| Message ID | 20240311193641.133981-1-zi.yan@sent.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/migrate: put dest folio on deferred split list if source was there. | expand |
On 11/03/2024 19:36, Zi Yan wrote: > From: Zi Yan <ziy@nvidia.com> > > Commit 616b8371539a6 ("mm: thp: enable thp migration in generic path") > did not check if a THP is on deferred split list before migration, thus, > the destination THP is never put on deferred split list even if the source > THP might be. The opportunity of reclaiming free pages in a partially > mapped THP during deferred list scanning is lost, but no other harmful > consequence is present[1]. Checking source folio deferred split list > status before page unmapped and add destination folio to the list if > source was after migration. > > [1]: https://lore.kernel.org/linux-mm/03CE3A00-917C-48CC-8E1C-6A98713C817C@nvidia.com/ > > Fixes: 616b8371539a ("mm: thp: enable thp migration in generic path") > Signed-off-by: Zi Yan <ziy@nvidia.com> > --- > mm/huge_memory.c | 22 ---------------------- > mm/internal.h | 23 +++++++++++++++++++++++ > mm/migrate.c | 26 +++++++++++++++++++++++++- > 3 files changed, 48 insertions(+), 23 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 9859aa4f7553..c6d4d0cdf4b3 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -766,28 +766,6 @@ pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) > return pmd; > } > > -#ifdef CONFIG_MEMCG > -static inline > -struct deferred_split *get_deferred_split_queue(struct folio *folio) > -{ > - struct mem_cgroup *memcg = folio_memcg(folio); > - struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); > - > - if (memcg) > - return &memcg->deferred_split_queue; > - else > - return &pgdat->deferred_split_queue; > -} > -#else > -static inline > -struct deferred_split *get_deferred_split_queue(struct folio *folio) > -{ > - struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); > - > - return &pgdat->deferred_split_queue; > -} > -#endif > - > void folio_prep_large_rmappable(struct folio *folio) > { > if (!folio || !folio_test_large(folio)) > diff --git a/mm/internal.h b/mm/internal.h > index d1c69119b24f..8fa36e84463a 100644 > --- a/mm/internal.h > +++ b/mm/internal.h > @@ -1107,6 +1107,29 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, > unsigned long addr, pmd_t *pmd, > unsigned int flags); > > +#ifdef CONFIG_MEMCG > +static inline > +struct deferred_split *get_deferred_split_queue(struct folio *folio) > +{ > + struct mem_cgroup *memcg = folio_memcg(folio); > + struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); > + > + if (memcg) > + return &memcg->deferred_split_queue; > + else > + return &pgdat->deferred_split_queue; > +} > +#else > +static inline > +struct deferred_split *get_deferred_split_queue(struct folio *folio) > +{ > + struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); > + > + return &pgdat->deferred_split_queue; > +} > +#endif > + > + > /* > * mm/mmap.c > */ > diff --git a/mm/migrate.c b/mm/migrate.c > index 73a052a382f1..84ba1c65d20d 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -20,6 +20,7 @@ > #include <linux/pagemap.h> > #include <linux/buffer_head.h> > #include <linux/mm_inline.h> > +#include <linux/mmzone.h> > #include <linux/nsproxy.h> > #include <linux/ksm.h> > #include <linux/rmap.h> > @@ -1037,7 +1038,10 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, > enum { > PAGE_WAS_MAPPED = BIT(0), > PAGE_WAS_MLOCKED = BIT(1), > - PAGE_OLD_STATES = PAGE_WAS_MAPPED | PAGE_WAS_MLOCKED, > + PAGE_WAS_ON_DEFERRED_LIST = BIT(2), > + PAGE_OLD_STATES = PAGE_WAS_MAPPED | > + PAGE_WAS_MLOCKED | > + PAGE_WAS_ON_DEFERRED_LIST, > }; > > static void __migrate_folio_record(struct folio *dst, > @@ -1168,6 +1172,17 @@ static int migrate_folio_unmap(new_folio_t get_new_folio, > folio_lock(src); > } > locked = true; > + if (folio_test_large_rmappable(src) && > + !list_empty(&src->_deferred_list)) { > + struct deferred_split *ds_queue = get_deferred_split_queue(src); > + > + spin_lock(&ds_queue->split_queue_lock); > + ds_queue->split_queue_len--; > + list_del_init(&src->_deferred_list); > + spin_unlock(&ds_queue->split_queue_lock); > + old_page_state |= PAGE_WAS_ON_DEFERRED_LIST; > + } > + > if (folio_test_mlocked(src)) > old_page_state |= PAGE_WAS_MLOCKED; > > @@ -1307,6 +1322,15 @@ static int migrate_folio_move(free_folio_t put_new_folio, unsigned long private, > if (old_page_state & PAGE_WAS_MAPPED) > remove_migration_ptes(src, dst, false); > > + if (old_page_state & PAGE_WAS_ON_DEFERRED_LIST) { > + struct deferred_split *ds_queue = get_deferred_split_queue(src); do you mean dst here? > + > + spin_lock(&ds_queue->split_queue_lock); > + ds_queue->split_queue_len++; > + list_add(&dst->_deferred_list, &ds_queue->split_queue); > + spin_unlock(&ds_queue->split_queue_lock); > + } > + > out_unlock_both: > folio_unlock(dst); > set_page_owner_migrate_reason(&dst->page, reason);
