The patch titled
Subject: mm/hugetlb: don't wait for migration entry during follow page
has been added to the -mm mm-unstable branch. Its filename is
mm-hugetlb-dont-wait-for-migration-entry-during-follow-page.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb-dont-wait-for-migration-entry-during-follow-page.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: Peter Xu <peterx@xxxxxxxxxx>
Subject: mm/hugetlb: don't wait for migration entry during follow page
Date: Tue, 29 Nov 2022 14:35:18 -0500
That's what the code does with !hugetlb pages, so we should logically do
the same for hugetlb, so migration entry will also be treated as no page.
This is probably also the last piece in follow_page code that may sleep,
the last one should be removed in cf994dd8af27 ("mm/gup: remove
FOLL_MIGRATION", 2022-11-16).
Link: https://lkml.kernel.org/r/20221129193526.3588187-3-peterx@xxxxxxxxxx
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: James Houghton <jthoughton@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Nadav Amit <nadav.amit@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 11 -----------
1 file changed, 11 deletions(-)
--- a/mm/hugetlb.c~mm-hugetlb-dont-wait-for-migration-entry-during-follow-page
+++ a/mm/hugetlb.c
@@ -6234,7 +6234,6 @@ struct page *hugetlb_follow_page_mask(st
if (WARN_ON_ONCE(flags & FOLL_PIN))
return NULL;
-retry:
pte = huge_pte_offset(mm, haddr, huge_page_size(h));
if (!pte)
return NULL;
@@ -6257,16 +6256,6 @@ retry:
page = NULL;
goto out;
}
- } else {
- if (is_hugetlb_entry_migration(entry)) {
- spin_unlock(ptl);
- __migration_entry_wait_huge(pte, ptl);
- goto retry;
- }
- /*
- * hwpoisoned entry is treated as no_page_table in
- * follow_page_mask().
- */
}
out:
spin_unlock(ptl);
_
Patches currently in -mm which might be from peterx@xxxxxxxxxx are
mm-migrate-fix-read-only-page-got-writable-when-recover-pte.patch
mm-always-compile-in-pte-markers.patch
mm-use-pte-markers-for-swap-errors.patch
mm-uffd-sanity-check-write-bit-for-uffd-wp-protected-ptes.patch
selftests-vm-use-memfd-for-hugepage-mmap-test.patch
mm-thp-re-apply-mkdirty-for-small-pages-after-split.patch
mm-hugetlb-let-vma_offset_start-to-return-start.patch
mm-hugetlb-dont-wait-for-migration-entry-during-follow-page.patch
mm-hugetlb-document-huge_pte_offset-usage.patch
mm-hugetlb-move-swap-entry-handling-into-vma-lock-when-faulted.patch
mm-hugetlb-make-userfaultfd_huge_must_wait-safe-to-pmd-unshare.patch
mm-hugetlb-make-hugetlb_follow_page_mask-safe-to-pmd-unshare.patch
mm-hugetlb-make-follow_hugetlb_page-safe-to-pmd-unshare.patch
mm-hugetlb-make-walk_hugetlb_range-safe-to-pmd-unshare.patch
mm-hugetlb-make-page_vma_mapped_walk-safe-to-pmd-unshare.patch
mm-hugetlb-introduce-hugetlb_walk.patch
