkml.kernel.org/r/20231017032140.GA3680@monkey
Fixes: d8f5f7e445f0 ("hugetlb: set hugetlb page flag before optimizing vmemmap")
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Suggested-by: Naoya Horiguchi <naoya.horiguchi@xxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Barry Song <song.bao.hua@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joao Martins <joao.m.martins@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Xiongchun Duan <duanxiongchun@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 24 +++++++++++++++---------
1 file changed, 15 insertions(+), 9 deletions(-)
--- a/mm/hugetlb.c~hugetlb-check-for-hugetlb-folio-before-vmemmap_restore
+++ a/mm/hugetlb.c
@@ -2322,17 +2322,23 @@ retry:
* need to adjust max_huge_pages if the page is not freed.
* Attempt to allocate vmemmmap here so that we can take
* appropriate action on failure.
+ *
+ * The folio_test_hugetlb check here is because
+ * remove_hugetlb_folio will clear hugetlb folio flag for
+ * non-vmemmap optimized hugetlb folios.
*/
- rc = hugetlb_vmemmap_restore(h, &folio->page);
- if (!rc) {
- update_and_free_hugetlb_folio(h, folio, false);
- } else {
- spin_lock_irq(&hugetlb_lock);
- add_hugetlb_folio(h, folio, false);
- h->max_huge_pages++;
- spin_unlock_irq(&hugetlb_lock);
- }
+ if (folio_test_hugetlb(folio)) {
+ rc = hugetlb_vmemmap_restore(h, &folio->page);
+ if (rc) {
+ spin_lock_irq(&hugetlb_lock);
+ add_hugetlb_folio(h, folio, false);
+ h->max_huge_pages++;
+ goto out;
+ }
+ } else
+ rc = 0;
+ update_and_free_hugetlb_folio(h, folio, false);
return rc;
}
out:
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
hugetlb-check-for-hugetlb-folio-before-vmemmap_restore.patch
hugetlb-optimize-update_and_free_pages_bulk-to-avoid-lock-cycles.patch
hugetlb-restructure-pool-allocations.patch
hugetlb-perform-vmemmap-optimization-on-a-list-of-pages.patch
hugetlb-perform-vmemmap-restoration-on-a-list-of-pages.patch
hugetlb-batch-freeing-of-vmemmap-pages.patch
hugetlb-batch-tlb-flushes-when-restoring-vmemmap.patch
