Introduce MIGRATE_ASYNC_NONTEMPORAL to migrate cold folios using non-temporal stores, avoiding CPU cache pollution.
Existing callers check "mode == MIGRATE_ASYNC" directly, which would cause new asynchronous modes to fall back to synchronous handling. Introduce migrate_is_async() and update callers across compaction, NFS, and migration. In __migrate_folio(), invoke folio_mc_copy_nt() when the migration mode is MIGRATE_ASYNC_NONTEMPORAL. Suggested-by: Alirad Malek <[email protected]> Suggested-by: Dimitrios Palyvos-Giannas <[email protected]> Signed-off-by: Huan Nguyen <[email protected]> --- fs/nfs/write.c | 2 +- include/linux/migrate.h | 5 +++++ include/linux/migrate_mode.h | 1 + include/trace/events/migrate.h | 1 + mm/compaction.c | 18 +++++++++--------- mm/migrate.c | 29 ++++++++++++++++++----------- 6 files changed, 35 insertions(+), 21 deletions(-) diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 0b42d31f7a75..ad28ff48e541 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -2128,7 +2128,7 @@ int nfs_migrate_folio(struct address_space *mapping, struct folio *dst, } if (folio_test_private_2(src)) { /* [DEPRECATED] */ - if (mode == MIGRATE_ASYNC) + if (migrate_is_async(mode)) return -EBUSY; folio_wait_private_2(src); } diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 78424b3824c2..188f9d891a0a 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -51,6 +51,11 @@ struct movable_operations { /* Defined in mm/debug.c: */ extern const char *migrate_reason_names[MR_TYPES]; +static inline bool migrate_is_async(enum migrate_mode mode) +{ + return mode == MIGRATE_ASYNC || mode == MIGRATE_ASYNC_NONTEMPORAL; +} + #ifdef CONFIG_MIGRATION void putback_movable_pages(struct list_head *l); diff --git a/include/linux/migrate_mode.h b/include/linux/migrate_mode.h index 05102d4d2490..fd752fddc972 100644 --- a/include/linux/migrate_mode.h +++ b/include/linux/migrate_mode.h @@ -12,6 +12,7 @@ enum migrate_mode { MIGRATE_ASYNC, MIGRATE_SYNC_LIGHT, MIGRATE_SYNC, + MIGRATE_ASYNC_NONTEMPORAL, }; enum migrate_reason { diff --git a/include/trace/events/migrate.h b/include/trace/events/migrate.h index 15ee2ef201b5..0bb2444211af 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_NONTEMPORAL, "MIGRATE_ASYNC_NONTEMPORAL") \ EM( MIGRATE_SYNC_LIGHT, "MIGRATE_SYNC_LIGHT") \ EMe(MIGRATE_SYNC, "MIGRATE_SYNC") diff --git a/mm/compaction.c b/mm/compaction.c index f1b2060eb201..c11739e6891f 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -445,7 +445,7 @@ 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_is_async(cc->mode) && pfn > zone->compact_cached_migrate_pfn[1]) zone->compact_cached_migrate_pfn[1] = pfn; } @@ -508,7 +508,7 @@ 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_is_async(cc->mode) && !cc->contended) { if (spin_trylock_irqsave(lock, *flags)) return true; @@ -882,7 +882,7 @@ 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_is_async(cc->mode)) return -EAGAIN; reclaim_throttle(pgdat, VMSCAN_THROTTLE_ISOLATED); @@ -893,7 +893,7 @@ 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_is_async(cc->mode)) { skip_on_failure = true; next_skip_pfn = block_end_pfn(low_pfn, cc->order); } @@ -1409,7 +1409,7 @@ static bool suitable_migration_source(struct compact_control *cc, * allocator fallbacks. For non-movable requests, this helps a * lot, as they can finally scan movable blocks. */ - if (cc->mode != MIGRATE_ASYNC) + if (!migrate_is_async(cc->mode)) return true; /* @@ -1514,7 +1514,7 @@ 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_is_async(cc->mode)) return; /* Pageblock boundaries */ @@ -1753,7 +1753,7 @@ 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_is_async(cc->mode) ? COMPACT_CLUSTER_MAX : 1; /* * Isolate free pages until enough are available to migrate the @@ -2565,7 +2565,7 @@ 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_is_async(cc->mode); bool update_cached; unsigned int nr_succeeded = 0, nr_migratepages; int order; @@ -2588,7 +2588,7 @@ 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_is_async(cc->mode), !cc->direct_compaction); if (ret != COMPACT_CONTINUE) return ret; diff --git a/mm/migrate.c b/mm/migrate.c index 7bdcdb57652f..18470de10857 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -876,9 +876,15 @@ static int __migrate_folio(struct address_space *mapping, struct folio *dst, if (folio_ref_count(src) != expected_count) return -EAGAIN; - rc = folio_mc_copy(dst, src); - if (unlikely(rc)) - return rc; + if (mode == MIGRATE_ASYNC_NONTEMPORAL) { + rc = folio_mc_copy_nt(dst, src); + if (unlikely(rc)) + return rc; + } else { + rc = folio_mc_copy(dst, src); + if (unlikely(rc)) + return rc; + } rc = __folio_migrate_mapping(mapping, dst, src, expected_count); if (rc) @@ -921,7 +927,7 @@ static bool buffer_migrate_lock_buffers(struct buffer_head *head, do { if (!trylock_buffer(bh)) { - if (mode == MIGRATE_ASYNC) + if (migrate_is_async(mode)) goto unlock; if (mode == MIGRATE_SYNC_LIGHT && !buffer_uptodate(bh)) goto unlock; @@ -1229,7 +1235,7 @@ static int migrate_folio_unmap(new_folio_t get_new_folio, dst->migrate_info = 0; if (!folio_trylock(src)) { - if (mode == MIGRATE_ASYNC) + if (migrate_is_async(mode)) goto out; /* @@ -1334,7 +1340,7 @@ 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_is_async(mode) ? TTU_BATCH_FLUSH : 0); old_folio_state |= FOLIO_WAS_MAPPED; } @@ -1592,7 +1598,7 @@ static inline int try_split_folio(struct folio *folio, struct list_head *split_f { int rc; - if (mode == MIGRATE_ASYNC) { + if (migrate_is_async(mode)) { if (!folio_trylock(folio)) return -EAGAIN; } else { @@ -1826,7 +1832,7 @@ 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_is_async(mode) && !list_empty(from) && !list_is_singular(from)); for (pass = 0; pass < nr_pass && retry; pass++) { @@ -2134,7 +2140,7 @@ 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_is_async(mode)) rc = migrate_pages_batch(&folios, get_new_folio, put_new_folio, private, mode, reason, &ret_folios, &split_folios, &stats, @@ -2156,8 +2162,9 @@ int migrate_pages(struct list_head *from, new_folio_t get_new_folio, * with minimal effort, force MIGRATE_ASYNC mode and retry once. */ migrate_pages_batch(&split_folios, get_new_folio, - put_new_folio, private, MIGRATE_ASYNC, reason, - &ret_folios, NULL, &stats, 1); + put_new_folio, private, + migrate_is_async(mode) ? mode : MIGRATE_ASYNC, + reason, &ret_folios, NULL, &stats, 1); list_splice_tail_init(&split_folios, &ret_folios); } rc_gather += rc; -- 2.56.0.398.g882cbad275-goog
