[PATCH RFC 2/3] mm: new migrate_mode flag for async using non-temporal stores
From: Yiannis Nikolakopoulos
Date: Tue May 26 2026 - 07:40:36 EST
From: Alirad Malek <alirad.malek@xxxxxxxxxxx>
In preparation for the following patch, add a new migrate_mode which is
still async but will use non-temporal stores. Add a helper function
that checks for both async modes and replace all plain checks of
MIGRATE_ASYNC.
Signed-off-by: Alirad Malek <alirad.malek@xxxxxxxxxxx>
Co-developed-by: Yiannis Nikolakopoulos <yiannis.nikolakop@xxxxxxxxx>
Signed-off-by: Yiannis Nikolakopoulos <yiannis.nikolakop@xxxxxxxxx>
---
fs/nfs/write.c | 2 +-
include/linux/migrate_mode.h | 9 +++++++++
include/trace/events/migrate.h | 1 +
mm/compaction.c | 18 +++++++++---------
mm/migrate.c | 12 ++++++------
5 files changed, 26 insertions(+), 16 deletions(-)
diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 1ed4b3590b1a..beae4441e080 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -2119,7 +2119,7 @@ int nfs_migrate_folio(struct address_space *mapping, struct folio *dst,
}
if (folio_test_private_2(src)) { /* [DEPRECATED] */
- if (mode == MIGRATE_ASYNC)
+ if (migrate_mode_is_async(mode))
return -EBUSY;
folio_wait_private_2(src);
}
diff --git a/include/linux/migrate_mode.h b/include/linux/migrate_mode.h
index 265c4328b36a..f7186e705b48 100644
--- a/include/linux/migrate_mode.h
+++ b/include/linux/migrate_mode.h
@@ -3,6 +3,8 @@
#define MIGRATE_MODE_H_INCLUDED
/*
* MIGRATE_ASYNC means never block
+ * MIGRATE_ASYNC_NON_TEMPORAL_STORES means never block and use non-temporal
+ * stores if supported by the architecture
* MIGRATE_SYNC_LIGHT in the current implementation means to allow blocking
* on most operations but not ->writepage as the potential stall time
* is too significant
@@ -10,10 +12,17 @@
*/
enum migrate_mode {
MIGRATE_ASYNC,
+ MIGRATE_ASYNC_NON_TEMPORAL_STORES,
MIGRATE_SYNC_LIGHT,
MIGRATE_SYNC,
};
+static inline bool migrate_mode_is_async(enum migrate_mode mode)
+{
+ return mode == MIGRATE_ASYNC ||
+ mode == MIGRATE_ASYNC_NON_TEMPORAL_STORES;
+}
+
enum migrate_reason {
MR_COMPACTION,
MR_MEMORY_FAILURE,
diff --git a/include/trace/events/migrate.h b/include/trace/events/migrate.h
index cd01dd7b3640..e493207a3f46 100644
--- a/include/trace/events/migrate.h
+++ b/include/trace/events/migrate.h
@@ -9,6 +9,7 @@
#define MIGRATE_MODE \
EM( MIGRATE_ASYNC, "MIGRATE_ASYNC") \
+ EM(MIGRATE_ASYNC_NON_TEMPORAL_STORES, "MIGRATE_ASYNC_NON_TEMPORAL_STORES") \
EM( MIGRATE_SYNC_LIGHT, "MIGRATE_SYNC_LIGHT") \
EMe(MIGRATE_SYNC, "MIGRATE_SYNC")
diff --git a/mm/compaction.c b/mm/compaction.c
index 1e8f8eca318c..cd26781b7376 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -444,7 +444,7 @@ static void update_cached_migrate(struct compact_control *cc, unsigned long pfn)
/* Update where async and sync compaction should restart */
if (pfn > zone->compact_cached_migrate_pfn[0])
zone->compact_cached_migrate_pfn[0] = pfn;
- if (cc->mode != MIGRATE_ASYNC &&
+ if (!migrate_mode_is_async(cc->mode) &&
pfn > zone->compact_cached_migrate_pfn[1])
zone->compact_cached_migrate_pfn[1] = pfn;
}
@@ -507,7 +507,7 @@ static bool compact_lock_irqsave(spinlock_t *lock, unsigned long *flags,
__acquires(lock)
{
/* Track if the lock is contended in async mode */
- if (cc->mode == MIGRATE_ASYNC && !cc->contended) {
+ if (migrate_mode_is_async(cc->mode) && !cc->contended) {
if (spin_trylock_irqsave(lock, *flags))
return true;
@@ -864,7 +864,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
return -EAGAIN;
/* async migration should just abort */
- if (cc->mode == MIGRATE_ASYNC)
+ if (migrate_mode_is_async(cc->mode))
return -EAGAIN;
reclaim_throttle(pgdat, VMSCAN_THROTTLE_ISOLATED);
@@ -875,7 +875,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
cond_resched();
- if (cc->direct_compaction && (cc->mode == MIGRATE_ASYNC)) {
