From fcd48540d188876c917a377d81cd24c100332a62 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Fri, 16 Dec 2022 10:50:55 -0500 Subject: mm/hugetlb: move swap entry handling into vma lock when faulted In hugetlb_fault(), there used to have a special path to handle swap entry at the entrance using huge_pte_offset(). That's unsafe because huge_pte_offset() for a pmd sharable range can access freed pgtables if without any lock to protect the pgtable from being freed after pmd unshare. Here the simplest solution to make it safe is to move the swap handling to be after the vma lock being held. We may need to take the fault mutex on either migration or hwpoison entries now (also the vma lock, but that's really needed), however neither of them is hot path. Note that the vma lock cannot be released in hugetlb_fault() when the migration entry is detected, because in migration_entry_wait_huge() the pgtable page will be used again (by taking the pgtable lock), so that also need to be protected by the vma lock. Modify migration_entry_wait_huge() so that it must be called with vma read lock held, and properly release the lock in __migration_entry_wait_huge(). Link: https://lkml.kernel.org/r/20221216155100.2043537-5-peterx@redhat.com Signed-off-by: Peter Xu Reviewed-by: Mike Kravetz Reviewed-by: John Hubbard Cc: Andrea Arcangeli Cc: David Hildenbrand Cc: James Houghton Cc: Jann Horn Cc: Miaohe Lin Cc: Muchun Song Cc: Nadav Amit Cc: Rik van Riel Signed-off-by: Andrew Morton --- mm/migrate.c | 25 +++++++++++++++++++++---- 1 file changed, 21 insertions(+), 4 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index a4d3fc65085f..98de7ce2b576 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -329,24 +329,41 @@ void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, } #ifdef CONFIG_HUGETLB_PAGE -void __migration_entry_wait_huge(pte_t *ptep, spinlock_t *ptl) +/* + * The vma read lock must be held upon entry. Holding that lock prevents either + * the pte or the ptl from being freed. + * + * This function will release the vma lock before returning. + */ +void __migration_entry_wait_huge(struct vm_area_struct *vma, + pte_t *ptep, spinlock_t *ptl) { pte_t pte; + hugetlb_vma_assert_locked(vma); spin_lock(ptl); pte = huge_ptep_get(ptep); - if (unlikely(!is_hugetlb_entry_migration(pte))) + if (unlikely(!is_hugetlb_entry_migration(pte))) { spin_unlock(ptl); - else + hugetlb_vma_unlock_read(vma); + } else { + /* + * If migration entry existed, safe to release vma lock + * here because the pgtable page won't be freed without the + * pgtable lock released. See comment right above pgtable + * lock release in migration_entry_wait_on_locked(). + */ + hugetlb_vma_unlock_read(vma); migration_entry_wait_on_locked(pte_to_swp_entry(pte), NULL, ptl); + } } void migration_entry_wait_huge(struct vm_area_struct *vma, pte_t *pte) { spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), vma->vm_mm, pte); - __migration_entry_wait_huge(pte, ptl); + __migration_entry_wait_huge(vma, pte, ptl); } #endif -- cgit v1.2.3 From 96f97c438f61ddba94117dcd1a1eb0aaafa22309 Mon Sep 17 00:00:00 2001 From: Lorenzo Stoakes Date: Thu, 12 Jan 2023 12:39:31 +0000 Subject: mm: mlock: update the interface to use folios Update the mlock interface to accept folios rather than pages, bringing the interface in line with the internal implementation. munlock_vma_page() still requires a page_folio() conversion, however this is consistent with the existent mlock_vma_page() implementation and a product of rmap still dealing in pages rather than folios. Link: https://lkml.kernel.org/r/cba12777c5544305014bc0cbec56bb4cc71477d8.1673526881.git.lstoakes@gmail.com Signed-off-by: Lorenzo Stoakes Acked-by: Vlastimil Babka Cc: Christian Brauner Cc: Geert Uytterhoeven Cc: Hugh Dickins Cc: Joel Fernandes (Google) Cc: Jonathan Corbet Cc: Liam R. Howlett Cc: Matthew Wilcox Cc: Mike Rapoport (IBM) Cc: William Kucharski Signed-off-by: Andrew Morton --- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 98de7ce2b576..206fcdbe67f3 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -265,7 +265,7 @@ static bool remove_migration_pte(struct folio *folio, set_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte); } if (vma->vm_flags & VM_LOCKED) - mlock_page_drain_local(); + mlock_drain_local(); trace_remove_migration_pte(pvmw.address, pte_val(pte), compound_order(new)); -- cgit v1.2.3 From 6aa3a920125e9f58891e2b5dc2efd4d0c1ff05a6 Mon Sep 17 00:00:00 2001 From: Sidhartha Kumar Date: Fri, 13 Jan 2023 16:30:50 -0600 Subject: mm/hugetlb: convert isolate_hugetlb to folios Patch series "continue hugetlb folio conversion", v3. This series continues the conversion of core hugetlb functions to use folios. This series converts many helper funtions in the hugetlb fault path. This is in preparation for another series to convert the hugetlb fault code paths to operate on folios. This patch (of 8): Convert isolate_hugetlb() to take in a folio and convert its callers to pass a folio. Use page_folio() to convert the callers to use a folio is safe as isolate_hugetlb() operates on a head page. Link: https://lkml.kernel.org/r/20230113223057.173292-1-sidhartha.kumar@oracle.com Link: https://lkml.kernel.org/r/20230113223057.173292-2-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Reviewed-by: Mike Kravetz Cc: John Hubbard Cc: Matthew Wilcox Cc: Mike Kravetz Cc: Muchun Song Signed-off-by: Andrew Morton --- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 206fcdbe67f3..f6464bce7678 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1773,7 +1773,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, if (PageHuge(page)) { if (PageHead(page)) { - err = isolate_hugetlb(page, pagelist); + err = isolate_hugetlb(page_folio(page), pagelist); if (!err) err = 1; } -- cgit v1.2.3 From e37d3e838d9078538f920957d1e89682b6764977 Mon Sep 17 00:00:00 2001 From: Sidhartha Kumar Date: Fri, 13 Jan 2023 16:30:55 -0600 Subject: mm/hugetlb: convert alloc_migrate_huge_page to folios Change alloc_huge_page_nodemask() to alloc_hugetlb_folio_nodemask() and alloc_migrate_huge_page() to alloc_migrate_hugetlb_folio(). Both functions now return a folio rather than a page. Link: https://lkml.kernel.org/r/20230113223057.173292-7-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Reviewed-by: Mike Kravetz Cc: John Hubbard Cc: Matthew Wilcox Cc: Muchun Song Signed-off-by: Andrew Morton --- mm/migrate.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index f6464bce7678..811e76c6fac1 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1663,6 +1663,7 @@ struct page *alloc_migration_target(struct page *page, unsigned long private) struct migration_target_control *mtc; gfp_t gfp_mask; unsigned int order = 0; + struct folio *hugetlb_folio = NULL; struct folio *new_folio = NULL; int nid; int zidx; @@ -1677,7 +1678,9 @@ struct page *alloc_migration_target(struct page *page, unsigned long private) struct hstate *h = folio_hstate(folio); gfp_mask = htlb_modify_alloc_mask(h, gfp_mask); - return alloc_huge_page_nodemask(h, nid, mtc->nmask, gfp_mask); + hugetlb_folio = alloc_hugetlb_folio_nodemask(h, nid, + mtc->nmask, gfp_mask); + return &hugetlb_folio->page; } if (folio_test_large(folio)) { -- cgit v1.2.3 From ea8e72f4116a995c2aba3fb738ac372c4115375a Mon Sep 17 00:00:00 2001 From: Sidhartha Kumar Date: Wed, 25 Jan 2023 09:05:32 -0800 Subject: mm/hugetlb: convert putback_active_hugepage to take in a folio Convert putback_active_hugepage() to folio_putback_active_hugetlb(), this removes one user of the Huge Page macros which take in a page. The callers in migrate.c are also cleaned up by being able to directly use the src and dst folio variables. Link: https://lkml.kernel.org/r/20230125170537.96973-4-sidhartha.kumar@oracle.com Signed-off-by: Sidhartha Kumar Reviewed-by: Mike Kravetz Cc: Gerald Schaefer Cc: John Hubbard Cc: Matthew Wilcox Cc: Muchun Song Signed-off-by: Andrew Morton --- mm/migrate.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 811e76c6fac1..c09872cf41b7 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -151,7 +151,7 @@ void putback_movable_pages(struct list_head *l) list_for_each_entry_safe(page, page2, l, lru) { if (unlikely(PageHuge(page))) { - putback_active_hugepage(page); + folio_putback_active_hugetlb(page_folio(page)); continue; } list_del(&page->lru); @@ -1298,7 +1298,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, if (folio_ref_count(src) == 1) { /* page was freed from under us. So we are done. */ - putback_active_hugepage(hpage); + folio_putback_active_hugetlb(src); return MIGRATEPAGE_SUCCESS; } @@ -1383,7 +1383,7 @@ out_unlock: folio_unlock(src); out: if (rc == MIGRATEPAGE_SUCCESS) - putback_active_hugepage(hpage); + folio_putback_active_hugetlb(src); else if (rc != -EAGAIN) list_move_tail(&src->lru, ret); @@ -1395,7 +1395,7 @@ out: if (put_new_page) put_new_page(new_hpage, private); else - putback_active_hugepage(new_hpage); + folio_putback_active_hugetlb(dst); return rc; } -- cgit v1.2.3 From da707a6d184a8a6ef0b756c3ba49888fec223793 Mon Sep 17 00:00:00 2001 From: "Vishal Moola (Oracle)" Date: Mon, 30 Jan 2023 13:43:50 -0800 Subject: mm/migrate: add folio_movable_ops() folio_movable_ops() does the same as page_movable_ops() except uses folios instead of pages. This function will help make folio conversions in migrate.c more readable. Link: https://lkml.kernel.org/r/20230130214352.40538-3-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/migrate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index c09872cf41b7..d2b1167329b9 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -990,7 +990,7 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, goto out; } - mops = page_movable_ops(&src->page); + mops = folio_movable_ops(src); rc = mops->migrate_page(&dst->page, &src->page, mode); WARN_ON_ONCE(rc == MIGRATEPAGE_SUCCESS && !folio_test_isolated(src)); -- cgit v1.2.3 From 19979497c02a365ed9d8276b5f4cc36557a13ced Mon Sep 17 00:00:00 2001 From: "Vishal Moola (Oracle)" Date: Mon, 30 Jan 2023 13:43:51 -0800 Subject: mm/migrate: convert isolate_movable_page() to use folios Removes 6 calls to compound_head() and prepares the function to take in a folio instead of page argument. Link: https://lkml.kernel.org/r/20230130214352.40538-4-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/migrate.c | 39 ++++++++++++++++++++------------------- 1 file changed, 20 insertions(+), 19 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index d2b1167329b9..3cdb76e44ef5 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -60,6 +60,7 @@ int isolate_movable_page(struct page *page, isolate_mode_t mode) { + struct folio *folio = folio_get_nontail_page(page); const struct movable_operations *mops; /* @@ -71,11 +72,11 @@ int isolate_movable_page(struct page *page, isolate_mode_t mode) * the put_page() at the end of this block will take care of * release this page, thus avoiding a nasty leakage. */ - if (unlikely(!get_page_unless_zero(page))) + if (!folio) goto out; - if (unlikely(PageSlab(page))) - goto out_putpage; + if (unlikely(folio_test_slab(folio))) + goto out_putfolio; /* Pairs with smp_wmb() in slab freeing, e.g. SLUB's __free_slab() */ smp_rmb(); /* @@ -83,12 +84,12 @@ int isolate_movable_page(struct page *page, isolate_mode_t mode) * we use non-atomic bitops on newly allocated page flags so * unconditionally grabbing the lock ruins page's owner side. */ - if (unlikely(!