The quilt patch titled
Subject: mm/mglru: allow pte_offset_map_nolock() to fail
has been removed from the -mm tree. Its filename was
mm-mglru-allow-pte_offset_map_nolock-to-fail.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: mm/mglru: allow pte_offset_map_nolock() to fail
Date: Thu, 8 Jun 2023 18:37:12 -0700 (PDT)
MGLRU's walk_pte_range() use the safer pte_offset_map_nolock(), rather
than pte_lockptr(), to get the ptl for its trylock. Just return false and
move on to next extent if it fails, like when the trylock fails. Remove
the VM_WARN_ON_ONCE(pmd_leaf) since that will happen, rarely.
Link: https://lkml.kernel.org/r/51ece73e-7398-2e4a-2384-56708c87844f@xxxxxxxxxx
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Acked-by: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Song Liu <song@xxxxxxxxxx>
Cc: Steven Price <steven.price@xxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Zack Rusin <zackr@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/vmscan.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
--- a/mm/vmscan.c~mm-mglru-allow-pte_offset_map_nolock-to-fail
+++ a/mm/vmscan.c
@@ -4024,15 +4024,15 @@ static bool walk_pte_range(pmd_t *pmd, u
struct pglist_data *pgdat = lruvec_pgdat(walk->lruvec);
int old_gen, new_gen = lru_gen_from_seq(walk->max_seq);
- VM_WARN_ON_ONCE(pmd_leaf(*pmd));
-
- ptl = pte_lockptr(args->mm, pmd);
- if (!spin_trylock(ptl))
+ pte = pte_offset_map_nolock(args->mm, pmd, start & PMD_MASK, &ptl);
+ if (!pte)
+ return false;
+ if (!spin_trylock(ptl)) {
+ pte_unmap(pte);
return false;
+ }
arch_enter_lazy_mmu_mode();
-
- pte = pte_offset_map(pmd, start & PMD_MASK);
restart:
for (i = pte_index(start), addr = start; addr != end; i++, addr += PAGE_SIZE) {
unsigned long pfn;
@@ -4073,10 +4073,8 @@ restart:
if (i < PTRS_PER_PTE && get_next_vma(PMD_MASK, PAGE_SIZE, args, &start, &end))
goto restart;
- pte_unmap(pte);
-
arch_leave_lazy_mmu_mode();
- spin_unlock(ptl);
+ pte_unmap_unlock(pte, ptl);
return suitable_to_scan(total, young);
}
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