+ if (cc->direct_compaction && migrate_mode_is_async(cc->mode)) {
skip_on_failure = true;
next_skip_pfn = block_end_pfn(low_pfn, cc->order);
}
@@ -1364,7 +1364,7 @@ static bool suitable_migration_source(struct compact_control *cc,
if (pageblock_skip_persistent(page))
return false;
- if ((cc->mode != MIGRATE_ASYNC) || !cc->direct_compaction)
+ if (!migrate_mode_is_async(cc->mode) || !cc->direct_compaction)
return true;
block_mt = get_pageblock_migratetype(page);
@@ -1465,7 +1465,7 @@ fast_isolate_around(struct compact_control *cc, unsigned long pfn)
return;
/* Minimise scanning during async compaction */
- if (cc->direct_compaction && cc->mode == MIGRATE_ASYNC)
+ if (cc->direct_compaction && migrate_mode_is_async(cc->mode))
return;
/* Pageblock boundaries */
@@ -1705,7 +1705,7 @@ static void isolate_freepages(struct compact_control *cc)
block_end_pfn = min(block_start_pfn + pageblock_nr_pages,
zone_end_pfn(zone));
low_pfn = pageblock_end_pfn(cc->migrate_pfn);
- stride = cc->mode == MIGRATE_ASYNC ? COMPACT_CLUSTER_MAX : 1;
+ stride = migrate_mode_is_async(cc->mode) ? COMPACT_CLUSTER_MAX : 1;
/*
* Isolate free pages until enough are available to migrate the
@@ -2514,7 +2514,7 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
unsigned long start_pfn = cc->zone->zone_start_pfn;
unsigned long end_pfn = zone_end_pfn(cc->zone);
unsigned long last_migrated_pfn;
- const bool sync = cc->mode != MIGRATE_ASYNC;
+ const bool sync = !migrate_mode_is_async(cc->mode);
bool update_cached;
unsigned int nr_succeeded = 0, nr_migratepages;
int order;
@@ -2537,7 +2537,7 @@ compact_zone(struct compact_control *cc, struct capture_control *capc)
ret = compaction_suit_allocation_order(cc->zone, cc->order,
cc->highest_zoneidx,
cc->alloc_flags,
- cc->mode == MIGRATE_ASYNC,
+ migrate_mode_is_async(cc->mode),
!cc->direct_compaction);
if (ret != COMPACT_CONTINUE)
return ret;
diff --git a/mm/migrate.c b/mm/migrate.c
index 2c3d489ecf51..ff6cf50e7b0b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -907,7 +907,7 @@ static bool buffer_migrate_lock_buffers(struct buffer_head *head,
do {
if (!trylock_buffer(bh)) {
- if (mode == MIGRATE_ASYNC)
+ if (migrate_mode_is_async(mode))
goto unlock;
if (mode == MIGRATE_SYNC_LIGHT && !buffer_uptodate(bh))
goto unlock;
@@ -1220,7 +1220,7 @@ static int migrate_folio_unmap(new_folio_t get_new_folio,
dst->private = NULL;
if (!folio_trylock(src)) {
- if (mode == MIGRATE_ASYNC)
+ if (migrate_mode_is_async(mode))
goto out;
/*
@@ -1325,7 +1325,7 @@ static int migrate_folio_unmap(new_folio_t get_new_folio,
/* Establish migration ptes */
VM_BUG_ON_FOLIO(folio_test_anon(src) &&
!folio_test_ksm(src) && !anon_vma, src);
- try_to_migrate(src, mode == MIGRATE_ASYNC ? TTU_BATCH_FLUSH : 0);
+ try_to_migrate(src, migrate_mode_is_async(mode) ? TTU_BATCH_FLUSH : 0);
old_page_state |= PAGE_WAS_MAPPED;
}
@@ -1565,7 +1565,7 @@ static inline int try_split_folio(struct folio *folio, struct list_head *split_f
{
int rc;
- if (mode == MIGRATE_ASYNC) {
+ if (migrate_mode_is_async(mode)) {
if (!folio_trylock(folio))
return -EAGAIN;
} else {
@@ -1799,7 +1799,7 @@ static int migrate_pages_batch(struct list_head *from,
LIST_HEAD(dst_folios);
bool nosplit = (reason == MR_NUMA_MISPLACED);
- VM_WARN_ON_ONCE(mode != MIGRATE_ASYNC &&
+ VM_WARN_ON_ONCE(!migrate_mode_is_async(mode) &&
!list_empty(from) && !list_is_singular(from));
for (pass = 0; pass < nr_pass && retry; pass++) {
@@ -2107,7 +2107,7 @@ int migrate_pages(struct list_head *from, new_folio_t get_new_folio,
list_cut_before(&folios, from, &folio2->lru);
else
list_splice_init(from, &folios);
- if (mode == MIGRATE_ASYNC)
+ if (migrate_mode_is_async(mode))
rc = migrate_pages_batch(&folios, get_new_folio, put_new_folio,
private, mode, reason, &ret_folios,
&split_folios, &stats,
--
2.43.0