__PageMovable(page))) - goto out_putpage; + if (unlikely(!__folio_test_movable(folio))) + goto out_putfolio; /* Pairs with smp_wmb() in slab allocation, e.g. SLUB's alloc_slab_page() */ smp_rmb(); - if (unlikely(PageSlab(page))) - goto out_putpage; + if (unlikely(folio_test_slab(folio))) + goto out_putfolio; /* * As movable pages are not isolated from LRU lists, concurrent @@ -101,29 +102,29 @@ int isolate_movable_page(struct page *page, isolate_mode_t mode) * lets be sure we have the page lock * before proceeding with the movable page isolation steps. */ - if (unlikely(!trylock_page(page))) - goto out_putpage; + if (unlikely(!folio_trylock(folio))) + goto out_putfolio; - if (!PageMovable(page) || PageIsolated(page)) + if (!folio_test_movable(folio) || folio_test_isolated(folio)) goto out_no_isolated; - mops = page_movable_ops(page); - VM_BUG_ON_PAGE(!mops, page); + mops = folio_movable_ops(folio); + VM_BUG_ON_FOLIO(!mops, folio); - if (!mops->isolate_page(page, mode)) + if (!mops->isolate_page(&folio->page, mode)) goto out_no_isolated; /* Driver shouldn't use PG_isolated bit of page->flags */ - WARN_ON_ONCE(PageIsolated(page)); - SetPageIsolated(page); - unlock_page(page); + WARN_ON_ONCE(folio_test_isolated(folio)); + folio_set_isolated(folio); + folio_unlock(folio); return 0; out_no_isolated: - unlock_page(page); -out_putpage: - put_page(page); + folio_unlock(folio); +out_putfolio: + folio_put(folio); out: return -EBUSY; } -- cgit v1.2.3 From 280d724ac20f9cc463d4ab8e2269f598476b070f Mon Sep 17 00:00:00 2001 From: "Vishal Moola (Oracle)" Date: Mon, 30 Jan 2023 13:43:52 -0800 Subject: mm/migrate: convert putback_movable_pages() to use folios Removes 6 calls to compound_head(), and replaces putback_movable_page() with putback_movable_folio() as well. Link: https://lkml.kernel.org/r/20230130214352.40538-5-vishal.moola@gmail.com Signed-off-by: Vishal Moola (Oracle) Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- mm/migrate.c | 46 +++++++++++++++++++++++----------------------- 1 file changed, 23 insertions(+), 23 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 3cdb76e44ef5..5b40b9040ba6 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -129,12 +129,12 @@ out: return -EBUSY; } -static void putback_movable_page(struct page *page) +static void putback_movable_folio(struct folio *folio) { - const struct movable_operations *mops = page_movable_ops(page); + const struct movable_operations *mops = folio_movable_ops(folio); - mops->putback_page(page); - ClearPageIsolated(page); + mops->putback_page(&folio->page); + folio_clear_isolated(folio); } /* @@ -147,33 +147,33 @@ static void putback_movable_page(struct page *page) */ void putback_movable_pages(struct list_head *l) { - struct page *page; - struct page *page2; + struct folio *folio; + struct folio *folio2; - list_for_each_entry_safe(page, page2, l, lru) { - if (unlikely(PageHuge(page))) { - folio_putback_active_hugetlb(page_folio(page)); + list_for_each_entry_safe(folio, folio2, l, lru) { + if (unlikely(folio_test_hugetlb(folio))) { + folio_putback_active_hugetlb(folio); continue; } - list_del(&page->lru); + list_del(&folio->lru); /* - * We isolated non-lru movable page so here we can use - * __PageMovable because LRU page's mapping cannot have + * We isolated non-lru movable folio so here we can use + * __PageMovable because LRU folio's mapping cannot have * PAGE_MAPPING_MOVABLE. */ - if (unlikely(__PageMovable(page))) { - VM_BUG_ON_PAGE(!PageIsolated(page), page); - lock_page(page); - if (PageMovable(page)) - putback_movable_page(page); + if (unlikely(__folio_test_movable(folio))) { + VM_BUG_ON_FOLIO(!folio_test_isolated(folio), folio); + folio_lock(folio); + if (folio_test_movable(folio)) + putback_movable_folio(folio); else - ClearPageIsolated(page); - unlock_page(page); - put_page(page); + folio_clear_isolated(folio); + folio_unlock(folio); + folio_put(folio); } else { - mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + - page_is_file_lru(page), -thp_nr_pages(page)); - putback_lru_page(page); + node_stat_mod_folio(folio, NR_ISOLATED_ANON + + folio_is_file_lru(folio), -folio_nr_pages(folio)); + folio_putback_lru(folio); } } } -- cgit v1.2.3 From 5b855937096aea7f81e73ad6d40d433c9dd49577 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:36 +0800 Subject: migrate_pages: organize stats with struct migrate_pages_stats Patch series "migrate_pages(): batch TLB flushing", v5. Now, migrate_pages() migrates folios one by one, like the fake code as follows, for each folio unmap flush TLB copy restore map If multiple folios are passed to migrate_pages(), there are opportunities to batch the TLB flushing and copying. That is, we can change the code to something as follows, for each folio unmap for each folio flush TLB for each folio copy for each folio restore map The total number of TLB flushing IPI can be reduced considerably. And we may use some hardware accelerator such as DSA to accelerate the folio copying. So in this patch, we refactor the migrate_pages() implementation and implement the TLB flushing batching. Base on this, hardware accelerated folio copying can be implemented. If too many folios are passed to migrate_pages(), in the naive batched implementation, we may unmap too many folios at the same time. The possibility for a task to wait for the migrated folios to be mapped again increases. So the latency may be hurt. To deal with this issue, the max number of folios be unmapped in batch is restricted to no more than HPAGE_PMD_NR in the unit of page. That is, the influence is at the same level of THP migration. We use the following test to measure the performance impact of the patchset, On a 2-socket Intel server, - Run pmbench memory accessing benchmark - Run `migratepages` to migrate pages of pmbench between node 0 and node 1 back and forth. With the patch, the TLB flushing IPI reduces 99.1% during the test and the number of pages migrated successfully per second increases 291.7%. Xin Hao helped to test the patchset on an ARM64 server with 128 cores, 2 NUMA nodes. Test results show that the page migration performance increases up to 78%. This patch (of 9): Define struct migrate_pages_stats to organize the various statistics in migrate_pages(). This makes it easier to collect and consume the statistics in multiple functions. This will be needed in the following patches in the series. Link: https://lkml.kernel.org/r/20230213123444.155149-1-ying.huang@intel.com Link: https://lkml.kernel.org/r/20230213123444.155149-2-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Alistair Popple Reviewed-by: Zi Yan Reviewed-by: Baolin Wang Reviewed-by: Xin Hao Cc: Yang Shi Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 60 ++++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 34 insertions(+), 26 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 5b40b9040ba6..1a9cfcf857d2 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1414,6 +1414,16 @@ static inline int try_split_folio(struct folio *folio, struct list_head *split_f return rc; } +struct migrate_pages_stats { + int nr_succeeded; /* Normal and large folios migrated successfully, in + units of base pages */ + int nr_failed_pages; /* Normal and large folios failed to be migrated, in + units of base pages. Untried folios aren't counted */ + int nr_thp_succeeded; /* THP migrated successfully */ + int nr_thp_failed; /* THP failed to be migrated */ + int nr_thp_split; /* THP split before migrating */ +}; + /* * migrate_pages - migrate the folios specified in a list, to the free folios * supplied as the target for the page migration @@ -1448,13 +1458,8 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, int large_retry = 1; int thp_retry = 1; int nr_failed = 0; - int nr_failed_pages = 0; int nr_retry_pages = 0; - int nr_succeeded = 0; - int nr_thp_succeeded = 0; int nr_large_failed = 0; - int nr_thp_failed = 0; - int nr_thp_split = 0; int pass = 0; bool is_large = false; bool is_thp = false; @@ -1464,9 +1469,11 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, LIST_HEAD(split_folios); bool nosplit = (reason == MR_NUMA_MISPLACED); bool no_split_folio_counting = false; + struct migrate_pages_stats stats; trace_mm_migrate_pages_start(mode, reason); + memset(&stats, 0, sizeof(stats)); split_folio_migration: for (pass = 0; pass < 10 && (retry || large_retry); pass++) { retry = 0; @@ -1520,9 +1527,9 @@ split_folio_migration: /* Large folio migration is unsupported */ if (is_large) { nr_large_failed++; - nr_thp_failed += is_thp; + stats.nr_thp_failed += is_thp; if (!try_split_folio(folio, &split_folios)) { - nr_thp_split += is_thp; + stats.nr_thp_split += is_thp; break; } /* Hugetlb migration is unsupported */ @@ -1530,7 +1537,7 @@ split_folio_migration: nr_failed++; } - nr_failed_pages += nr_pages; + stats.nr_failed_pages += nr_pages; list_move_tail(&folio->lru, &ret_folios); break; case -ENOMEM: @@ -1540,13 +1547,13 @@ split_folio_migration: */ if (is_large) { nr_large_failed++; - nr_thp_failed += is_thp; + stats.nr_thp_failed += is_thp; /* Large folio NUMA faulting doesn't split to retry. */ if (!nosplit) { int ret = try_split_folio(folio, &split_folios); if (!ret) { - nr_thp_split += is_thp; + stats.nr_thp_split += is_thp; break; } else if (reason == MR_LONGTERM_PIN && ret == -EAGAIN) { @@ -1564,7 +1571,7 @@ split_folio_migration: nr_failed++; } - nr_failed_pages += nr_pages + nr_retry_pages; + stats.nr_failed_pages += nr_pages + nr_retry_pages; /* * There might be some split folios of fail-to-migrate large * folios left in split_folios list. Move them back to migration @@ -1574,7 +1581,7 @@ split_folio_migration: list_splice_init(&split_folios, from); /* nr_failed isn't updated for not used */ nr_large_failed += large_retry; - nr_thp_failed += thp_retry; + stats.nr_thp_failed += thp_retry; goto out; case -EAGAIN: if (is_large) { @@ -1586,8 +1593,8 @@ split_folio_migration: nr_retry_pages += nr_pages; break; case