The patch titled
Subject: hugetlb-simplify-hugetlb-handling-in-follow_page_mask-v4
has been added to the -mm mm-unstable branch. Its filename is
hugetlb-simplify-hugetlb-handling-in-follow_page_mask-v4.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/hugetlb-simplify-hugetlb-handling-in-follow_page_mask-v4.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-simplify-hugetlb-handling-in-follow_page_mask-v4
Date: Fri, 28 Oct 2022 11:11:08 -0700
remove vma (pmd sharing) locking as this can be called with FOLL_NOWAIT,
per Peter
Link: https://lkml.kernel.org/r/20221028181108.119432-1-mike.kravetz@xxxxxxxxxx
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Suggested-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
Cc: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/hugetlb.c~hugetlb-simplify-hugetlb-handling-in-follow_page_mask-v4
+++ a/mm/hugetlb.c
@@ -6265,17 +6265,9 @@ struct page *hugetlb_follow_page_mask(st
return NULL;
retry:
- /*
- * vma lock prevents racing with another thread doing a pmd unshare.
- * This keeps pte as returned by huge_pte_offset valid.
- */
- hugetlb_vma_lock_read(vma);
-
pte = huge_pte_offset(mm, haddr, huge_page_size(h));
- if (!pte) {
- hugetlb_vma_unlock_read(vma);
+ if (!pte)
return NULL;
- }
ptl = huge_pte_lock(h, mm, pte);
entry = huge_ptep_get(pte);
@@ -6309,7 +6301,6 @@ retry:
}
out:
spin_unlock(ptl);
- hugetlb_vma_unlock_read(vma);
return page;
}
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
hugetlb-dont-delete-vma_lock-in-hugetlb-madv_dontneed-processing.patch
hugetlb-simplify-hugetlb-handling-in-follow_page_mask.patch
hugetlb-simplify-hugetlb-handling-in-follow_page_mask-v4.patch
