Commit 0cb8fd4d authored by Hugh Dickins's avatar Hugh Dickins Committed by Andrew Morton
Browse files

mm/migrate: remove cruft from migration_entry_wait()s 

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@google.com


Signed-off-by: default avatarHugh Dickins <hughd@google.com>
Reviewed-by: default avatarAlistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Steven Price <steven.price@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zack Rusin <zackr@vmware.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 26e1a0c3

include/linux/migrate.h

+2 −2
Original line number Diff line number Diff line
@@ -75,8 +75,8 @@ bool isolate_movable_page(struct page *page, isolate_mode_t mode); 


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,

include/linux/swapops.h

+3 −14
Original line number Diff line number Diff line
@@ -332,15 +332,9 @@ static inline bool is_migration_entry_dirty(swp_entry_t entry) 
	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_entry_t 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 */

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;

mm/filemap.c

+4 −9
Original line number Diff line number Diff line
@@ -1362,8 +1362,6 @@ static inline int folio_wait_bit_common(struct folio *folio, int bit_nr, 
/**

 * 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 @@ static inline int folio_wait_bit_common(struct folio *folio, int bit_nr, 
 * 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;
@@ -1412,9 +1410,6 @@ void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep, 
	 * 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);



	for (;;) {

mm/migrate.c

+13 −24
Original line number Diff line number Diff line
@@ -296,14 +296,18 @@ void remove_migration_ptes(struct folio *src, struct folio *dst, bool locked) 
 * 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_struct *mm, pte_t *ptep, 
	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_struct *mm, pmd_t *pmd, 
 *

 * 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);
@@ -352,15 +348,8 @@ void __migration_entry_wait_huge(struct vm_area_struct *vma, 
		 * 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
@@ -372,7 +361,7 @@ void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd) 
	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);