MIGRATEPAGE_SUCCESS: - nr_succeeded += nr_pages; - nr_thp_succeeded += is_thp; + stats.nr_succeeded += nr_pages; + stats.nr_thp_succeeded += is_thp; break; default: /* @@ -1598,20 +1605,20 @@ split_folio_migration: */ if (is_large) { nr_large_failed++; - nr_thp_failed += is_thp; + stats.nr_thp_failed += is_thp; } else if (!no_split_folio_counting) { nr_failed++; } - nr_failed_pages += nr_pages; + stats.nr_failed_pages += nr_pages; break; } } } nr_failed += retry; nr_large_failed += large_retry; - nr_thp_failed += thp_retry; - nr_failed_pages += nr_retry_pages; + stats.nr_thp_failed += thp_retry; + stats.nr_failed_pages += nr_retry_pages; /* * Try to migrate split folios of fail-to-migrate large folios, no * nr_failed counting in this round, since all split folios of a @@ -1644,16 +1651,17 @@ out: if (list_empty(from)) rc = 0; - count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded); - count_vm_events(PGMIGRATE_FAIL, nr_failed_pages); - count_vm_events(THP_MIGRATION_SUCCESS, nr_thp_succeeded); - count_vm_events(THP_MIGRATION_FAIL, nr_thp_failed); - count_vm_events(THP_MIGRATION_SPLIT, nr_thp_split); - trace_mm_migrate_pages(nr_succeeded, nr_failed_pages, nr_thp_succeeded, - nr_thp_failed, nr_thp_split, mode, reason); + count_vm_events(PGMIGRATE_SUCCESS, stats.nr_succeeded); + count_vm_events(PGMIGRATE_FAIL, stats.nr_failed_pages); + count_vm_events(THP_MIGRATION_SUCCESS, stats.nr_thp_succeeded); + count_vm_events(THP_MIGRATION_FAIL, stats.nr_thp_failed); + count_vm_events(THP_MIGRATION_SPLIT, stats.nr_thp_split); + trace_mm_migrate_pages(stats.nr_succeeded, stats.nr_failed_pages, + stats.nr_thp_succeeded, stats.nr_thp_failed, + stats.nr_thp_split, mode, reason); if (ret_succeeded) - *ret_succeeded = nr_succeeded; + *ret_succeeded = stats.nr_succeeded; return rc; } -- cgit v1.2.3 From e5bfff8b10e496378da4b7863479dd6fb907d4ea Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:37 +0800 Subject: migrate_pages: separate hugetlb folios migration This is a preparation patch to batch the folio unmapping and moving for the non-hugetlb folios. Based on that we can batch the TLB shootdown during the folio migration and make it possible to use some hardware accelerator for the folio copying. In this patch the hugetlb folios and non-hugetlb folios migration is separated in migrate_pages() to make it easy to change the non-hugetlb folios migration implementation. Link: https://lkml.kernel.org/r/20230213123444.155149-3-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Baolin Wang Reviewed-by: Xin Hao Cc: Zi Yan Cc: Yang Shi Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 141 +++++++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 119 insertions(+), 22 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 1a9cfcf857d2..586a32bdaa71 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1414,6 +1414,8 @@ static inline int try_split_folio(struct folio *folio, struct list_head *split_f return rc; } +#define NR_MAX_MIGRATE_PAGES_RETRY 10 + struct migrate_pages_stats { int nr_succeeded; /* Normal and large folios migrated successfully, in units of base pages */ @@ -1424,6 +1426,95 @@ struct migrate_pages_stats { int nr_thp_split; /* THP split before migrating */ }; +/* + * Returns the number of hugetlb folios that were not migrated, or an error code + * after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no hugetlb folios are movable + * any more because the list has become empty or no retryable hugetlb folios + * exist any more. It is caller's responsibility to call putback_movable_pages() + * only if ret != 0. + */ +static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, + free_page_t put_new_page, unsigned long private, + enum migrate_mode mode, int reason, + struct migrate_pages_stats *stats, + struct list_head *ret_folios) +{ + int retry = 1; + int nr_failed = 0; + int nr_retry_pages = 0; + int pass = 0; + struct folio *folio, *folio2; + int rc, nr_pages; + + for (pass = 0; pass < NR_MAX_MIGRATE_PAGES_RETRY && retry; pass++) { + retry = 0; + nr_retry_pages = 0; + + list_for_each_entry_safe(folio, folio2, from, lru) { + if (!folio_test_hugetlb(folio)) + continue; + + nr_pages = folio_nr_pages(folio); + + cond_resched(); + + rc = unmap_and_move_huge_page(get_new_page, + put_new_page, private, + &folio->page, pass > 2, mode, + reason, ret_folios); + /* + * The rules are: + * Success: hugetlb folio will be put back + * -EAGAIN: stay on the from list + * -ENOMEM: stay on the from list + * -ENOSYS: stay on the from list + * Other errno: put on ret_folios list + */ + switch(rc) { + case -ENOSYS: + /* Hugetlb migration is unsupported */ + nr_failed++; + stats->nr_failed_pages += nr_pages; + list_move_tail(&folio->lru, ret_folios); + break; + case -ENOMEM: + /* + * When memory is low, don't bother to try to migrate + * other folios, just exit. + */ + stats->nr_failed_pages += nr_pages + nr_retry_pages; + return -ENOMEM; + case -EAGAIN: + retry++; + nr_retry_pages += nr_pages; + break; + case MIGRATEPAGE_SUCCESS: + stats->nr_succeeded += nr_pages; + break; + default: + /* + * Permanent failure (-EBUSY, etc.): + * unlike -EAGAIN case, the failed folio is + * removed from migration folio list and not + * retried in the next outer loop. + */ + nr_failed++; + stats->nr_failed_pages += nr_pages; + break; + } + } + } + /* + * nr_failed is number of hugetlb folios failed to be migrated. After + * NR_MAX_MIGRATE_PAGES_RETRY attempts, give up and count retried hugetlb + * folios as failed. + */ + nr_failed += retry; + stats->nr_failed_pages += nr_retry_pages; + + return nr_failed; +} + /* * migrate_pages - migrate the folios specified in a list, to the free folios * supplied as the target for the page migration @@ -1440,10 +1531,10 @@ struct migrate_pages_stats { * @ret_succeeded: Set to the number of folios migrated successfully if * the caller passes a non-NULL pointer. * - * The function returns after 10 attempts or if no folios are movable any more - * because the list has become empty or no retryable folios exist any more. - * It is caller's responsibility to call putback_movable_pages() to return folios - * to the LRU or free list only if ret != 0. + * The function returns after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no folios + * are movable any more because the list has become empty or no retryable folios + * exist any more. It is caller's responsibility to call putback_movable_pages() + * only if ret != 0. * * Returns the number of {normal folio, large folio, hugetlb} that were not * migrated, or an error code. The number of large folio splits will be @@ -1457,7 +1548,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, int retry = 1; int large_retry = 1; int thp_retry = 1; - int nr_failed = 0; + int nr_failed; int nr_retry_pages = 0; int nr_large_failed = 0; int pass = 0; @@ -1474,38 +1565,45 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, trace_mm_migrate_pages_start(mode, reason); memset(&stats, 0, sizeof(stats)); + rc = migrate_hugetlbs(from, get_new_page, put_new_page, private, mode, reason, + &stats, &ret_folios); + if (rc < 0) + goto out; + nr_failed = rc; + split_folio_migration: - for (pass = 0; pass < 10 && (retry || large_retry); pass++) { + for (pass = 0; + pass < NR_MAX_MIGRATE_PAGES_RETRY && (retry || large_retry); + pass++) { retry = 0; large_retry = 0; thp_retry = 0; nr_retry_pages = 0; list_for_each_entry_safe(folio, folio2, from, lru) { + /* Retried hugetlb folios will be kept in list */ + if (folio_test_hugetlb(folio)) { + list_move_tail(&folio->lru, &ret_folios); + continue; + } + /* * Large folio statistics is based on the source large * folio. Capture required information that might get * lost during migration. */ - is_large = folio_test_large(folio) && !folio_test_hugetlb(folio); + is_large = folio_test_large(folio); is_thp = is_large && folio_test_pmd_mappable(folio); nr_pages = folio_nr_pages(folio); + cond_resched(); - if (folio_test_hugetlb(folio)) - rc = unmap_and_move_huge_page(get_new_page, - put_new_page, private, - &folio->page, pass > 2, mode, - reason, - &ret_folios); - else - rc = unmap_and_move(get_new_page, put_new_page, - private, folio, pass > 2, mode, - reason, &ret_folios); + rc = unmap_and_move(get_new_page, put_new_page, + private, folio, pass > 2, mode, + reason, &ret_folios); /* * The rules are: - * Success: non hugetlb folio will be freed, hugetlb - * folio will be put back + * Success: folio will be freed * -EAGAIN: stay on the from list * -ENOMEM: stay on the from list * -ENOSYS: stay on the from list @@ -1532,7 +1630,6 @@ split_folio_migration: stats.nr_thp_split += is_thp; break; } - /* Hugetlb migration is unsupported */ } else if (!no_split_folio_counting) { nr_failed++; } @@ -1626,8 +1723,8 @@ split_folio_migration: */ if (!list_empty(&split_folios)) { /* - * Move non-migrated folios (after 10 retries) to ret_folios - * to avoid migrating them again. + * Move non-migrated folios (after NR_MAX_MIGRATE_PAGES_RETRY + * retries) to ret_folios to avoid migrating them again. */ list_splice_init(from, &ret_folios); list_splice_init(&split_folios, from); -- cgit v1.2.3 From 42012e0436d44aeb2e68f11a28ddd0ad3f38b61f Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:38 +0800 Subject: migrate_pages: restrict number of pages to migrate in batch This is a preparation patch to batch the folio unmapping and moving for non-hugetlb folios. If we had batched the folio unmapping, all folios to be migrated would be unmapped before copying the contents and flags of the folios. If the folios that were passed to migrate_pages() were too many in unit of pages, the execution of the processes would be stopped for too long time, thus too long latency. For example, migrate_pages() syscall will call migrate_pages() with all folios of a process. To avoid this possible issue, in this patch, we restrict the number of pages to be migrated to be no more than HPAGE_PMD_NR. That is, the influence is at the same level of THP migration. Link: https://lkml.kernel.org/r/20230213123444.155149-4-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Baolin Wang Cc: Zi Yan Cc: Yang Shi Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Xin Hao Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 174 ++++++++++++++++++++++++++++++++++++----------------------- 1 file changed, 106 insertions(+), 68 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 586a32bdaa71..d436f35fa145 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1414,6 +1414,11 @@ static inline int try_split_folio(struct folio *folio, struct list_head *split_f return rc; } +#ifdef CONFIG_TRANSPARENT_HUGEPAGE +#define NR_MAX_BATCHED_MIGRATION