The patch titled
Subject: mm/huge_memory: remove stale locking logic from __split_huge_pmd()
has been added to the -mm tree. Its filename is
mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd.patch
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: mm/huge_memory: remove stale locking logic from __split_huge_pmd()
Let's remove the stale logic that was required for reuse_swap_page().
Link: https://lkml.kernel.org/r/20220131162940.210846-10-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Don Dutile <ddutile@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Liang Zhang <zhangliang5@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Nadav Amit <nadav.amit@xxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Roman Gushchin <guro@xxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 32 +-------------------------------
1 file changed, 1 insertion(+), 31 deletions(-)
--- a/mm/huge_memory.c~mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd
+++ a/mm/huge_memory.c
@@ -2152,8 +2152,6 @@ void __split_huge_pmd(struct vm_area_str
{
spinlock_t *ptl;
struct mmu_notifier_range range;
- bool do_unlock_page = false;
- pmd_t _pmd;
mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
address & HPAGE_PMD_MASK,
@@ -2172,35 +2170,9 @@ void __split_huge_pmd(struct vm_area_str
goto out;
}
-repeat:
if (pmd_trans_huge(*pmd)) {
- if (!page) {
+ if (!page)
page = pmd_page(*pmd);
- /*
- * An anonymous page must be locked, to ensure that a
- * concurrent reuse_swap_page() sees stable mapcount;
- * but reuse_swap_page() is not used on shmem or file,
- * and page lock must not be taken when zap_pmd_range()
- * calls __split_huge_pmd() while i_mmap_lock is held.
- */
- if (PageAnon(page)) {
- if (unlikely(!trylock_page(page))) {
- get_page(page);
- _pmd = *pmd;
- spin_unlock(ptl);
- lock_page(page);
- spin_lock(ptl);
- if (unlikely(!pmd_same(*pmd, _pmd))) {
- unlock_page(page);
- put_page(page);
- page = NULL;
- goto repeat;
- }
- put_page(page);
- }
- do_unlock_page = true;
- }
- }
if (PageMlocked(page))
clear_page_mlock(page);
} else if (!(pmd_devmap(*pmd) || is_pmd_migration_entry(*pmd)))
@@ -2208,8 +2180,6 @@ repeat:
__split_huge_pmd_locked(vma, pmd, range.start, freeze);
out:
spin_unlock(ptl);
- if (do_unlock_page)
- unlock_page(page);
/*
* No need to double call mmu_notifier->invalidate_range() callback.
* They are 3 cases to consider inside __split_huge_pmd_locked():
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-optimize-do_wp_page-for-exclusive-pages-in-the-swapcache.patch
mm-optimize-do_wp_page-for-fresh-pages-in-local-lru-pagevecs.patch
mm-slightly-clarify-ksm-logic-in-do_swap_page.patch
mm-streamline-cow-logic-in-do_swap_page.patch
mm-huge_memory-streamline-cow-logic-in-do_huge_pmd_wp_page.patch
mm-khugepaged-remove-reuse_swap_page-usage.patch
mm-swapfile-remove-stale-reuse_swap_page.patch
mm-huge_memory-remove-stale-page_trans_huge_mapcount.patch
mm-huge_memory-remove-stale-locking-logic-from-__split_huge_pmd.patch
proc-vmcore-fix-possible-deadlock-on-concurrent-mmap-and-read.patch
