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 <gregory.price@xxxxxxxxxxxx>
---
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
