| Message ID | 20210310161429.399432-1-minchan@kernel.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3,1/3] mm: replace migrate_prep with lru_add_drain_all | expand |
On Wed 10-03-21 08:14:27, Minchan Kim wrote: > Currently, migrate_prep is merely a wrapper of lru_cache_add_all. > There is not much to gain from having additional abstraction. > > Use lru_add_drain_all instead of migrate_prep, 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 > keep old behavior. > > Signed-off-by: Minchan Kim <minchan@kernel.org> Acked-by: Michal Hocko <mhocko@suse.com> Btw. that migrate_prep_local likely needs revisiting. I really fail to see why it is useful. It looks like just in case thing to me. If it is needed then the comment should be describing why. Something for a separate patch though. > --- > include/linux/migrate.h | 5 ----- > mm/compaction.c | 3 ++- > mm/mempolicy.c | 4 ++-- > mm/migrate.c | 24 +----------------------- > mm/page_alloc.c | 2 +- > mm/swap.c | 5 +++++ > 6 files changed, 11 insertions(+), 32 deletions(-) > > diff --git a/include/linux/migrate.h b/include/linux/migrate.h > index 3a389633b68f..6155d97ec76c 100644 > --- a/include/linux/migrate.h > +++ b/include/linux/migrate.h > @@ -45,8 +45,6 @@ extern struct page *alloc_migration_target(struct page *page, unsigned long priv > 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_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, > @@ -66,9 +64,6 @@ static inline struct page *alloc_migration_target(struct page *page, > 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_prep_local(void) { return -ENOSYS; } > - > static inline void migrate_page_states(struct page *newpage, struct page *page) > { > } > diff --git a/mm/compaction.c b/mm/compaction.c > index e04f4476e68e..3be017ececc0 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -2319,7 +2319,8 @@ compact_zone(struct compact_control *cc, struct capture_control *capc) > 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; > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index ab51132547b8..fc024e97be37 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -1124,7 +1124,7 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, > int err = 0; > nodemask_t tmp; > > - migrate_prep(); > + lru_add_drain_all(); > > mmap_read_lock(mm); > > @@ -1323,7 +1323,7 @@ static long do_mbind(unsigned long start, unsigned long len, > > if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) { > > - migrate_prep(); > + lru_add_drain_all(); > } > { > NODEMASK_SCRATCH(scratch); > diff --git a/mm/migrate.c b/mm/migrate.c > index 62b81d5257aa..45f925e10f5a 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -57,28 +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. > - * Note that pages may be moved off the LRU after we have > - * drained them. Those pages will fail to migrate like other > - * pages that may be busy. > - */ > - lru_add_drain_all(); > -} > - > -/* 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; > @@ -1769,7 +1747,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > int start, i; > int err = 0, err1; > > - migrate_prep(); > + lru_add_drain_all(); > > for (i = start = 0; i < nr_pages; i++) { > const void __user *p; > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 2e8348936df8..f05a8db741ca 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -8467,7 +8467,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc, > .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, > }; > > - migrate_prep(); > + lru_add_drain_all(); > > while (pfn < end || !list_empty(&cc->migratepages)) { > if (fatal_signal_pending(current)) { > diff --git a/mm/swap.c b/mm/swap.c > index 31b844d4ed94..441d1ae1f285 100644 > --- a/mm/swap.c > +++ b/mm/swap.c > @@ -729,6 +729,11 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy) > } > > /* > + * lru_add_drain_all() usually needs to be called before we start compiling > + * a list of pages to be migrated using isolate_lru_page(). Note that pages > + * may be moved off the LRU after we have drained them. Those pages will > + * fail to migrate like other pages that may be busy. > + * > * Doesn't need any cpu hotplug locking because we do rely on per-cpu > * kworkers being shut down before our page_alloc_cpu_dead callback is > * executed on the offlined cpu. > -- > 2.30.1.766.gb4fecdf3b7-goog
On 10.03.21 17:14, Minchan Kim wrote: > Currently, migrate_prep is merely a wrapper of lru_cache_add_all. > There is not much to gain from having additional abstraction. > > Use lru_add_drain_all instead of migrate_prep, 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 > keep old behavior. > > Signed-off-by: Minchan Kim <minchan@kernel.org> > --- > include/linux/migrate.h | 5 ----- > mm/compaction.c | 3 ++- > mm/mempolicy.c | 4 ++-- > mm/migrate.c | 24 +----------------------- > mm/page_alloc.c | 2 +- > mm/swap.c | 5 +++++ > 6 files changed, 11 insertions(+), 32 deletions(-) > > diff --git a/include/linux/migrate.h b/include/linux/migrate.h > index 3a389633b68f..6155d97ec76c 100644 > --- a/include/linux/migrate.h > +++ b/include/linux/migrate.h > @@ -45,8 +45,6 @@ extern struct page *alloc_migration_target(struct page *page, unsigned long priv > 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_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, > @@ -66,9 +64,6 @@ static inline struct page *alloc_migration_target(struct page *page, > 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_prep_local(void) { return -ENOSYS; } > - > static inline void migrate_page_states(struct page *newpage, struct page *page) > { > } > diff --git a/mm/compaction.c b/mm/compaction.c > index e04f4476e68e..3be017ececc0 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -2319,7 +2319,8 @@ compact_zone(struct compact_control *cc, struct capture_control *capc) > 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; > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index