On 11 Mar 2024, at 15:53, Ryan Roberts wrote: > On 11/03/2024 19:36, Zi Yan wrote: >> From: Zi Yan <ziy@nvidia.com> >> >> Commit 616b8371539a6 ("mm: thp: enable thp migration in generic path") >> did not check if a THP is on deferred split list before migration, thus, >> the destination THP is never put on deferred split list even if the source >> THP might be. The opportunity of reclaiming free pages in a partially >> mapped THP during deferred list scanning is lost, but no other harmful >> consequence is present[1]. Checking source folio deferred split list >> status before page unmapped and add destination folio to the list if >> source was after migration. >> >> [1]: https://lore.kernel.org/linux-mm/03CE3A00-917C-48CC-8E1C-6A98713C817C@nvidia.com/ >> >> Fixes: 616b8371539a ("mm: thp: enable thp migration in generic path") >> Signed-off-by: Zi Yan <ziy@nvidia.com> >> --- >> mm/huge_memory.c | 22 ---------------------- >> mm/internal.h | 23 +++++++++++++++++++++++ >> mm/migrate.c | 26 +++++++++++++++++++++++++- >> 3 files changed, 48 insertions(+), 23 deletions(-) >> >> diff --git a/mm/huge_memory.c b/mm/huge_memory.c >> index 9859aa4f7553..c6d4d0cdf4b3 100644 >> --- a/mm/huge_memory.c >> +++ b/mm/huge_memory.c >> @@ -766,28 +766,6 @@ pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) >> return pmd; >> } >> >> -#ifdef CONFIG_MEMCG >> -static inline >> -struct deferred_split *get_deferred_split_queue(struct folio *folio) >> -{ >> - struct mem_cgroup *memcg = folio_memcg(folio); >> - struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); >> - >> - if (memcg) >> - return &memcg->deferred_split_queue; >> - else >> - return &pgdat->deferred_split_queue; >> -} >> -#else >> -static inline >> -struct deferred_split *get_deferred_split_queue(struct folio *folio) >> -{ >> - struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); >> - >> - return &pgdat->deferred_split_queue; >> -} >> -#endif >> - >> void folio_prep_large_rmappable(struct folio *folio) >> { >> if (!folio || !folio_test_large(folio)) >> diff --git a/mm/internal.h b/mm/internal.h >> index d1c69119b24f..8fa36e84463a 100644 >> --- a/mm/internal.h >> +++ b/mm/internal.h >> @@ -1107,6 +1107,29 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, >> unsigned long addr, pmd_t *pmd, >> unsigned int flags); >> >> +#ifdef CONFIG_MEMCG >> +static inline >> +struct deferred_split *get_deferred_split_queue(struct folio *folio) >> +{ >> + struct mem_cgroup *memcg = folio_memcg(folio); >> + struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); >> + >> + if (memcg) >> + return &memcg->deferred_split_queue; >> + else >> + return &pgdat->deferred_split_queue; >> +} >> +#else >> +static inline >> +struct deferred_split *get_deferred_split_queue(struct folio *folio) >> +{ >> + struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); >> + >> + return &pgdat->deferred_split_queue; >> +} >> +#endif >> + >> + >> /* >> * mm/mmap.c >> */ >> diff --git a/mm/migrate.c b/mm/migrate.c >> index 73a052a382f1..84ba1c65d20d 100644 >> --- a/mm/migrate.c >> +++ b/mm/migrate.c >> @@ -20,6 +20,7 @@ >> #include <linux/pagemap.h> >> #include <linux/buffer_head.h> >> #include <linux/mm_inline.h> >> +#include <linux/mmzone.h> >> #include <linux/nsproxy.h> >> #include <linux/ksm.h> >> #include <linux/rmap.h> >> @@ -1037,7 +1038,10 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, >> enum { >> PAGE_WAS_MAPPED = BIT(0), >> PAGE_WAS_MLOCKED = BIT(1), >> - PAGE_OLD_STATES = PAGE_WAS_MAPPED | PAGE_WAS_MLOCKED, >> + PAGE_WAS_ON_DEFERRED_LIST = BIT(2), >> + PAGE_OLD_STATES = PAGE_WAS_MAPPED | >> + PAGE_WAS_MLOCKED | >> + PAGE_WAS_ON_DEFERRED_LIST, >> }; >> >> static void __migrate_folio_record(struct folio *dst, >> @@ -1168,6 +1172,17 @@ static int migrate_folio_unmap(new_folio_t get_new_folio, >> folio_lock(src); >> } >> locked = true; >> + if (folio_test_large_rmappable(src) && >> + !list_empty(&src->_deferred_list)) { >> + struct deferred_split *ds_queue = get_deferred_split_queue(src); >> + >> + spin_lock(&ds_queue->split_queue_lock); >> + ds_queue->split_queue_len--; >> + list_del_init(&src->_deferred_list); >> + spin_unlock(&ds_queue->split_queue_lock); >> + old_page_state |= PAGE_WAS_ON_DEFERRED_LIST; >> + } >> + >> if (folio_test_mlocked(src)) >> old_page_state |= PAGE_WAS_MLOCKED; >> >> @@ -1307,6 +1322,15 @@ static int migrate_folio_move(free_folio_t put_new_folio, unsigned long private, >> if (old_page_state & PAGE_WAS_MAPPED) >> remove_migration_ptes(src, dst, false); >> >> + if (old_page_state & PAGE_WAS_ON_DEFERRED_LIST) { >> + struct deferred_split *ds_queue = get_deferred_split_queue(src); > > do you mean dst here? Right. I forgot the case of migrating from one node to another and thought either src or dst works. Thanks. > >> + >> + spin_lock(&ds_queue->split_queue_lock); >> + ds_queue->split_queue_len++; >> + list_add(&dst->_deferred_list, &ds_queue->split_queue); >> + spin_unlock(&ds_queue->split_queue_lock); >> + } >> + >> out_unlock_both: >> folio_unlock(dst); >> set_page_owner_migrate_reason(&dst->page, reason); -- Best Regards, Yan, Zi
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 9859aa4f7553..c6d4d0cdf4b3 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -766,28 +766,6 @@ pmd_t maybe_pmd_mkwrite(pmd_t pmd, struct vm_area_struct *vma) return pmd; } -#ifdef CONFIG_MEMCG -static inline -struct deferred_split *get_deferred_split_queue(struct folio *folio) -{ - struct mem_cgroup *memcg = folio_memcg(folio); - struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); - - if (memcg) - return &memcg->deferred_split_queue; - else - return &pgdat->deferred_split_queue; -} -#else -static inline -struct deferred_split *get_deferred_split_queue(struct folio *folio) -{ - struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); - - return &pgdat->deferred_split_queue; -} -#endif - void folio_prep_large_rmappable(struct folio *folio) { if (!folio || !folio_test_large(folio)) diff --git a/mm/internal.h b/mm/internal.h index d1c69119b24f..8fa36e84463a 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -1107,6 +1107,29 @@ struct page *follow_trans_huge_pmd(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned int flags); +#ifdef CONFIG_MEMCG +static inline +struct deferred_split *get_deferred_split_queue(struct folio *folio) +{ + struct mem_cgroup *memcg = folio_memcg(folio); + struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); + + if (memcg) + return &memcg->deferred_split_queue; + else + return &pgdat->deferred_split_queue; +} +#else +static inline +struct deferred_split *get_deferred_split_queue(struct folio *folio) +{ + struct pglist_data *pgdat = NODE_DATA(folio_nid(folio)); + + return &pgdat->deferred_split_queue; +} +#endif + + /* * mm/mmap.c */ diff --git a/mm/migrate.c b/mm/migrate.c index 73a052a382f1..84ba1c65d20d 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -20,6 +20,7 @@ #include <linux/pagemap.h> #include <linux/buffer_head.h> #include <linux/mm_inline.h> +#include <linux/mmzone.h> #include <linux/nsproxy.h> #include <linux/ksm.h> #include <linux/rmap.h> @@ -1037,7 +1038,10 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, enum { PAGE_WAS_MAPPED = BIT(0), PAGE_WAS_MLOCKED = BIT(1), - PAGE_OLD_STATES = PAGE_WAS_MAPPED | PAGE_WAS_MLOCKED, + PAGE_WAS_ON_DEFERRED_LIST = BIT(2), + PAGE_OLD_STATES = PAGE_WAS_MAPPED | + PAGE_WAS_MLOCKED | + PAGE_WAS_ON_DEFERRED_LIST, }; static void __migrate_folio_record(struct folio *dst, @@ -1168,6 +1172,17 @@ static int migrate_folio_unmap(new_folio_t get_new_folio, folio_lock(src); } locked = true; + if (folio_test_large_rmappable(src) && + !list_empty(&src->_deferred_list)) { + struct deferred_split *ds_queue = get_deferred_split_queue(src); + + spin_lock(&ds_queue->split_queue_lock); + ds_queue->split_queue_len--; + list_del_init(&src->_deferred_list); + spin_unlock(&ds_queue->split_queue_lock); + old_page_state |= PAGE_WAS_ON_DEFERRED_LIST; + } + if (folio_test_mlocked(src)) old_page_state |= PAGE_WAS_MLOCKED; @@ -1307,6 +1322,15 @@ static int migrate_folio_move(free_folio_t put_new_folio, unsigned long private, if (old_page_state & PAGE_WAS_MAPPED) remove_migration_ptes(src, dst, false); + if (old_page_state & PAGE_WAS_ON_DEFERRED_LIST) { + struct deferred_split *ds_queue = get_deferred_split_queue(src); + + spin_lock(&ds_queue->split_queue_lock); + ds_queue->split_queue_len++; + list_add(&dst->_deferred_list, &ds_queue->split_queue); + spin_unlock(&ds_queue->split_queue_lock); + } + out_unlock_both: folio_unlock(dst); set_page_owner_migrate_reason(&dst->page, reason);