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mm/migrate: use migrate_info field instead of private

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Add an unsigned long migrate_info member to the struct folio union and use
it to store migration state (anon_vma pointer and FOLIO_WAS_* markers)
instead of using folio->private.  While at it, switch to bitwise OR.

No functional change.

[rdunlap@infradead.org: add missing kernel-doc for @migrate_info]
  Link: https://lore.kernel.org/20260717022146.1290242-1-rdunlap@infradead.org
Link: https://lore.kernel.org/20260701-migrate-cleanups-prep-v2-3-d9e8f17130b1@amd.com
Signed-off-by: Shivank Garg <shivankg@amd.com>
Suggested-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Reviewed-by: Huang Ying <ying.huang@linux.alibaba.com>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: SJ Park <sj@kernel.org>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Gregory Price <gourry@gourry.net>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Shivank Garg
2026-07-01 05:17:22 +00:00
committed by Andrew Morton
parent 8d76257715
commit 3dd5a633a0
2 changed files with 10 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
include/linux/mm_types.h
View File

@@ -368,6 +368,8 @@ typedef unsigned short mm_id_t;
* dax_associate_entry.
* @private: Filesystem per-folio data (see folio_attach_private()).
* @swap: Used for swp_entry_t if folio_test_swapcache().
* @migrate_info: Stores migration state (anon_vma pointer and
* FOLIO_WAS_* markers).
* @_mapcount: Do not access this member directly. Use folio_mapcount() to
* find out how many times this folio is mapped by userspace.
* @_refcount: Do not access this member directly. Use folio_ref_count()
@@ -427,6 +429,7 @@ struct folio {
union {
void *private;
swp_entry_t swap;
unsigned long migrate_info;
};
atomic_t _mapcount;
atomic_t _refcount;

14
mm/migrate.c
View File

@@ -1130,7 +1130,7 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
}
/*
* To record some information during migration, we use unused private
* To record some information during migration, we use the migrate_info
* field of struct folio of the newly allocated destination folio.
* This is safe because nobody is using it except us.
*/
@@ -1143,17 +1143,17 @@ enum {
static void __migrate_folio_record(struct folio *dst,
int old_folio_state, struct anon_vma *anon_vma)
{
dst->private = (void *)anon_vma + old_folio_state;
dst->migrate_info = (unsigned long)anon_vma | old_folio_state;
}
static void __migrate_folio_extract(struct folio *dst,
int *old_folio_state, struct anon_vma **anon_vmap)
{
unsigned long private = (unsigned long)dst->private;
unsigned long info = dst->migrate_info;
*anon_vmap = (struct anon_vma *)(private & ~FOLIO_OLD_STATES);
*old_folio_state = private & FOLIO_OLD_STATES;
dst->private = NULL;
*anon_vmap = (struct anon_vma *)(info & ~FOLIO_OLD_STATES);
*old_folio_state = info & FOLIO_OLD_STATES;
dst->migrate_info = 0;
}
/* Restore the source folio to the original state upon failure */
@@ -1214,7 +1214,7 @@ static int migrate_folio_unmap(new_folio_t get_new_folio,
return -ENOMEM;
*dstp = dst;
dst->private = NULL;
dst->migrate_info = 0;
if (!folio_trylock(src)) {
if (mode == MIGRATE_ASYNC)