From a98a2f0c8ce1b2138cb8e3ae410444dedcc14809 Mon Sep 17 00:00:00 2001 From: Alistair Popple Date: Wed, 30 Jun 2021 18:54:16 -0700 Subject: mm/rmap: split migration into its own function Migration is currently implemented as a mode of operation for try_to_unmap_one() generally specified by passing the TTU_MIGRATION flag or in the case of splitting a huge anonymous page TTU_SPLIT_FREEZE. However it does not have much in common with the rest of the unmap functionality of try_to_unmap_one() and thus splitting it into a separate function reduces the complexity of try_to_unmap_one() making it more readable. Several simplifications can also be made in try_to_migrate_one() based on the following observations: - All users of TTU_MIGRATION also set TTU_IGNORE_MLOCK. - No users of TTU_MIGRATION ever set TTU_IGNORE_HWPOISON. - No users of TTU_MIGRATION ever set TTU_BATCH_FLUSH. TTU_SPLIT_FREEZE is a special case of migration used when splitting an anonymous page. This is most easily dealt with by calling the correct function from unmap_page() in mm/huge_memory.c - either try_to_migrate() for PageAnon or try_to_unmap(). Link: https://lkml.kernel.org/r/20210616105937.23201-5-apopple@nvidia.com Signed-off-by: Alistair Popple Reviewed-by: Christoph Hellwig Reviewed-by: Ralph Campbell Cc: Ben Skeggs Cc: Hugh Dickins Cc: Jason Gunthorpe Cc: John Hubbard Cc: "Matthew Wilcox (Oracle)" Cc: Peter Xu Cc: Shakeel Butt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/migrate.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index de47bdfbd2f8..a69f54bd92b9 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1109,7 +1109,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, /* Establish migration ptes */ VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma, page); - try_to_unmap(page, TTU_MIGRATION|TTU_IGNORE_MLOCK); + try_to_migrate(page, 0); page_was_mapped = 1; } @@ -1311,7 +1311,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, if (page_mapped(hpage)) { bool mapping_locked = false; - enum ttu_flags ttu = TTU_MIGRATION|TTU_IGNORE_MLOCK; + enum ttu_flags ttu = 0; if (!PageAnon(hpage)) { /* @@ -1328,7 +1328,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, ttu |= TTU_RMAP_LOCKED; } - try_to_unmap(hpage, ttu); + try_to_migrate(hpage, ttu); page_was_mapped = 1; if (mapping_locked) @@ -2602,7 +2602,6 @@ static void migrate_vma_prepare(struct migrate_vma *migrate) */ static void migrate_vma_unmap(struct migrate_vma *migrate) { - int flags = TTU_MIGRATION | TTU_IGNORE_MLOCK; const unsigned long npages = migrate->npages; const unsigned long start = migrate->start; unsigned long addr, i, restore = 0; @@ -2614,7 +2613,7 @@ static void migrate_vma_unmap(struct migrate_vma *migrate) continue; if (page_mapped(page)) { - try_to_unmap(page, flags); + try_to_migrate(page, 0); if (page_mapped(page)) goto restore; } -- cgit v1.2.3