The patch titled
Subject: mm/migrate.c: Rework migration_entry_wait() to not take a pageref
has been added to the -mm tree. Its filename is
mm-migratec-rework-migration_entry_wait-to-not-take-a-pageref-v5.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-migratec-rework-migration_entry_wait-to-not-take-a-pageref-v5.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-migratec-rework-migration_entry_wait-to-not-take-a-pageref-v5.patch
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------------------------------------------------------
From: Alistair Popple <apopple@xxxxxxxxxx>
Subject: mm/migrate.c: Rework migration_entry_wait() to not take a pageref
- Documentation/comment fixes from David H
- Added David's Acked-by
- Changed functions to take swap entries instead of struct pages as
suggested by Matthew W
Link: https://lkml.kernel.org/r/20211213033848.1973946-1-apopple@xxxxxxxxxx
Signed-off-by: Alistair Popple <apopple@xxxxxxxxxx>
Acked-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: John Hubbard <jhubbard@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/migrate.h | 2 +-
mm/filemap.c | 11 +++++++----
mm/migrate.c | 10 ++--------
3 files changed, 10 insertions(+), 13 deletions(-)
--- a/include/linux/migrate.h~mm-migratec-rework-migration_entry_wait-to-not-take-a-pageref-v5
+++ a/include/linux/migrate.h
@@ -40,7 +40,7 @@ extern int migrate_huge_page_move_mappin
struct page *newpage, struct page *page);
extern int migrate_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page, int extra_count);
-void migration_entry_wait_on_locked(struct folio *folio, pte_t *ptep,
+void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
spinlock_t *ptl);
void folio_migrate_flags(struct folio *newfolio, struct folio *folio);
void folio_migrate_copy(struct folio *newfolio, struct folio *folio);
--- a/mm/filemap.c~mm-migratec-rework-migration_entry_wait-to-not-take-a-pageref-v5
+++ a/mm/filemap.c
@@ -21,6 +21,7 @@
#include <linux/gfp.h>
#include <linux/mm.h>
#include <linux/swap.h>
+#include <linux/swapops.h>
#include <linux/mman.h>
#include <linux/pagemap.h>
#include <linux/file.h>
@@ -1430,8 +1431,9 @@ repeat:
#ifdef CONFIG_MIGRATION
/**
* migration_entry_wait_on_locked - Wait for a migration entry to be removed
- * @folio: folio referenced by the migration entry.
- * @ptep: mapped pte pointer. This function will return with the ptep unmapped.
+ * @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
@@ -1442,10 +1444,10 @@ repeat:
*
* Returns after unmapping and unlocking the pte/ptl with pte_unmap_unlock().
*
- * This follows the same logic as wait_on_page_bit_common() so see the comments
+ * This follows the same logic as folio_wait_bit_common() so see the comments
* there.
*/
-void migration_entry_wait_on_locked(struct folio *folio, pte_t *ptep,
+void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep,
spinlock_t *ptl)
{
struct wait_page_queue wait_page;
@@ -1454,6 +1456,7 @@ void migration_entry_wait_on_locked(stru
bool delayacct = false;
unsigned long pflags;
wait_queue_head_t *q;
+ struct folio *folio = page_folio(pfn_swap_entry_to_page(entry));
q = folio_waitqueue(folio);
if (!folio_test_uptodate(folio) && folio_test_workingset(folio)) {
--- a/mm/migrate.c~mm-migratec-rework-migration_entry_wait-to-not-take-a-pageref-v5
+++ a/mm/migrate.c
@@ -291,7 +291,6 @@ void __migration_entry_wait(struct mm_st
{
pte_t pte;
swp_entry_t entry;
- struct page *page;
spin_lock(ptl);
pte = *ptep;
@@ -302,10 +301,7 @@ void __migration_entry_wait(struct mm_st
if (!is_migration_entry(entry))
goto out;
- page = pfn_swap_entry_to_page(entry);
- page = compound_head(page);
-
- migration_entry_wait_on_locked(page_folio(page), ptep, ptl);
+ migration_entry_wait_on_locked(entry, ptep, ptl);
return;
out:
pte_unmap_unlock(ptep, ptl);
@@ -330,13 +326,11 @@ void migration_entry_wait_huge(struct vm
void pmd_migration_entry_wait(struct mm_struct *mm, pmd_t *pmd)
{
spinlock_t *ptl;
- struct page *page;
ptl = pmd_lock(mm, pmd);
if (!is_pmd_migration_entry(*pmd))
goto unlock;
- page = pfn_swap_entry_to_page(pmd_to_swp_entry(*pmd));
- migration_entry_wait_on_locked(page_folio(page), NULL, ptl);
+ migration_entry_wait_on_locked(pmd_to_swp_entry(*pmd), NULL, ptl);
return;
unlock:
spin_unlock(ptl);
_
Patches currently in -mm which might be from apopple@xxxxxxxxxx are
mm-migratec-rework-migration_entry_wait-to-not-take-a-pageref.patch
mm-migratec-rework-migration_entry_wait-to-not-take-a-pageref-v5.patch
mm-hmmc-allow-vm_mixedmap-to-work-with-hmm_range_fault.patch