HPAGE_PMD_NR +#else +#define NR_MAX_BATCHED_MIGRATION 512 +#endif #define NR_MAX_MIGRATE_PAGES_RETRY 10 struct migrate_pages_stats { @@ -1515,40 +1520,15 @@ static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, return nr_failed; } -/* - * migrate_pages - migrate the folios specified in a list, to the free folios - * supplied as the target for the page migration - * - * @from: The list of folios to be migrated. - * @get_new_page: The function used to allocate free folios to be used - * as the target of the folio migration. - * @put_new_page: The function used to free target folios if migration - * fails, or NULL if no special handling is necessary. - * @private: Private data to be passed on to get_new_page() - * @mode: The migration mode that specifies the constraints for - * folio migration, if any. - * @reason: The reason for folio migration. - * @ret_succeeded: Set to the number of folios migrated successfully if - * the caller passes a non-NULL pointer. - * - * The function returns after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no folios - * are movable any more because the list has become empty or no retryable folios - * exist any more. It is caller's responsibility to call putback_movable_pages() - * only if ret != 0. - * - * Returns the number of {normal folio, large folio, hugetlb} that were not - * migrated, or an error code. The number of large folio splits will be - * considered as the number of non-migrated large folio, no matter how many - * split folios of the large folio are migrated successfully. - */ -int migrate_pages(struct list_head *from, new_page_t get_new_page, +static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, free_page_t put_new_page, unsigned long private, - enum migrate_mode mode, int reason, unsigned int *ret_succeeded) + enum migrate_mode mode, int reason, struct list_head *ret_folios, + struct migrate_pages_stats *stats) { int retry = 1; int large_retry = 1; int thp_retry = 1; - int nr_failed; + int nr_failed = 0; int nr_retry_pages = 0; int nr_large_failed = 0; int pass = 0; @@ -1556,20 +1536,9 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, bool is_thp = false; struct folio *folio, *folio2; int rc, nr_pages; - LIST_HEAD(ret_folios); LIST_HEAD(split_folios); bool nosplit = (reason == MR_NUMA_MISPLACED); bool no_split_folio_counting = false; - struct migrate_pages_stats stats; - - trace_mm_migrate_pages_start(mode, reason); - - memset(&stats, 0, sizeof(stats)); - rc = migrate_hugetlbs(from, get_new_page, put_new_page, private, mode, reason, - &stats, &ret_folios); - if (rc < 0) - goto out; - nr_failed = rc; split_folio_migration: for (pass = 0; @@ -1581,12 +1550,6 @@ split_folio_migration: nr_retry_pages = 0; list_for_each_entry_safe(folio, folio2, from, lru) { - /* Retried hugetlb folios will be kept in list */ - if (folio_test_hugetlb(folio)) { - list_move_tail(&folio->lru, &ret_folios); - continue; - } - /* * Large folio statistics is based on the source large * folio. Capture required information that might get @@ -1600,15 +1563,14 @@ split_folio_migration: rc = unmap_and_move(get_new_page, put_new_page, private, folio, pass > 2, mode, - reason, &ret_folios); + reason, ret_folios); /* * The rules are: * Success: folio will be freed * -EAGAIN: stay on the from list * -ENOMEM: stay on the from list * -ENOSYS: stay on the from list - * Other errno: put on ret_folios list then splice to - * from list + * Other errno: put on ret_folios list */ switch(rc) { /* @@ -1625,17 +1587,17 @@ split_folio_migration: /* Large folio migration is unsupported */ if (is_large) { nr_large_failed++; - stats.nr_thp_failed += is_thp; + stats->nr_thp_failed += is_thp; if (!try_split_folio(folio, &split_folios)) { - stats.nr_thp_split += is_thp; + stats->nr_thp_split += is_thp; break; } } else if (!no_split_folio_counting) { nr_failed++; } - stats.nr_failed_pages += nr_pages; - list_move_tail(&folio->lru, &ret_folios); + stats->nr_failed_pages += nr_pages; + list_move_tail(&folio->lru, ret_folios); break; case -ENOMEM: /* @@ -1644,13 +1606,13 @@ split_folio_migration: */ if (is_large) { nr_large_failed++; - stats.nr_thp_failed += is_thp; + stats->nr_thp_failed += is_thp; /* Large folio NUMA faulting doesn't split to retry. */ if (!nosplit) { int ret = try_split_folio(folio, &split_folios); if (!ret) { - stats.nr_thp_split += is_thp; + stats->nr_thp_split += is_thp; break; } else if (reason == MR_LONGTERM_PIN && ret == -EAGAIN) { @@ -1668,17 +1630,17 @@ split_folio_migration: nr_failed++; } - stats.nr_failed_pages += nr_pages + nr_retry_pages; + stats->nr_failed_pages += nr_pages + nr_retry_pages; /* * There might be some split folios of fail-to-migrate large - * folios left in split_folios list. Move them back to migration + * folios left in split_folios list. Move them to ret_folios * list so that they could be put back to the right list by * the caller otherwise the folio refcnt will be leaked. */ - list_splice_init(&split_folios, from); + list_splice_init(&split_folios, ret_folios); /* nr_failed isn't updated for not used */ nr_large_failed += large_retry; - stats.nr_thp_failed += thp_retry; + stats->nr_thp_failed += thp_retry; goto out; case -EAGAIN: if (is_large) { @@ -1690,8 +1652,8 @@ split_folio_migration: nr_retry_pages += nr_pages; break; case MIGRATEPAGE_SUCCESS: - stats.nr_succeeded += nr_pages; - stats.nr_thp_succeeded += is_thp; + stats->nr_succeeded += nr_pages; + stats->nr_thp_succeeded += is_thp; break; default: /* @@ -1702,20 +1664,20 @@ split_folio_migration: */ if (is_large) { nr_large_failed++; - stats.nr_thp_failed += is_thp; + stats->nr_thp_failed += is_thp; } else if (!no_split_folio_counting) { nr_failed++; } - stats.nr_failed_pages += nr_pages; + stats->nr_failed_pages += nr_pages; break; } } } nr_failed += retry; nr_large_failed += large_retry; - stats.nr_thp_failed += thp_retry; - stats.nr_failed_pages += nr_retry_pages; + stats->nr_thp_failed += thp_retry; + stats->nr_failed_pages += nr_retry_pages; /* * Try to migrate split folios of fail-to-migrate large folios, no * nr_failed counting in this round, since all split folios of a @@ -1726,7 +1688,7 @@ split_folio_migration: * Move non-migrated folios (after NR_MAX_MIGRATE_PAGES_RETRY * retries) to ret_folios to avoid migrating them again. */ - list_splice_init(from, &ret_folios); + list_splice_init(from, ret_folios); list_splice_init(&split_folios, from); no_split_folio_counting = true; retry = 1; @@ -1734,6 +1696,82 @@ split_folio_migration: } rc = nr_failed + nr_large_failed; +out: + return rc; +} + +/* + * migrate_pages - migrate the folios specified in a list, to the free folios + * supplied as the target for the page migration + * + * @from: The list of folios to be migrated. + * @get_new_page: The function used to allocate free folios to be used + * as the target of the folio migration. + * @put_new_page: The function used to free target folios if migration + * fails, or NULL if no special handling is necessary. + * @private: Private data to be passed on to get_new_page() + * @mode: The migration mode that specifies the constraints for + * folio migration, if any. + * @reason: The reason for folio migration. + * @ret_succeeded: Set to the number of folios migrated successfully if + * the caller passes a non-NULL pointer. + * + * The function returns after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no folios + * are movable any more because the list has become empty or no retryable folios + * exist any more. It is caller's responsibility to call putback_movable_pages() + * only if ret != 0. + * + * Returns the number of {normal folio, large folio, hugetlb} that were not + * migrated, or an error code. The number of large folio splits will be + * considered as the number of non-migrated large folio, no matter how many + * split folios of the large folio are migrated successfully. + */ +int migrate_pages(struct list_head *from, new_page_t get_new_page, + free_page_t put_new_page, unsigned long private, + enum migrate_mode mode, int reason, unsigned int *ret_succeeded) +{ + int rc, rc_gather; + int nr_pages; + struct folio *folio, *folio2; + LIST_HEAD(folios); + LIST_HEAD(ret_folios); + struct migrate_pages_stats stats; + + trace_mm_migrate_pages_start(mode, reason); + + memset(&stats, 0, sizeof(stats)); + + rc_gather = migrate_hugetlbs(from, get_new_page, put_new_page, private, + mode, reason, &stats, &ret_folios); + if (rc_gather < 0) + goto out; +again: + nr_pages = 0; + list_for_each_entry_safe(folio, folio2, from, lru) { + /* Retried hugetlb folios will be kept in list */ + if (folio_test_hugetlb(folio)) { + list_move_tail(&folio->lru, &ret_folios); + continue; + } + + nr_pages += folio_nr_pages(folio); + if (nr_pages > NR_MAX_BATCHED_MIGRATION) + break; + } + if (nr_pages > NR_MAX_BATCHED_MIGRATION) + list_cut_before(&folios, from, &folio->lru); + else + list_splice_init(from, &folios); + rc = migrate_pages_batch(&folios, get_new_page, put_new_page, private, + mode, reason, &ret_folios, &stats); + list_splice_tail_init(&folios, &ret_folios); + if (rc < 0) { + rc_gather = rc; + goto out; + } + rc_gather += rc; + if (!list_empty(from)) + goto again; out: /* * Put the permanent failure folio back to migration list, they @@ -1746,7 +1784,7 @@ out: * are migrated successfully. */ if (list_empty(from)) - rc = 0; + rc_gather = 0; count_vm_events(PGMIGRATE_SUCCESS, stats.nr_succeeded); count_vm_events(PGMIGRATE_FAIL, stats.nr_failed_pages); @@ -1760,7 +1798,7 @@ out: if (ret_succeeded) *ret_succeeded = stats.nr_succeeded; - return rc; + return rc_gather; } struct page *alloc_migration_target(struct page *page, unsigned long private) -- cgit v1.2.3 From 64c8902ed4418317cd416c566f896bd4a92b2efc Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:39 +0800 Subject: migrate_pages: split unmap_and_move() to _unmap() and _move() This is a preparation patch to batch the folio unmapping and moving. In this patch, unmap_and_move() is split to migrate_folio_unmap() and migrate_folio_move(). So, we can batch _unmap() and _move() in different loops later. To pass some information between unmap and move, the original unused dst->mapping and dst->private are used. Link: https://lkml.kernel.org/r/20230213123444.155149-5-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Baolin Wang Reviewed-by: Xin Hao Cc: Zi Yan Cc: Yang Shi Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 169 ++++++++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 128 insertions(+), 41 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index d436f35fa145..5fd18a7cce62 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1027,11 +1027,53 @@ out: return rc; } -static int __unmap_and_move(struct folio *src, struct folio *dst, +/* + * To record some information during migration, we use some unused + * fields (mapping and private) of struct folio of the newly allocated + * destination folio. This is safe because nobody is using them + * except us. + */ +static void __migrate_folio_record(struct folio *dst, + unsigned long page_was_mapped, + struct anon_vma *anon_vma) +{ + dst->mapping = (void *)anon_vma; + dst->private = (void *)page_was_mapped; +} + +static void __migrate_folio_extract(struct folio *dst, + int *page_was_mappedp, + struct anon_vma **anon_vmap) +{ + *anon_vmap = (void *)dst->mapping; + *page_was_mappedp = (unsigned long)dst->private; + dst->mapping = NULL; + dst->private = NULL; +} + +/* Cleanup src folio upon migration success */ +static void migrate_folio_done(struct folio *src, + enum migrate_reason reason) +{ + /* + * Compaction can migrate also non-LRU pages which are + * not accounted to NR_ISOLATED_*. They can be recognized + * as __PageMovable + */ + if (likely(!