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 | 79 ++++++++++++++++++++++++++++++----------------------
1 file changed, 46 insertions(+), 33 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index 6ecb1e68c34a..3506b8202937 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2042,52 +2042,33 @@ static int do_move_pages_to_node(struct list_head *pagelist, int node)
}
/*
- * Resolves the given address to a struct page, isolates it from the LRU and
- * puts it to the given pagelist.
+ * Isolates the page from the LRU and puts it into the given pagelist
* Returns:
* errno - if the page cannot be found/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 mm_struct *mm, const void __user *p,
- int node, struct list_head *pagelist, bool migrate_all)
+static int add_page_for_migration(struct page *page, int node,
+ struct list_head *pagelist, bool migrate_all)
{
- struct vm_area_struct *vma;
- unsigned long addr;
- struct page *page;
int err;
bool isolated;
- 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;
-
- /* 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;
if (is_zone_device_page(page))
- goto out_putpage;
+ goto out;
err = 0;
if (page_to_nid(page) == node)
- goto out_putpage;
+ goto out;
err = -EACCES;
if (page_mapcount(page) > 1 && !migrate_all)
- goto out_putpage;
+ goto out;
if (PageHuge(page)) {
if (PageHead(page)) {
@@ -2101,7 +2082,7 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p,
isolated = isolate_lru_page(head);
if (!isolated) {
err = -EBUSY;
- goto out_putpage;
+ goto out;
}
err = 1;
@@ -2110,12 +2091,44 @@ static int add_page_for_migration(struct mm_struct *mm, const void __user *p,
NR_ISOLATED_ANON + page_is_file_lru(head),
thp_nr_pages(head));
}
-out_putpage:
- /*
- * Either remove the duplicate refcount from
- * isolate_lru_page() or drop the page ref if it was
- * not isolated.
- */
+out:
+ return err;
+}
+
+/*
+ * Resolves the given address to a struct page, isolates it from the LRU and
+ * puts it to the given pagelist.
+ * Returns:
+ * errno - if the page cannot be found/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_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;
+ int err = -EFAULT;
+
+ mmap_read_lock(mm);
+ addr = (unsigned long)untagged_addr_remote(mm, p);
+
+ vma = vma_lookup(mm, addr);
+ if (!vma || !vma_migratable(vma))
+ goto out;
+
+ /* 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 = add_page_for_migration(page, node, pagelist, migrate_all);
+
put_page(page);
out:
mmap_read_unlock(mm);
@@ -2201,7 +2214,7 @@ 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
