The patch titled
Subject: mm/migrate: remove cruft from migration_entry_wait()s
has been added to the -mm mm-unstable branch. Its filename is
mm-migrate-remove-cruft-from-migration_entry_waits.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-migrate-remove-cruft-from-migration_entry_waits.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: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: mm/migrate: remove cruft from migration_entry_wait()s
Date: Thu, 8 Jun 2023 18:08:20 -0700 (PDT)
migration_entry_wait_on_locked() does not need to take a mapped pte
pointer, its callers can do the unmap first. Annotate it with
__releases(ptl) to reduce sparse warnings.
Fold __migration_entry_wait_huge() into migration_entry_wait_huge(). Fold
__migration_entry_wait() into migration_entry_wait(), preferring the
tighter pte_offset_map_lock() to pte_offset_map() and pte_lockptr().
Link: https://lkml.kernel.org/r/b0e2a532-cdf2-561b-e999-f3b13b8d6d3@xxxxxxxxxx
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Reviewed-by: 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: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Zack Rusin <zackr@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/migrate.h | 4 ++--
include/linux/swapops.h | 17 +++--------------
mm/filemap.c | 13 ++++---------
mm/migrate.c | 37 +++++++++++++------------------------
4 files changed, 22 insertions(+), 49 deletions(-)
--- a/include/linux/migrate.h~mm-migrate-remove-cruft-from-migration_entry_waits
+++ a/include/linux/migrate.h
@@ -75,8 +75,8 @@ bool isolate_movable_page(struct page *p
int migrate_huge_page_move_mapping(struct address_space *mapping,
struct folio *dst, struct folio *src);
-void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
- spinlock_t *ptl);
+void migration_entry_wait_on_locked(swp_entry_t entry, spinlock_t *ptl)
+ __releases(ptl);
void folio_migrate_flags(struct folio *newfolio, struct folio *folio);
void folio_migrate_copy(struct folio *newfolio, struct folio *folio);
int folio_migrate_mapping(struct address_space *mapping,
--- a/include/linux/swapops.h~mm-migrate-remove-cruft-from-migration_entry_waits
+++ a/include/linux/swapops.h
@@ -332,15 +332,9 @@ static inline bool is_migration_entry_di
return false;
}
-extern void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
- spinlock_t *ptl);
extern void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
unsigned long address);
-#ifdef CONFIG_HUGETLB_PAGE
-extern void __migration_entry_wait_huge(struct vm_area_struct *vma,
- pte_t *ptep, spinlock_t *ptl);
extern void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte);
-#endif /* CONFIG_HUGETLB_PAGE */
#else /* CONFIG_MIGRATION */
static inline swp_entry_t make_readable_migration_entry(pgoff_t offset)
{
@@ -362,15 +356,10 @@ static inline int is_migration_entry(swp
return 0;
}
-static inline void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
- spinlock_t *ptl) { }
static inline void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
- unsigned long address) { }
-#ifdef CONFIG_HUGETLB_PAGE
-static inline void __migration_entry_wait_huge(struct vm_area_struct *vma,
- pte_t *ptep, spinlock_t *ptl) { }
-static inline void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) { }
-#endif /* CONFIG_HUGETLB_PAGE */
+ unsigned long address) { }
+static inline void migration_entry_wait_huge(struct vm_area_struct *vma,
+ pte_t *pte) { }
static inline int is_writable_migration_entry(swp_entry_t entry)
{
return 0;
--- a/mm/filemap.c~mm-migrate-remove-cruft-from-migration_entry_waits
+++ a/mm/filemap.c
@@ -1362,8 +1362,6 @@ repeat:
/**
* migration_entry_wait_on_locked - Wait for a migration entry to be removed
* @entry: migration swap entry.
- * @ptep: mapped pte pointer. Will return with the ptep unmapped. Only required
- * for pte entries, pass NULL for pmd entries.
* @ptl: already locked ptl. This function will drop the lock.