__folio_test_movable(src))) + mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + + folio_is_file_lru(src), -folio_nr_pages(src)); + + if (reason != MR_MEMORY_FAILURE) + /* We release the page in page_handle_poison. */ + folio_put(src); +} + +static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force, enum migrate_mode mode) { int rc = -EAGAIN; - bool page_was_mapped = false; + int page_was_mapped = 0; struct anon_vma *anon_vma = NULL; bool is_lru = !__PageMovable(&src->page); @@ -1107,8 +1149,8 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, goto out_unlock; if (unlikely(!is_lru)) { - rc = move_to_new_folio(dst, src, mode); - goto out_unlock_both; + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return MIGRATEPAGE_UNMAP; } /* @@ -1133,11 +1175,42 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, VM_BUG_ON_FOLIO(folio_test_anon(src) && !folio_test_ksm(src) && !anon_vma, src); try_to_migrate(src, 0); - page_was_mapped = true; + page_was_mapped = 1; } - if (!folio_mapped(src)) - rc = move_to_new_folio(dst, src, mode); + if (!folio_mapped(src)) { + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return MIGRATEPAGE_UNMAP; + } + + if (page_was_mapped) + remove_migration_ptes(src, src, false); + +out_unlock_both: + folio_unlock(dst); +out_unlock: + /* Drop an anon_vma reference if we took one */ + if (anon_vma) + put_anon_vma(anon_vma); + folio_unlock(src); +out: + + return rc; +} + +static int __migrate_folio_move(struct folio *src, struct folio *dst, + enum migrate_mode mode) +{ + int rc; + int page_was_mapped = 0; + struct anon_vma *anon_vma = NULL; + bool is_lru = !__PageMovable(&src->page); + + __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); + + rc = move_to_new_folio(dst, src, mode); + if (unlikely(!is_lru)) + goto out_unlock_both; /* * When successful, push dst to LRU immediately: so that if it @@ -1160,12 +1233,10 @@ static int __unmap_and_move(struct folio *src, struct folio *dst, out_unlock_both: folio_unlock(dst); -out_unlock: /* Drop an anon_vma reference if we took one */ if (anon_vma) put_anon_vma(anon_vma); folio_unlock(src); -out: /* * If migration is successful, decrease refcount of dst, * which will not free the page because new page owner increased @@ -1177,19 +1248,15 @@ out: return rc; } -/* - * Obtain the lock on folio, remove all ptes and migrate the folio - * to the newly allocated folio in dst. - */ -static int unmap_and_move(new_page_t get_new_page, - free_page_t put_new_page, - unsigned long private, struct folio *src, - int force, enum migrate_mode mode, - enum migrate_reason reason, - struct list_head *ret) +/* Obtain the lock on page, remove all ptes. */ +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, + unsigned long private, struct folio *src, + struct folio **dstp, int force, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) { struct folio *dst; - int rc = MIGRATEPAGE_SUCCESS; + int rc = MIGRATEPAGE_UNMAP; struct page *newpage = NULL; if (!thp_migration_supported() && folio_test_transhuge(src)) @@ -1200,20 +1267,49 @@ static int unmap_and_move(new_page_t get_new_page, folio_clear_active(src); folio_clear_unevictable(src); /* free_pages_prepare() will clear PG_isolated. */ - goto out; + list_del(&src->lru); + migrate_folio_done(src, reason); + return MIGRATEPAGE_SUCCESS; } newpage = get_new_page(&src->page, private); if (!newpage) return -ENOMEM; dst = page_folio(newpage); + *dstp = dst; dst->private = NULL; - rc = __unmap_and_move(src, dst, force, mode); + rc = __migrate_folio_unmap(src, dst, force, mode); + if (rc == MIGRATEPAGE_UNMAP) + return rc; + + /* + * A folio that has not been unmapped will be restored to + * right list unless we want to retry. + */ + if (rc != -EAGAIN) + list_move_tail(&src->lru, ret); + + if (put_new_page) + put_new_page(&dst->page, private); + else + folio_put(dst); + + return rc; +} + +/* Migrate the folio to the newly allocated folio in dst. */ +static int migrate_folio_move(free_page_t put_new_page, unsigned long private, + struct folio *src, struct folio *dst, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) +{ + int rc; + + rc = __migrate_folio_move(src, dst, mode); if (rc == MIGRATEPAGE_SUCCESS) set_page_owner_migrate_reason(&dst->page, reason); -out: if (rc != -EAGAIN) { /* * A folio that has been migrated has all references @@ -1229,20 +1325,7 @@ out: * we want to retry. */ if (rc == MIGRATEPAGE_SUCCESS) { - /* - * Compaction can migrate also non-LRU folios which are - * not accounted to NR_ISOLATED_*. They can be recognized - * as __folio_test_movable - */ - if (likely(!__folio_test_movable(src))) - mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + - folio_is_file_lru(src), -folio_nr_pages(src)); - - if (reason != MR_MEMORY_FAILURE) - /* - * We release the folio in page_handle_poison. - */ - folio_put(src); + migrate_folio_done(src, reason); } else { if (rc != -EAGAIN) list_add_tail(&src->lru, ret); @@ -1534,7 +1617,7 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, int pass = 0; bool is_large = false; bool is_thp = false; - struct folio *folio, *folio2; + struct folio *folio, *folio2, *dst = NULL; int rc, nr_pages; LIST_HEAD(split_folios); bool nosplit = (reason == MR_NUMA_MISPLACED); @@ -1561,9 +1644,13 @@ split_folio_migration: cond_resched(); - rc = unmap_and_move(get_new_page, put_new_page, - private, folio, pass > 2, mode, - reason, ret_folios); + rc = migrate_folio_unmap(get_new_page, put_new_page, private, + folio, &dst, pass > 2, mode, + reason, ret_folios); + if (rc == MIGRATEPAGE_UNMAP) + rc = migrate_folio_move(put_new_page, private, + folio, dst, mode, + reason, ret_folios); /* * The rules are: * Success: folio will be freed -- cgit v1.2.3 From 5dfab109d5193e6c224d96cabf90e9cc2c039884 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:40 +0800 Subject: migrate_pages: batch _unmap and _move In this patch the _unmap and _move stage of the folio migration is batched. That for, previously, it is, for each folio _unmap() _move() Now, it is, for each folio _unmap() for each folio _move() Based on this, we can batch the TLB flushing and use some hardware accelerator to copy folios between batched _unmap and batched _move stages. Link: https://lkml.kernel.org/r/20230213123444.155149-6-ying.huang@intel.com Signed-off-by: "Huang, Ying" Tested-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Zi Yan Cc: Yang Shi Cc: Baolin Wang Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Xin Hao Cc: Minchan Kim Cc: Mike Kravetz Signed-off-by: Andrew Morton --- mm/migrate.c | 214 ++++++++++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 189 insertions(+), 25 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 5fd18a7cce62..ee3e21f1061c 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1051,6 +1051,33 @@ static void __migrate_folio_extract(struct folio *dst, dst->private = NULL; } +/* Restore the source folio to the original state upon failure */ +static void migrate_folio_undo_src(struct folio *src, + int page_was_mapped, + struct anon_vma *anon_vma, + struct list_head *ret) +{ + if (page_was_mapped) + remove_migration_ptes(src, src, false); + /* Drop an anon_vma reference if we took one */ + if (anon_vma) + put_anon_vma(anon_vma); + folio_unlock(src); + list_move_tail(&src->lru, ret); +} + +/* Restore the destination folio to the original state upon failure */ +static void migrate_folio_undo_dst(struct folio *dst, + free_page_t put_new_page, + unsigned long private) +{ + folio_unlock(dst); + if (put_new_page) + put_new_page(&dst->page, private); + else + folio_put(dst); +} + /* Cleanup src folio upon migration success */ static void migrate_folio_done(struct folio *src, enum migrate_reason reason) @@ -1069,8 +1096,8 @@ static void migrate_folio_done(struct folio *src, folio_put(src); } -static int __migrate_folio_unmap(struct folio *src, struct folio *dst, - int force, enum migrate_mode mode) +static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force, + bool avoid_force_lock, enum migrate_mode mode) { int rc = -EAGAIN; int page_was_mapped = 0; @@ -1097,6 +1124,17 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, if (current->flags & PF_MEMALLOC) goto out; + /* + * We have locked some folios and are going to wait to lock + * this folio. To avoid a potential deadlock, let's bail + * out and not do that. The locked folios will be moved and + * unlocked, then we can wait to lock this folio. + */ + if (avoid_force_lock) { + rc = -EDEADLOCK; + goto out; + } + folio_lock(src); } @@ -1205,10 +1243,20 @@ static int __migrate_folio_move(struct folio *src, struct folio *dst, int page_was_mapped = 0; struct anon_vma *anon_vma = NULL; bool is_lru = !