add_page_for_migration presently does two actions: 1) validates the page is present and migratable 2) isolates the page from LRU and puts it into the migration list
Break add_page_for_migration into 2 functions: add_page_for_migration - isolate the page from LUR and add to list add_virt_page_for_migration - validate the page and call the above add_page_for_migration does not require the mm_struct and so can be re-used for a physical addressing version of move_pages Signed-off-by: Gregory Price <[email protected]> --- mm/migrate.c | 84 +++++++++++++++++++++++++++++++--------------------- 1 file changed, 50 insertions(+), 34 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index c27b1f8097d4..27071a07ffbb 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2066,6 +2066,46 @@ static int do_move_pages_to_node(struct list_head *pagelist, int node) return err; } +/* + * Isolates the page from the LRU and puts it into the given pagelist + * Returns: + * errno - if the page cannot be isolated + * 0 - when it doesn't have to be migrated because it is already on the + * target node + * 1 - when it has been queued + */ +static int add_page_for_migration(struct page *page, + struct folio *folio, + int node, + struct list_head *pagelist, + bool migrate_all) +{ + if (folio_is_zone_device(folio)) + return -ENOENT; + + if (folio_nid(folio) == node) + return 0; + + if (page_mapcount(page) > 1 && !migrate_all) + return -EACCES; + + if (folio_test_hugetlb(folio)) { + if (isolate_hugetlb(folio, pagelist)) + return 1; + return -EBUSY; + } + + if (!folio_isolate_lru(folio)) + return -EBUSY; + + list_add_tail(&folio->lru, pagelist); + node_stat_mod_folio(folio, + NR_ISOLATED_ANON + folio_is_file_lru(folio), + folio_nr_pages(folio)); + + return 1; +} + /* * Resolves the given address to a struct page, isolates it from the LRU and * puts it to the given pagelist. @@ -2075,19 +2115,19 @@ static int do_move_pages_to_node(struct list_head *pagelist, int node) * target node * 1 - when it has been queued */ -static int add_page_for_migration(struct mm_struct *mm, const void __user *p, - int node, struct list_head *pagelist, bool migrate_all) +static int add_virt_page_for_migration(struct mm_struct *mm, + const void __user *p, int node, struct list_head *pagelist, + bool migrate_all) { struct vm_area_struct *vma; unsigned long addr; struct page *page; struct folio *folio; - int err; + int err = -EFAULT; mmap_read_lock(mm); addr = (unsigned long)untagged_addr_remote(mm, p); - err = -EFAULT; vma = vma_lookup(mm, addr); if (!vma || !vma_migratable(vma)) goto out; @@ -2095,41 +2135,17 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p, /* FOLL_DUMP to ignore special (like zero) pages */ page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); - err = PTR_ERR(page); - if (IS_ERR(page)) - goto out; - err = -ENOENT; if (!page) goto out; - folio = page_folio(page); - if (folio_is_zone_device(folio)) - goto out_putfolio; - - err = 0; - if (folio_nid(folio) == node) - goto out_putfolio; + err = PTR_ERR(page); + if (IS_ERR(page)) + goto out; - err = -EACCES; - if (page_mapcount(page) > 1 && !migrate_all) - goto out_putfolio; + folio = page_folio(page); + err = add_page_for_migration(page, folio, node, pagelist, migrate_all); - err = -EBUSY; - if (folio_test_hugetlb(folio)) { - if (isolate_hugetlb(folio, pagelist)) - err = 1; - } else { - if (!folio_isolate_lru(folio)) - goto out_putfolio; - - err = 1; - list_add_tail(&folio->lru, pagelist); - node_stat_mod_folio(folio, - NR_ISOLATED_ANON + folio_is_file_lru(folio), - folio_nr_pages(folio)); - } -out_putfolio: /* * Either remove the duplicate refcount from folio_isolate_lru() * or drop the folio ref if it was not isolated. @@ -2229,7 +2245,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, * Errors in the page lookup or isolation are not fatal and we simply * report them via status */ - err = add_page_for_migration(mm, p, current_node, &pagelist, + err = add_virt_page_for_migration(mm, p, current_node, &pagelist, flags & MPOL_MF_MOVE_ALL); if (err > 0) { -- 2.39.1