*
* Wait for a migration entry referencing the given page to be removed. This is
@@ -1372,13 +1370,13 @@ repeat:
* should be called while holding the ptl for the migration entry referencing
* the page.
*
- * Returns after unmapping and unlocking the pte/ptl with pte_unmap_unlock().
+ * Returns after unlocking the ptl.
*
* This follows the same logic as folio_wait_bit_common() so see the comments
* there.
*/
-void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
- spinlock_t *ptl)
+void migration_entry_wait_on_locked(swp_entry_t entry, spinlock_t *ptl)
+ __releases(ptl)
{
struct wait_page_queue wait_page;
wait_queue_entry_t *wait = &wait_page.wait;
@@ -1412,10 +1410,7 @@ void migration_entry_wait_on_locked(swp_
* a valid reference to the page, and it must take the ptl to remove the
* migration entry. So the page is valid until the ptl is dropped.
*/
- if (ptep)
- pte_unmap_unlock(ptep, ptl);
- else
- spin_unlock(ptl);
+ spin_unlock(ptl);
for (;;) {
unsigned int flags;
--- a/mm/migrate.c~mm-migrate-remove-cruft-from-migration_entry_waits
+++ a/mm/migrate.c
@@ -296,14 +296,18 @@ void remove_migration_ptes(struct folio
* get to the page and wait until migration is finished.
* When we return from this function the fault will be retried.
*/
-void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
- spinlock_t *ptl)
+void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
+ unsigned long address)
{
+ spinlock_t *ptl;
+ pte_t *ptep;
pte_t pte;
swp_entry_t entry;
- spin_lock(ptl);
+ ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
pte = *ptep;
+ pte_unmap(ptep);
+
if (!is_swap_pte(pte))
goto out;
@@ -311,18 +315,10 @@ void __migration_entry_wait(struct mm_st
if (!is_migration_entry(entry))
goto out;
- migration_entry_wait_on_locked(entry, ptep, ptl);
+ migration_entry_wait_on_locked(entry, ptl);
return;
out:
- pte_unmap_unlock(ptep, ptl);
-}
-
-void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
- unsigned long address)
-{
- spinlock_t *ptl = pte_lockptr(mm, pmd);
- pte_t *ptep = pte_offset_map(pmd, address);
- __migration_entry_wait(mm, ptep, ptl);
+ spin_unlock(ptl);
}
#ifdef CONFIG_HUGETLB_PAGE
@@ -332,9 +328,9 @@ void migration_entry_wait(struct mm_stru
*
* This function will release the vma lock before returning.
*/
-void __migration_entry_wait_huge(struct vm_area_struct *vma,
- pte_t *ptep, spinlock_t *ptl)
+void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *ptep)
{
+ spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), vma->vm_mm, ptep);
pte_t pte;
hugetlb_vma_assert_locked(vma);
@@ -352,16 +348,9 @@ void __migration_entry_wait_huge(struct
* lock release in migration_entry_wait_on_locked().
