Removes a lot of calls to compound_head(). Also remove a VM_BUG_ON that
can never trigger as the PageAnon bit is the bottom bit of page->mapping.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
mm/migrate.c | 75 ++++++++++++++++++++++++++--------------------------
1 file changed, 37 insertions(+), 38 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index 6a1597c92261..3cd1fdb5f572 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -976,17 +976,15 @@ static int move_to_new_folio(struct folio *dst, struct folio *src,
return rc;
}
-static int __unmap_and_move(struct page *page, struct page *newpage,
+static int __unmap_and_move(struct folio *src, struct folio *dst,
int force, enum migrate_mode mode)
{
- struct folio *folio = page_folio(page);
- struct folio *dst = page_folio(newpage);
int rc = -EAGAIN;
bool page_was_mapped = false;
struct anon_vma *anon_vma = NULL;
- bool is_lru = !__PageMovable(page);
+ bool is_lru = !__PageMovable(&src->page);
- if (!trylock_page(page)) {
+ if (!folio_trylock(src)) {
if (!force || mode == MIGRATE_ASYNC)
goto out;
@@ -1006,10 +1004,10 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
if (current->flags & PF_MEMALLOC)
goto out;
- lock_page(page);
+ folio_lock(src);
}
- if (PageWriteback(page)) {
+ if (folio_test_writeback(src)) {
/*
* Only in the case of a full synchronous migration is it
* necessary to wait for PageWriteback. In the async case,
@@ -1026,12 +1024,12 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
}
if (!force)
goto out_unlock;
- wait_on_page_writeback(page);
+ folio_wait_writeback(src);
}
/*
- * By try_to_migrate(), page->mapcount goes down to 0 here. In this case,
- * we cannot notice that anon_vma is freed while we migrates a page.
+ * By try_to_migrate(), src->mapcount goes down to 0 here. In this case,
+ * we cannot notice that anon_vma is freed while we migrate a page.
* This get_anon_vma() delays freeing anon_vma pointer until the end
* of migration. File cache pages are no problem because of page_lock()
* File Caches may use write_page() or lock_page() in migration, then,
@@ -1043,22 +1041,22 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
* because that implies that the anon page is no longer mapped
* (and cannot be remapped so long as we hold the page lock).
*/
- if (PageAnon(page) && !PageKsm(page))
- anon_vma = page_get_anon_vma(page);
+ if (folio_test_anon(src) && !folio_test_ksm(src))
+ anon_vma = page_get_anon_vma(&src->page);
/*
* Block others from accessing the new page when we get around to
* establishing additional references. We are usually the only one
- * holding a reference to newpage at this point. We used to have a BUG
- * here if trylock_page(newpage) fails, but would like to allow for
- * cases where there might be a race with the previous use of newpage.
+ * holding a reference to dst at this point. We used to have a BUG
+ * here if folio_trylock(dst) fails, but would like to allow for
+ * cases where there might be a race with the previous use of dst.
* This is much like races on refcount of oldpage: just don't BUG().
*/
- if (unlikely(!trylock_page(newpage)))
+ if (unlikely(!folio_trylock(dst)))
goto out_unlock;
if (unlikely(!is_lru)) {
- rc = move_to_new_folio(dst, folio, mode);
+ rc = move_to_new_folio(dst, src, mode);
goto out_unlock_both;
}
@@ -1066,7 +1064,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
* Corner case handling:
* 1. When a new swap-cache page is read into, it is added to the LRU
* and treated as swapcache but it has no rmap yet.
- * Calling try_to_unmap() against a page->mapping==NULL page will
+ * Calling try_to_unmap() against a src->mapping==NULL page will
* trigger a BUG. So handle it here.
* 2. An orphaned page (see truncate_cleanup_page) might have
* fs-private metadata. The page can be picked up due to memory
@@ -1074,57 +1072,56 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
* invisible to the vm, so the page can not be migrated. So try to
* free the metadata, so the page can be freed.
*/
- if (!page->mapping) {
- VM_BUG_ON_PAGE(PageAnon(page), page);
- if (page_has_private(page)) {
- try_to_free_buffers(folio);
+ if (!src->mapping) {
+ if (folio_test_private(src)) {
+ try_to_free_buffers(src);
goto out_unlock_both;
}
- } else if (page_mapped(page)) {
+ } else if (folio_mapped(src)) {
/* Establish migration ptes */
- VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma,
- page);
- try_to_migrate(folio, 0);
+ VM_BUG_ON_FOLIO(folio_test_anon(src) &&
+ !folio_test_ksm(src) && !anon_vma, src);
+ try_to_migrate(src, 0);
page_was_mapped = true;
}
- if (!page_mapped(page))
- rc = move_to_new_folio(dst, folio, mode);
+ if (!folio_mapped(src))
+ rc = move_to_new_folio(dst, src, mode);
/*
- * When successful, push newpage to LRU immediately: so that if it
+ * When successful, push dst to LRU immediately: so that if it
* turns out to be an mlocked page, remove_migration_ptes() will
- * automatically build up the correct newpage->mlock_count for it.
+ * automatically build up the correct dst->mlock_count for it.
*
* We would like to do something similar for the old page, when
* 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) {
- lru_cache_add(newpage);
+ folio_add_lru(dst);
if (page_was_mapped)
lru_add_drain();
}
if (page_was_mapped)
- remove_migration_ptes(folio,
- rc == MIGRATEPAGE_SUCCESS ? dst : folio, false);
+ remove_migration_ptes(src,
+ rc == MIGRATEPAGE_SUCCESS ? dst : src, false);
out_unlock_both:
- unlock_page(newpage);
+ folio_unlock(dst);
out_unlock:
/* Drop an anon_vma reference if we took one */
if (anon_vma)
put_anon_vma(anon_vma);
- unlock_page(page);
+ folio_unlock(src);
out:
/*
- * If migration is successful, decrease refcount of the newpage,
+ * If migration is successful, decrease refcount of dst,
* which will not free the page because new page owner increased
* refcounter.
*/
if (rc == MIGRATEPAGE_SUCCESS)
- put_page(newpage);
+ folio_put(dst);
return rc;
}
@@ -1140,6 +1137,7 @@ static int unmap_and_move(new_page_t get_new_page,
enum migrate_reason reason,
struct list_head *ret)
{
+ struct folio *dst, *src = page_folio(page);
int rc = MIGRATEPAGE_SUCCESS;
struct page *newpage = NULL;
@@ -1157,9 +1155,10 @@ static int unmap_and_move(new_page_t get_new_page,
newpage = get_new_page(page, private);
if (!newpage)
return -ENOMEM;
+ dst = page_folio(newpage);
newpage->private = 0;
- rc = __unmap_and_move(page, newpage, force, mode);
+ rc = __unmap_and_move(src, dst, force, mode);
if (rc == MIGRATEPAGE_SUCCESS)
set_page_owner_migrate_reason(newpage, reason);
--
2.35.1