ab51132547b8..fc024e97be37 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -1124,7 +1124,7 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, > int err = 0; > nodemask_t tmp; > > - migrate_prep(); > + lru_add_drain_all(); > > mmap_read_lock(mm); > > @@ -1323,7 +1323,7 @@ static long do_mbind(unsigned long start, unsigned long len, > > if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) { > > - migrate_prep(); > + lru_add_drain_all(); > } > { > NODEMASK_SCRATCH(scratch); > diff --git a/mm/migrate.c b/mm/migrate.c > index 62b81d5257aa..45f925e10f5a 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -57,28 +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. > - * Note that pages may be moved off the LRU after we have > - * drained them. Those pages will fail to migrate like other > - * pages that may be busy. > - */ > - lru_add_drain_all(); > -} > - > -/* 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; > @@ -1769,7 +1747,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > int start, i; > int err = 0, err1; > > - migrate_prep(); > + lru_add_drain_all(); > > for (i = start = 0; i < nr_pages; i++) { > const void __user *p; > diff --git a/mm/page_alloc.c b/mm/page_alloc.c > index 2e8348936df8..f05a8db741ca 100644 > --- a/mm/page_alloc.c > +++ b/mm/page_alloc.c > @@ -8467,7 +8467,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc, > .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, > }; > > - migrate_prep(); > + lru_add_drain_all(); > > while (pfn < end || !list_empty(&cc->migratepages)) { > if (fatal_signal_pending(current)) { > diff --git a/mm/swap.c b/mm/swap.c > index 31b844d4ed94..441d1ae1f285 100644 > --- a/mm/swap.c > +++ b/mm/swap.c > @@ -729,6 +729,11 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy) > } > > /* > + * lru_add_drain_all() usually needs to be called before we start compiling > + * a list of pages to be migrated using isolate_lru_page(). Note that pages > + * may be moved off the LRU after we have drained them. Those pages will > + * fail to migrate like other pages that may be busy. > + * > * Doesn't need any cpu hotplug locking because we do rely on per-cpu > * kworkers being shut down before our page_alloc_cpu_dead callback is > * executed on the offlined cpu. > Reviewed-by: David Hildenbrand <david@redhat.com>
diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 3a389633b68f..6155d97ec76c 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -45,8 +45,6 @@ extern struct page *alloc_migration_target(struct page *page, unsigned long priv 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_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, @@ -66,9 +64,6 @@ static inline struct page *alloc_migration_target(struct page *page, 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_prep_local(void) { return -ENOSYS; } - static inline void migrate_page_states(struct page *newpage, struct page *page) { } diff --git a/mm/compaction.c b/mm/compaction.c index e04f4476e68e..3be017ececc0 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -2319,7 +2319,8 @@ compact_zone(struct compact_control *cc, struct capture_control *capc) 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; diff --git a/mm/mempolicy.c b/mm/mempolicy.c index ab51132547b8..fc024e97be37 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1124,7 +1124,7 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from, int err = 0; nodemask_t tmp; - migrate_prep(); + lru_add_drain_all(); mmap_read_lock(mm); @@ -1323,7 +1323,7 @@ static long do_mbind(unsigned long start, unsigned long len, if (flags & (MPOL_MF_MOVE | MPOL_MF_MOVE_ALL)) { - migrate_prep(); + lru_add_drain_all(); } { NODEMASK_SCRATCH(scratch); diff --git a/mm/migrate.c b/mm/migrate.c index 62b81d5257aa..45f925e10f5a 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -57,28 +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. - * Note that pages may be moved off the LRU after we have - * drained them. Those pages will fail to migrate like other - * pages that may be busy. - */ - lru_add_drain_all(); -} - -/* 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; @@ -1769,7 +1747,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, int start, i; int err = 0, err1; - migrate_prep(); + lru_add_drain_all(); for (i = start = 0; i < nr_pages; i++) { const void __user *p; diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 2e8348936df8..f05a8db741ca 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -8467,7 +8467,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc, .gfp_mask = GFP_USER | __GFP_MOVABLE | __GFP_RETRY_MAYFAIL, }; - migrate_prep(); + lru_add_drain_all(); while (pfn < end || !list_empty(&cc->migratepages)) { if (fatal_signal_pending(current)) { diff --git a/mm/swap.c b/mm/swap.c index 31b844d4ed94..441d1ae1f285 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -729,6 +729,11 @@ static void lru_add_drain_per_cpu(struct work_struct *dummy) } /* + * lru_add_drain_all() usually needs to be called before we start compiling + * a list of pages to be migrated using isolate_lru_page(). Note that pages + * may be moved off the LRU after we have drained them. Those pages will + * fail to migrate like other pages that may be busy. + * * Doesn't need any cpu hotplug locking because we do rely on per-cpu * kworkers being shut down before our page_alloc_cpu_dead callback is * executed on the offlined cpu.
Currently, migrate_prep is merely a wrapper of lru_cache_add_all. There is not much to gain from having additional abstraction. Use lru_add_drain_all instead of migrate_prep, 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 keep old behavior. Signed-off-by: Minchan Kim <minchan@kernel.org> --- include/linux/migrate.h | 5 ----- mm/compaction.c | 3 ++- mm/mempolicy.c | 4 ++-- mm/migrate.c | 24 +----------------------- mm/page_alloc.c | 2 +- mm/swap.c | 5 +++++ 6 files changed, 11 insertions(+), 32 deletions(-)