From: Minchan Kim <minchan@xxxxxxxxxx> Subject: mm: replace migrate_[prep|finish] with lru_cache_[disable|enable] Currently, migrate_[prep|finish] is merely a wrapper of lru_cache_[disable|enable]. There is not much to gain from having additional abstraction. Use lru_cache_[disable|enable] instead of migrate_[prep|finish], which would be more descriptive. note: migrate_prep_local in compaction.c changed into lru_add_drain to avoid CPU schedule cost with involving many other CPUs to keep old behavior. Link: https://lkml.kernel.org/r/20210319175127.886124-2-minchan@xxxxxxxxxx Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> Acked-by: Michal Hocko <mhocko@xxxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> Cc: Chris Goldsworthy <cgoldswo@xxxxxxxxxxxxxx> Cc: John Dias <joaodias@xxxxxxxxxx> Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> Cc: Oliver Sang <oliver.sang@xxxxxxxxx> Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/migrate.h | 7 ------- mm/compaction.c | 3 ++- mm/mempolicy.c | 8 ++++---- mm/migrate.c | 28 ++-------------------------- mm/page_alloc.c | 4 ++-- 5 files changed, 10 insertions(+), 40 deletions(-) --- a/include/linux/migrate.h~mm-replace-migrate_-with-lru_cache_ +++ a/include/linux/migrate.h @@ -45,9 +45,6 @@ extern struct page *alloc_migration_targ extern int isolate_movable_page(struct page *page, isolate_mode_t mode); extern void putback_movable_page(struct page *page); -extern void migrate_prep(void); -extern void migrate_finish(void); -extern void migrate_prep_local(void); extern void migrate_page_states(struct page *newpage, struct page *page); extern void migrate_page_copy(struct page *newpage, struct page *page); extern int migrate_huge_page_move_mapping(struct address_space *mapping, @@ -67,10 +64,6 @@ static inline struct page *alloc_migrati static inline int isolate_movable_page(struct page *page, isolate_mode_t mode) { return -EBUSY; } -static inline int migrate_prep(void) { return -ENOSYS; } -static inline int migrate_finish(void) { return -ENOSYS; } -static inline int migrate_prep_local(void) { return -ENOSYS; } - static inline void migrate_page_states(struct page *newpage, struct page *page) { } --- a/mm/compaction.c~mm-replace-migrate_-with-lru_cache_ +++ a/mm/compaction.c @@ -2354,7 +2354,8 @@ compact_zone(struct compact_control *cc, trace_mm_compaction_begin(start_pfn, cc->migrate_pfn, cc->free_pfn, end_pfn, sync); - migrate_prep_local(); + /* lru_add_drain_all could be expensive with involving other CPUs */ + lru_add_drain(); while ((ret = compact_finished(cc)) == COMPACT_CONTINUE) { int err; --- a/mm/mempolicy.c~mm-replace-migrate_-with-lru_cache_ +++ a/mm/mempolicy.c @@ -1124,7 +1124,7 @@ int do_migrate_pages(struct mm_struct *m int err = 0; nodemask_t tmp; - migrate_prep(); + lru_cache_disable(); mmap_read_lock(mm); @@ -1209,7 +1209,7 @@ int do_migrate_pages(struct mm_struct *m } mmap_read_unlock(mm); - migrate_finish(); + lru_cache_enable(); if (err < 0) return err; return busy; @@ -1325,7 +1325,7 @@ static long do_mbind(unsigned long start if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) { - migrate_prep(); + lru_cache_disable(); } { NODEMASK_SCRATCH(scratch); @@ -1374,7 +1374,7 @@ up_out: mpol_out: mpol_put(new); if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) - migrate_finish(); + lru_cache_enable(); return err; } --- a/mm/migrate.c~mm-replace-migrate_-with-lru_cache_ +++ a/mm/migrate.c @@ -57,30 +57,6 @@ #include "internal.h" -/* - * migrate_prep() needs to be called before we start compiling a list of pages - * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is - * undesirable, use migrate_prep_local() - */ -void migrate_prep(void) -{ - /* - * Clear the LRU lists so pages can be isolated. - */ - lru_cache_disable(); -} - -void migrate_finish(void) -{ - lru_cache_enable(); -} - -/* Do the necessary work of migrate_prep but not if it involves other CPUs */ -void migrate_prep_local(void) -{ - lru_add_drain(); -} - int isolate_movable_page(struct page *page, isolate_mode_t mode) { struct address_space *mapping; @@ -1771,7 +1747,7 @@ static int do_pages_move(struct mm_struc int start, i; int err = 0, err1; - migrate_prep(); + lru_cache_disable(); for (i = start = 0; i < nr_pages; i++) { const void __user *p; @@ -1840,7 +1816,7 @@ out_flush: if (err >= 0) err = err1; out: - migrate_finish(); + lru_cache_enable(); return err; } --- a/mm/page_alloc.c~mm-replace-migrate_-with-lru_cache_ +++ a/mm/page_alloc.c @@ -8681,7 +8681,7 @@ static int __alloc_contig_migrate_range( .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, }; - migrate_prep(); + lru_cache_disable(); while (pfn < end || !list_empty(&cc->migratepages)) { if (fatal_signal_pending(current)) { @@ -8716,7 +8716,7 @@ static int __alloc_contig_migrate_range( break; } - migrate_finish(); + lru_cache_enable(); if (ret < 0) { alloc_contig_dump_pages(&cc->migratepages); putback_movable_pages(&cc->migratepages); _