__PageMovable(&src->page); + struct list_head *prev; __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); + prev = dst->lru.prev; + list_del(&dst->lru); rc = move_to_new_folio(dst, src, mode); + + if (rc == -EAGAIN) { + list_add(&dst->lru, prev); + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return rc; + } + if (unlikely(!is_lru)) goto out_unlock_both; @@ -1251,7 +1299,7 @@ out_unlock_both: /* Obtain the lock on page, remove all ptes. */ static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, unsigned long private, struct folio *src, - struct folio **dstp, int force, + struct folio **dstp, int force, bool avoid_force_lock, enum migrate_mode mode, enum migrate_reason reason, struct list_head *ret) { @@ -1279,7 +1327,7 @@ static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page *dstp = dst; dst->private = NULL; - rc = __migrate_folio_unmap(src, dst, force, mode); + rc = __migrate_folio_unmap(src, dst, force, avoid_force_lock, mode); if (rc == MIGRATEPAGE_UNMAP) return rc; @@ -1287,7 +1335,7 @@ static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page * A folio that has not been unmapped will be restored to * right list unless we want to retry. */ - if (rc != -EAGAIN) + if (rc != -EAGAIN && rc != -EDEADLOCK) list_move_tail(&src->lru, ret); if (put_new_page) @@ -1326,9 +1374,8 @@ static int migrate_folio_move(free_page_t put_new_page, unsigned long private, */ if (rc == MIGRATEPAGE_SUCCESS) { migrate_folio_done(src, reason); - } else { - if (rc != -EAGAIN) - list_add_tail(&src->lru, ret); + } else if (rc != -EAGAIN) { + list_add_tail(&src->lru, ret); if (put_new_page) put_new_page(&dst->page, private); @@ -1603,12 +1650,16 @@ static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, return nr_failed; } +/* + * migrate_pages_batch() first unmaps folios in the from list as many as + * possible, then move the unmapped folios. + */ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, free_page_t put_new_page, unsigned long private, enum migrate_mode mode, int reason, struct list_head *ret_folios, struct migrate_pages_stats *stats) { - int retry = 1; + int retry; int large_retry = 1; int thp_retry = 1; int nr_failed = 0; @@ -1617,13 +1668,19 @@ static int migrate_pages_batch(struct list_head *from, new_page_t get_new_page, int pass = 0; bool is_large = false; bool is_thp = false; - struct folio *folio, *folio2, *dst = NULL; - int rc, nr_pages; + struct folio *folio, *folio2, *dst = NULL, *dst2; + int rc, rc_saved, nr_pages; LIST_HEAD(split_folios); + LIST_HEAD(unmap_folios); + LIST_HEAD(dst_folios); bool nosplit = (reason == MR_NUMA_MISPLACED); bool no_split_folio_counting = false; + bool avoid_force_lock; -split_folio_migration: +retry: + rc_saved = 0; + avoid_force_lock = false; + retry = 1; for (pass = 0; pass < NR_MAX_MIGRATE_PAGES_RETRY && (retry || large_retry); pass++) { @@ -1645,16 +1702,15 @@ split_folio_migration: cond_resched(); rc = migrate_folio_unmap(get_new_page, put_new_page, private, - folio, &dst, pass > 2, mode, - reason, ret_folios); - if (rc == MIGRATEPAGE_UNMAP) - rc = migrate_folio_move(put_new_page, private, - folio, dst, mode, - reason, ret_folios); + folio, &dst, pass > 2, avoid_force_lock, + mode, reason, ret_folios); /* * The rules are: * Success: folio will be freed + * Unmap: folio will be put on unmap_folios list, + * dst folio put on dst_folios list * -EAGAIN: stay on the from list + * -EDEADLOCK: stay on the from list * -ENOMEM: stay on the from list * -ENOSYS: stay on the from list * Other errno: put on ret_folios list @@ -1689,7 +1745,7 @@ split_folio_migration: case -ENOMEM: /* * When memory is low, don't bother to try to migrate - * other folios, just exit. + * other folios, move unmapped folios, then exit. */ if (is_large) { nr_large_failed++; @@ -1728,7 +1784,19 @@ split_folio_migration: /* nr_failed isn't updated for not used */ nr_large_failed += large_retry; stats->nr_thp_failed += thp_retry; - goto out; + rc_saved = rc; + if (list_empty(&unmap_folios)) + goto out; + else + goto move; + case -EDEADLOCK: + /* + * The folio cannot be locked for potential deadlock. + * Go move (and unlock) all locked folios. Then we can + * try again. + */ + rc_saved = rc; + goto move; case -EAGAIN: if (is_large) { large_retry++; @@ -1742,6 +1810,15 @@ split_folio_migration: stats->nr_succeeded += nr_pages; stats->nr_thp_succeeded += is_thp; break; + case MIGRATEPAGE_UNMAP: + /* + * We have locked some folios, don't force lock + * to avoid deadlock. + */ + avoid_force_lock = true; + list_move_tail(&folio->lru, &unmap_folios); + list_add_tail(&dst->lru, &dst_folios); + break; default: /* * Permanent failure (-EBUSY, etc.): @@ -1765,12 +1842,95 @@ split_folio_migration: nr_large_failed += large_retry; stats->nr_thp_failed += thp_retry; stats->nr_failed_pages += nr_retry_pages; +move: + retry = 1; + for (pass = 0; + pass < NR_MAX_MIGRATE_PAGES_RETRY && (retry || large_retry); + pass++) { + retry = 0; + large_retry = 0; + thp_retry = 0; + nr_retry_pages = 0; + + dst = list_first_entry(&dst_folios, struct folio, lru); + dst2 = list_next_entry(dst, lru); + list_for_each_entry_safe(folio, folio2, &unmap_folios, lru) { + is_large = folio_test_large(folio); + is_thp = is_large && folio_test_pmd_mappable(folio); + nr_pages = folio_nr_pages(folio); + + cond_resched(); + + rc = migrate_folio_move(put_new_page, private, + folio, dst, mode, + reason, ret_folios); + /* + * The rules are: + * Success: folio will be freed + * -EAGAIN: stay on the unmap_folios list + * Other errno: put on ret_folios list + */ + switch(rc) { + case -EAGAIN: + if (is_large) { + large_retry++; + thp_retry += is_thp; + } else if (!no_split_folio_counting) { + retry++; + } + nr_retry_pages += nr_pages; + break; + case MIGRATEPAGE_SUCCESS: + stats->nr_succeeded += nr_pages; + stats->nr_thp_succeeded += is_thp; + break; + default: + if (is_large) { + nr_large_failed++; + stats->nr_thp_failed += is_thp; + } else if (!no_split_folio_counting) { + nr_failed++; + } + + stats->nr_failed_pages += nr_pages; + break; + } + dst = dst2; + dst2 = list_next_entry(dst, lru); + } + } + nr_failed += retry; + nr_large_failed += large_retry; + stats->nr_thp_failed += thp_retry; + stats->nr_failed_pages += nr_retry_pages; + + if (rc_saved) + rc = rc_saved; + else + rc = nr_failed + nr_large_failed; +out: + /* Cleanup remaining folios */ + dst = list_first_entry(&dst_folios, struct folio, lru); + dst2 = list_next_entry(dst, lru); + list_for_each_entry_safe(folio, folio2, &unmap_folios, lru) { + int page_was_mapped = 0; + struct anon_vma *anon_vma = NULL; + + __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); + migrate_folio_undo_src(folio, page_was_mapped, anon_vma, + ret_folios); + list_del(&dst->lru); + migrate_folio_undo_dst(dst, put_new_page, private); + dst = dst2; + dst2 = list_next_entry(dst, lru); + } + /* * Try to migrate split folios of fail-to-migrate large folios, no * nr_failed counting in this round, since all split folios of a * large folio is counted as 1 failure in the first round. */ - if (!list_empty(&split_folios)) { + if (rc >= 0 && !list_empty(&split_folios)) { /* * Move non-migrated folios (after NR_MAX_MIGRATE_PAGES_RETRY * retries) to ret_folios to avoid migrating them again. @@ -1778,12 +1938,16 @@ split_folio_migration: list_splice_init(from, ret_folios); list_splice_init(&split_folios, from); no_split_folio_counting = true; - retry = 1; - goto split_folio_migration; + goto retry; } - rc = nr_failed + nr_large_failed; -out: + /* + * We have unlocked all locked folios, so we can force lock now, let's + * try again. + */ + if (rc == -EDEADLOCK) + goto retry; + return rc; } -- cgit v1.2.3 From 80562ba0d8378e89fe5836c28ea56c2aab3014e8 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:41 +0800 Subject: migrate_pages: move migrate_folio_unmap() Just move the position of the functions. There's no any functionality change. This is to make it easier to review the next patch via putting code near its position in the next patch. Link: https://lkml.kernel.org/r/20230213123444.155149-7-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Zi Yan Cc: Yang Shi Cc: Baolin Wang Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Xin Hao Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 100 +++++++++++++++++++++++++++++------------------------------ 1 file changed, 50 insertions(+), 50 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index ee3e21f1061c..0c7488ebe248 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1236,6 +1236,56 @@ out: return rc; } +/* Obtain the lock on page, remove all ptes. */ +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, + unsigned long private, struct folio *src, + struct folio **dstp, int force, bool avoid_force_lock, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) +{ + struct folio *dst; + int rc = MIGRATEPAGE_UNMAP; + struct page *newpage = NULL; + + if (!thp_migration_supported() && folio_test_transhuge(src)) + return -ENOSYS; + + if (folio_ref_count(src) == 1) { + /* Folio was freed from under us. So we are done. */ + folio_clear_active(src); + folio_clear_unevictable(src); + /* free_pages_prepare() will clear PG_isolated. */ + list_del(&src->lru); + migrate_folio_done(src, reason); + return MIGRATEPAGE_SUCCESS; + } + + newpage = get_new_page(&src->page, private); + if (!newpage) + return -ENOMEM; + dst = page_folio(newpage); + *dstp = dst; + + dst->private = NULL; + rc = __migrate_folio_unmap(src, dst, force, avoid_force_lock, mode); + if (rc == MIGRATEPAGE_UNMAP) + return rc; + + /* + * A folio that has not been unmapped will be restored to + * right list unless we want to retry. + */ + if (rc != -EAGAIN && rc != -EDEADLOCK) + list_move_tail(&src->lru, ret); + + if (put_new_page) + put_new_page(&dst->page, private); + else + folio_put(dst); + + return rc; +} + static int __migrate_folio_move(struct folio *src, struct folio *dst, enum migrate_mode mode) { @@ -1296,56 +1346,6 @@ out_unlock_both: return rc; } -/* Obtain the lock on page, remove all ptes. */ -static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, - unsigned long private, struct folio *src, - struct folio **dstp, int force, bool avoid_force_lock, - enum migrate_mode mode, enum migrate_reason reason, - struct list_head *ret) -{ - struct folio *dst; - int rc = MIGRATEPAGE_UNMAP; - struct page *newpage = NULL; - - if (!thp_migration_supported() && folio_test_transhuge(src)) - return -ENOSYS; - - if (folio_ref_count(src) == 1) { - /* Folio was freed from under us. So we are done. */ - folio_clear_active(src); - folio_clear_unevictable(src); - /* free_pages_prepare() will clear PG_isolated. */ - list_del(&src->lru); - migrate_folio_done(src, reason); - return MIGRATEPAGE_SUCCESS; - } - - newpage = get_new_page(&src->page, private); - if (!newpage) - return -ENOMEM; - dst = page_folio(newpage); - *dstp = dst; - - dst->private = NULL; - rc = __migrate_folio_unmap(src, dst, force, avoid_force_lock, mode); - if (rc == MIGRATEPAGE_UNMAP) - return rc; - - /* - * A folio that has not been unmapped will be restored to - * right list unless we want to retry. - */ - if (rc != -EAGAIN && rc != -EDEADLOCK) - list_move_tail(&src->lru, ret); - - if (put_new_page) - put_new_page(&dst->page, private); - else - folio_put(dst); - - return rc; -} - /* Migrate the folio to the newly allocated folio in dst. */ static int migrate_folio_move(free_page_t put_new_page, unsigned long private, struct folio *src, struct folio *dst, -- cgit v1.2.3 From ebe75e4751063dce6f61b579b43de86dcf7b7462 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:42 +0800 Subject: migrate_pages: share more code between _unmap and _move This is a code cleanup patch to reduce the duplicated code between the _unmap and _move stages of migrate_pages(). No functionality change is expected. Link: https://lkml.kernel.org/r/20230213123444.155149-8-ying.huang@intel.com Signed-off-by: "Huang, Ying" Cc: Zi Yan Cc: Yang Shi Cc: Baolin Wang Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Xin Hao Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 207 ++++++++++++++++++++++++----------------------------------- 1 file changed, 85 insertions(+), 122 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 0c7488ebe248..00713ccb6643 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1055,6 +1055,7 @@ static void __migrate_folio_extract(struct folio *dst, static void migrate_folio_undo_src(struct folio *src, int page_was_mapped, struct anon_vma *anon_vma, + bool locked, struct list_head *ret) { if (page_was_mapped) @@ -1062,16 +1063,20 @@ static void migrate_folio_undo_src(struct folio *src, /* Drop an anon_vma reference if we took one */ if (anon_vma) put_anon_vma(anon_vma); - folio_unlock(src); - list_move_tail(&src->lru, ret); + if (locked) + folio_unlock(src); + if (ret) + list_move_tail(&src->lru, ret); } /* Restore the destination folio to the original state upon failure */ static void migrate_folio_undo_dst(struct folio *dst, + bool locked, free_page_t put_new_page, unsigned long private) { - folio_unlock(dst); + if (locked) + folio_unlock(dst); if (put_new_page) put_new_page(&dst->page, private); else @@ -1096,13 +1101,42 @@ static void migrate_folio_done(struct folio *src, folio_put(src); } -static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force, - bool avoid_force_lock, enum migrate_mode mode) +/* Obtain the lock on page, remove all ptes. */ +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, + unsigned long private, struct folio *src, + struct folio **dstp, int force, bool avoid_force_lock, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) { + struct folio *dst; int rc = -EAGAIN; + struct page *newpage = NULL; int page_was_mapped = 0; struct anon_vma *anon_vma = NULL; bool is_lru = !__PageMovable(&src->page); + bool locked = false; + bool dst_locked = false; + + if (!thp_migration_supported() && folio_test_transhuge(src)) + return -ENOSYS; + + if (folio_ref_count(src) == 1) { + /* Folio was freed from under us. So we are done. */ + folio_clear_active(src); + folio_clear_unevictable(src); + /* free_pages_prepare() will clear PG_isolated. */ + list_del(&src->lru); + migrate_folio_done(src, reason); + return MIGRATEPAGE_SUCCESS; + } + + newpage = get_new_page(&src->page, private); + if (!newpage) + return -ENOMEM; + dst = page_folio(newpage); + *dstp = dst; + + dst->private = NULL; if (!folio_trylock(src)) { if (!force || mode == MIGRATE_ASYNC) @@ -1137,6 +1171,7 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force folio_lock(src); } + locked = true; if (folio_test_writeback(src)) { /* @@ -1151,10 +1186,10 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force break; default: rc = -EBUSY; - goto out_unlock; + goto out; } if (!force) - goto out_unlock; + goto out; folio_wait_writeback(src); } @@ -1184,7 +1219,8 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force * This is much like races on refcount of oldpage: just don't BUG(). */ if (unlikely(!folio_trylock(dst))) - goto out_unlock; + goto out; + dst_locked = true; if (unlikely(!is_lru)) { __migrate_folio_record(dst, page_was_mapped, anon_vma); @@ -1206,7 +1242,7 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force if (!src->mapping) { if (folio_test_private(src)) { try_to_free_buffers(src); - goto out_unlock_both; + goto out; } } else if (folio_mapped(src)) { /* Establish migration ptes */ @@ -1221,73 +1257,25 @@ static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force return MIGRATEPAGE_UNMAP; } - if (page_was_mapped) - remove_migration_ptes(src, src, false); - -out_unlock_both: - folio_unlock(dst); -out_unlock: - /* Drop an anon_vma reference if we took one */ - if (anon_vma) - put_anon_vma(anon_vma); - folio_unlock(src); out: - - return rc; -} - -/* Obtain the lock on page, remove all ptes. */ -static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page, - unsigned long private, struct folio *src, - struct folio **dstp, int force, bool avoid_force_lock, - enum migrate_mode mode, enum migrate_reason reason, - struct list_head *ret) -{ - struct folio *dst; - int rc = MIGRATEPAGE_UNMAP; - struct page *newpage = NULL; - - if (!thp_migration_supported() && folio_test_transhuge(src)) - return -ENOSYS; - - if (folio_ref_count(src) == 1) { - /* Folio was freed from under us. So we are done. */ - folio_clear_active(src); - folio_clear_unevictable(src); - /* free_pages_prepare() will clear PG_isolated. */ - list_del(&src->lru); - migrate_folio_done(src, reason); - return MIGRATEPAGE_SUCCESS; - } - - newpage = get_new_page(&src->page, private); - if (!newpage) - return -ENOMEM; - dst = page_folio(newpage); - *dstp = dst; - - dst->private = NULL; - rc = __migrate_folio_unmap(src, dst, force, avoid_force_lock, mode); - if (rc == MIGRATEPAGE_UNMAP) - return rc; - /* * A folio that has not been unmapped will be restored to * right list unless we want to retry. */ - if (rc != -EAGAIN && rc != -EDEADLOCK) - list_move_tail(&src->lru, ret); + if (rc == -EAGAIN || rc == -EDEADLOCK) + ret = NULL; - if (put_new_page) - put_new_page(&dst->page, private); - else - folio_put(dst); + migrate_folio_undo_src(src, page_was_mapped, anon_vma, locked, ret); + migrate_folio_undo_dst(dst, dst_locked, put_new_page, private); return rc; } -static int __migrate_folio_move(struct folio *src, struct folio *dst, - enum migrate_mode mode) +/* Migrate the folio to the newly allocated folio in dst. */ +static int migrate_folio_move(free_page_t put_new_page, unsigned long private, + struct folio *src, struct folio *dst, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) { int rc; int page_was_mapped = 0; @@ -1300,12 +1288,8 @@ static int __migrate_folio_move(struct folio *src, struct folio *dst, list_del(&dst->lru); rc = move_to_new_folio(dst, src, mode); - - if (rc == -EAGAIN) { - list_add(&dst->lru, prev); - __migrate_folio_record(dst, page_was_mapped, anon_vma); - return rc; - } + if (rc) + goto out; if (unlikely(!is_lru)) goto out_unlock_both; @@ -1319,70 +1303,49 @@ static int __migrate_folio_move(struct folio *src, struct folio *dst, * unsuccessful, and other cases when a page has been temporarily * isolated from the unevictable LRU: but this case is the easiest. */ - if (rc == MIGRATEPAGE_SUCCESS) { - folio_add_lru(dst); - if (page_was_mapped) - lru_add_drain(); - } + folio_add_lru(dst); + if (page_was_mapped) + lru_add_drain(); if (page_was_mapped) - remove_migration_ptes(src, - rc == MIGRATEPAGE_SUCCESS ? dst : src, false); + remove_migration_ptes(src, dst, false); out_unlock_both: folio_unlock(dst); - /* Drop an anon_vma reference if we took one */ - if (anon_vma) - put_anon_vma(anon_vma); - folio_unlock(src); + set_page_owner_migrate_reason(&dst->page, reason); /* * If migration is successful, decrease refcount of dst, * which will not free the page because new page owner increased * refcounter. */ - if (rc == MIGRATEPAGE_SUCCESS) - folio_put(dst); - - return rc; -} - -/* Migrate the folio to the newly allocated folio in dst. */ -static int migrate_folio_move(free_page_t put_new_page, unsigned long private, - struct folio *src, struct folio *dst, - enum migrate_mode mode, enum migrate_reason reason, - struct list_head *ret) -{ - int rc; - - rc = __migrate_folio_move(src, dst, mode); - if (rc == MIGRATEPAGE_SUCCESS) - set_page_owner_migrate_reason(&dst->page, reason); - - if (rc != -EAGAIN) { - /* - * A folio that has been migrated has all references - * removed and will be freed. A folio that has not been - * migrated will have kept its references and be restored. - */ - list_del(&src->lru); - } + folio_put(dst); /* - * If migration is successful, releases reference grabbed during - * isolation. Otherwise, restore the folio to right list unless - * we want to retry. + * A folio that has been migrated has all references removed + * and will be freed. */ - if (rc == MIGRATEPAGE_SUCCESS) { - migrate_folio_done(src, reason); - } else if (rc != -EAGAIN) { - list_add_tail(&src->lru, ret); + list_del(&src->lru); + /* Drop an anon_vma reference if we took one */ + if (anon_vma) + put_anon_vma(anon_vma); + folio_unlock(src); + migrate_folio_done(src, reason); - if (put_new_page) - put_new_page(&dst->page, private); - else - folio_put(dst); + return rc; +out: + /* + * A folio that has not been migrated will be restored to + * right list unless we want to retry. + */ + if (rc == -EAGAIN) { + list_add(&dst->lru, prev); + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return rc; } + migrate_folio_undo_src(src, page_was_mapped, anon_vma, true, ret); + migrate_folio_undo_dst(dst, true, put_new_page, private); + return rc; } @@ -1918,9 +1881,9 @@ out: __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); migrate_folio_undo_src(folio, page_was_mapped, anon_vma, - ret_folios); + true, ret_folios); list_del(&dst->lru); - migrate_folio_undo_dst(dst, put_new_page, private); + migrate_folio_undo_dst(dst, true, put_new_page, private); dst = dst2; dst2 = list_next_entry(dst, lru); } -- cgit v1.2.3 From 7e12beb8ca2ac98b2ec42e0ea4b76cdc93b58654 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:43 +0800 Subject: migrate_pages: batch flushing TLB The TLB flushing will cost quite some CPU cycles during the folio migration in some situations. For example, when migrate a folio of a process with multiple active threads that run on multiple CPUs. After batching the _unmap and _move in migrate_pages(), the TLB flushing can be batched easily with the existing TLB flush batching mechanism. This patch implements that. We use the following test case to test the patch. On a 2-socket Intel server, - Run pmbench memory accessing benchmark - Run `migratepages` to migrate pages of pmbench between node 0 and node 1 back and forth. With the patch, the TLB flushing IPI reduces 99.1% during the test and the number of pages migrated successfully per second increases 291.7%. Haoxin helped to test the patchset on an ARM64 server with 128 cores, 2 NUMA nodes. Test results show that the page migration performance increases up to 78%. NOTE: TLB flushing is batched only for normal folios, not for THP folios. Because the overhead of TLB flushing for THP folios is much lower than that for normal folios (about 1/512 on x86 platform). Link: https://lkml.kernel.org/r/20230213123444.155149-9-ying.huang@intel.com Signed-off-by: "Huang, Ying" Tested-by: Xin Hao Reviewed-by: Zi Yan Reviewed-by: Xin Hao Cc: Yang Shi Cc: Baolin Wang Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Alistair Popple Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 00713ccb6643..2fa420e4f68c 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1248,7 +1248,7 @@ static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page /* Establish migration ptes */ VM_BUG_ON_FOLIO(folio_test_anon(src) && !folio_test_ksm(src) && !anon_vma, src); - try_to_migrate(src, 0); + try_to_migrate(src, TTU_BATCH_FLUSH); page_was_mapped = 1; } @@ -1806,6 +1806,9 @@ retry: stats->nr_thp_failed += thp_retry; stats->nr_failed_pages += nr_retry_pages; move: + /* Flush TLBs for all unmapped folios */ + try_to_unmap_flush(); + retry = 1; for (pass = 0; pass < NR_MAX_MIGRATE_PAGES_RETRY && (retry || large_retry); -- cgit v1.2.3 From 6f7d760e86fa84862d749e36ebd29abf31f4f883 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Mon, 13 Feb 2023 20:34:44 +0800 Subject: migrate_pages: move THP/hugetlb migration support check to simplify code This is a code cleanup patch, no functionality change is expected. After the change, the line number reduces especially in the long migrate_pages_batch(). Link: https://lkml.kernel.org/r/20230213123444.155149-10-ying.huang@intel.com Signed-off-by: "Huang, Ying" Suggested-by: Alistair Popple Reviewed-by: Zi Yan Cc: Yang Shi Cc: Baolin Wang Cc: Oscar Salvador Cc: Matthew Wilcox Cc: Bharata B Rao Cc: Xin Hao Cc: Minchan Kim Cc: Mike Kravetz Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> Signed-off-by: Andrew Morton --- mm/migrate.c | 83 ++++++++++++++++++++++++++---------------------------------- 1 file changed, 36 insertions(+), 47 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 2fa420e4f68c..ef68a1aff35c 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1117,9 +1117,6 @@ static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_new_page bool locked = false; bool dst_locked = false; - if (!thp_migration_supported() && folio_test_transhuge(src)) - return -ENOSYS; - if (folio_ref_count(src) == 1) { /* Folio was freed from under us. So we are done. */ folio_clear_active(src); @@ -1380,16 +1377,6 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, struct anon_vma *anon_vma = NULL; struct address_space *mapping = NULL; - /* - * Migratability of hugepages depends on architectures and their size. - * This check is necessary because some callers of hugepage migration - * like soft offline and memory hotremove don't walk through page - * tables or check whether the hugepage is pmd-based or not before - * kicking migration. - */ - if (!hugepage_migration_supported(page_hstate(hpage))) - return -ENOSYS; - if (folio_ref_count(src) == 1) { /* page was freed from under us. So we are done. */ folio_putback_active_hugetlb(src); @@ -1556,6 +1543,20 @@ static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, cond_resched(); + /* + * Migratability of hugepages depends on architectures and + * their size. This check is necessary because some callers + * of hugepage migration like soft offline and memory + * hotremove don't walk through page tables or check whether + * the hugepage is pmd-based or not before kicking migration. + */ + if (!hugepage_migration_supported(folio_hstate(folio))) { + nr_failed++; + stats->nr_failed_pages += nr_pages; + list_move_tail(&folio->lru, ret_folios); + continue; + } + rc = unmap_and_move_huge_page(get_new_page, put_new_page, private, &folio->page, pass > 2, mode, @@ -1565,16 +1566,9 @@ static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, * Success: hugetlb folio will be put back * -EAGAIN: stay on the from list * -ENOMEM: stay on the from list - * -ENOSYS: stay on the from list * Other errno: put on ret_folios list */ switch(rc) { - case -ENOSYS: - /* Hugetlb migration is unsupported */ - nr_failed++; - stats->nr_failed_pages += nr_pages; - list_move_tail(&folio->lru, ret_folios); - break; case -ENOMEM: /* * When memory is low, don't bother to try to migrate @@ -1664,6 +1658,28 @@ retry: cond_resched(); + /* + * Large folio migration might be unsupported or + * the allocation might be failed so we should retry + * on the same folio with the large folio split + * to normal folios. + * + * Split folios are put in split_folios, and + * we will migrate them after the rest of the + * list is processed. + */ + if (!thp_migration_supported() && is_thp) { + nr_large_failed++; + stats->nr_thp_failed++; + if (!try_split_folio(folio, &split_folios)) { + stats->nr_thp_split++; + continue; + } + stats->nr_failed_pages += nr_pages; + list_move_tail(&folio->lru, ret_folios); + continue; + } + rc = migrate_folio_unmap(get_new_page, put_new_page, private, folio, &dst, pass > 2, avoid_force_lock, mode, reason, ret_folios); @@ -1675,36 +1691,9 @@ retry: * -EAGAIN: stay on the from list * -EDEADLOCK: stay on the from list * -ENOMEM: stay on the from list - * -ENOSYS: stay on the from list * Other errno: put on ret_folios list */ switch(rc) { - /* - * Large folio migration might be unsupported or - * the allocation could've failed so we should retry - * on the same folio with the large folio split - * to normal folios. - * - * Split folios are put in split_folios, and - * we will migrate them after the rest of the - * list is processed. - */ - case -ENOSYS: - /* Large folio migration is unsupported */ - if (is_large) { - nr_large_failed++; - stats->nr_thp_failed += is_thp; - if (!try_split_folio(folio, &split_folios)) { - stats->nr_thp_split += is_thp; - break; - } - } else if (!no_split_folio_counting) { - nr_failed++; - } - - stats->nr_failed_pages += nr_pages; - list_move_tail(&folio->lru, ret_folios); - break; case -ENOMEM: /* * When memory is low, don't bother to try to migrate -- cgit v1.2.3 From f7f9c00dfafffd7a5a1a5685e2d874c64913e2ed Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Wed, 15 Feb 2023 18:39:35 +0800 Subject: mm: change to return bool for isolate_lru_page() The isolate_lru_page() can only return 0 or -EBUSY, and most users did not care about the negative error of isolate_lru_page(), except one user in add_page_for_migration(). So we can convert the isolate_lru_page() to return a boolean value, which can help to make the code more clear when checking the return value of isolate_lru_page(). Also convert all users' logic of checking the isolation state. No functional changes intended. Link: https://lkml.kernel.org/r/3074c1ab628d9dbf139b33f248a8bc253a3f95f0.1676424378.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Acked-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle) Acked-by: Linus Torvalds Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton --- mm/migrate.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index ef68a1aff35c..53010a142e7f 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2132,11 +2132,14 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, } } else { struct page *head; + bool isolated; head = compound_head(page); - err = isolate_lru_page(head); - if (err) + isolated = isolate_lru_page(head); + if (!isolated) { + err = -EBUSY; goto out_putpage; + } err = 1; list_add_tail(&head->lru, pagelist); @@ -2541,7 +2544,7 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) return 0; } - if (isolate_lru_page(page)) + if (!isolate_lru_page(page)) return 0; mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_is_file_lru(page), -- cgit v1.2.3 From 9747b9e92418b61c2281561e0651803f1fad0159 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Wed, 15 Feb 2023 18:39:36 +0800 Subject: mm: hugetlb: change to return bool for isolate_hugetlb() Now the isolate_hugetlb() only returns 0 or -EBUSY, and most users did not care about the negative value, thus we can convert the isolate_hugetlb() to return a boolean value to make code more clear when checking the hugetlb isolation state. Moreover converts 2 users which will consider the negative value returned by isolate_hugetlb(). No functional changes intended. [akpm@linux-foundation.org: shorten locked section, per SeongJae Park] Link: https://lkml.kernel.org/r/12a287c5bebc13df304387087bbecc6421510849.1676424378.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Acked-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Mike Kravetz Acked-by: Linus Torvalds Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton --- mm/migrate.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 53010a142e7f..2db546a0618c 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2095,6 +2095,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, struct vm_area_struct *vma; struct page *page; int err; + bool isolated; mmap_read_lock(mm); err = -EFAULT; @@ -2126,13 +2127,11 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, if (PageHuge(page)) { if (PageHead(page)) { - err = isolate_hugetlb(page_folio(page), pagelist); - if (!err) - err = 1; + isolated = isolate_hugetlb(page_folio(page), pagelist); + err = isolated ? 1 : -EBUSY; } } else { struct page *head; - bool isolated; head = compound_head(page); isolated = isolate_lru_page(head); -- cgit v1.2.3 From cd7755800eb54e8522f5e51f4e71e6494c1f1572 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Wed, 15 Feb 2023 18:39:37 +0800 Subject: mm: change to return bool for isolate_movable_page() Now the isolate_movable_page() can only return 0 or -EBUSY, and no users will care about the negative return value, thus we can convert the isolate_movable_page() to return a boolean value to make the code more clear when checking the movable page isolation state. No functional changes intended. [akpm@linux-foundation.org: remove unneeded comment, per Matthew] Link: https://lkml.kernel.org/r/cb877f73f4fff8d309611082ec740a7065b1ade0.1676424378.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Acked-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle) Acked-by: Linus Torvalds Reviewed-by: SeongJae Park Signed-off-by: Andrew Morton --- mm/migrate.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 2db546a0618c..9a101c7bb8ff 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -58,7 +58,7 @@ #include "internal.h" -int isolate_movable_page(struct page *page, isolate_mode_t mode) +bool isolate_movable_page(struct page *page, isolate_mode_t mode) { struct folio *folio = folio_get_nontail_page(page); const struct movable_operations *mops; @@ -119,14 +119,14 @@ int isolate_movable_page(struct page *page, isolate_mode_t mode) folio_set_isolated(folio); folio_unlock(folio); - return 0; + return true; out_no_isolated: folio_unlock(folio); out_putfolio: folio_put(folio); out: - return -EBUSY; + return false; } static void putback_movable_folio(struct folio *folio) -- cgit v1.2.3