*/
hugetlb_vma_unlock_read(vma);
- migration_entry_wait_on_locked(pte_to_swp_entry(pte), NULL, ptl);
+ migration_entry_wait_on_locked(pte_to_swp_entry(pte), ptl);
}
}
-
-void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte)
-{
- spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), vma->vm_mm, pte);
-
- __migration_entry_wait_huge(vma, pte, ptl);
-}
#endif
#ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
@@ -372,7 +361,7 @@ void pmd_migration_entry_wait(struct mm_
ptl = pmd_lock(mm, pmd);
if (!is_pmd_migration_entry(*pmd))
goto unlock;
- migration_entry_wait_on_locked(pmd_to_swp_entry(*pmd), NULL, ptl);
+ migration_entry_wait_on_locked(pmd_to_swp_entry(*pmd), ptl);
return;
unlock:
spin_unlock(ptl);
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
arm-allow-pte_offset_map-to-fail.patch
arm64-allow-pte_offset_map-to-fail.patch
arm64-hugetlb-pte_alloc_huge-pte_offset_huge.patch
ia64-hugetlb-pte_alloc_huge-pte_offset_huge.patch
m68k-allow-pte_offset_map-to-fail.patch
microblaze-allow-pte_offset_map-to-fail.patch
mips-update_mmu_cache-can-replace-__update_tlb.patch
mips-update_mmu_cache-can-replace-__update_tlb-fix.patch
parisc-add-pte_unmap-to-balance-get_ptep.patch
parisc-unmap_uncached_pte-use-pte_offset_kernel.patch
parisc-hugetlb-pte_alloc_huge-pte_offset_huge.patch
powerpc-kvmppc_unmap_free_pmd-pte_offset_kernel.patch
powerpc-allow-pte_offset_map-to-fail.patch
powerpc-hugetlb-pte_alloc_huge.patch
riscv-hugetlb-pte_alloc_huge-pte_offset_huge.patch
s390-allow-pte_offset_map_lock-to-fail.patch
s390-gmap-use-pte_unmap_unlock-not-spin_unlock.patch
sh-hugetlb-pte_alloc_huge-pte_offset_huge.patch
sparc-hugetlb-pte_alloc_huge-pte_offset_huge.patch
sparc-allow-pte_offset_map-to-fail.patch
sparc-iounit-and-iommu-use-pte_offset_kernel.patch
x86-allow-get_locked_pte-to-fail.patch
x86-sme_populate_pgd-use-pte_offset_kernel.patch
xtensa-add-pte_unmap-to-balance-pte_offset_map.patch
mm-use-pmdp_get_lockless-without-surplus-barrier.patch
mm-migrate-remove-cruft-from-migration_entry_waits.patch
mm-pgtable-kmap_local_page-instead-of-kmap_atomic.patch
mm-pgtable-allow-pte_offset_map-to-fail.patch
mm-filemap-allow-pte_offset_map_lock-to-fail.patch
mm-page_vma_mapped-delete-bogosity-in-page_vma_mapped_walk.patch
mm-page_vma_mapped-reformat-map_pte-with-less-indentation.patch
mm-page_vma_mapped-pte_offset_map_nolock-not-pte_lockptr.patch
mm-pagewalkers-action_again-if-pte_offset_map_lock-fails.patch
mm-pagewalk-walk_pte_range-allow-for-pte_offset_map.patch
mm-vmwgfx-simplify-pmd-pud-mapping-dirty-helpers.patch
mm-vmalloc-vmalloc_to_page-use-pte_offset_kernel.patch
mm-hmm-retry-if-pte_offset_map-fails.patch
mm-userfaultfd-retry-if-pte_offset_map-fails.patch
mm-userfaultfd-allow-pte_offset_map_lock-to-fail.patch
mm-debug_vm_pgtablepage_table_check-warn-pte-map-fails.patch
mm-various-give-up-if-pte_offset_map-fails.patch
mm-mprotect-delete-pmd_none_or_clear_bad_unless_trans_huge.patch
mm-mremap-retry-if-either-pte_offset_map_lock-fails.patch
mm-madvise-clean-up-pte_offset_map_lock-scans.patch
mm-madvise-clean-up-force_shm_swapin_readahead.patch
mm-swapoff-allow-pte_offset_map-to-fail.patch
mm-mglru-allow-pte_offset_map_nolock-to-fail.patch
mm-migrate_device-allow-pte_offset_map_lock-to-fail.patch
mm-gup-remove-foll_split_pmd-use-of-pmd_trans_unstable.patch
mm-huge_memory-split-huge-pmd-under-one-pte_offset_map.patch
mm-khugepaged-allow-pte_offset_map-to-fail.patch
mm-memory-allow-pte_offset_map-to-fail.patch
mm-memory-handle_pte_fault-use-pte_offset_map_nolock.patch
mm-pgtable-delete-pmd_trans_unstable-and-friends.patch
mm-swap-swap_vma_readahead-do-the-pte_offset_map.patch
perf-core-allow-pte_offset_map-to-fail.patch
