diff mbox series

[2/2] mm/huge_memory.c: use head to emphasize the purpose of page

Message ID 20200110032610.26499-2-richardw.yang@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series [1/2] mm/huge_memory.c: use head to check huge zero page | expand

Commit Message

Wei Yang Jan. 10, 2020, 3:26 a.m. UTC 
During split huge page, it checks the property of the page. Currently we
do the check on page and head without emphasizing the check is on the
compound page. In case the page passed to split_huge_page_to_list is a
tail page, audience would take some time to think about whether the
check is on compound page or tail page itself.

To make it explicit, use head instead of page for those checks. After
this, audience would be more clear about the checks are on compound page
and the page is used to do the split and dump error message if failed.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
---
 mm/huge_memory.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

Comments

Kirill A . Shutemov Jan. 10, 2020, 11:56 p.m. UTC | #1 
On Fri, Jan 10, 2020 at 11:26:10AM +0800, Wei Yang wrote:
> During split huge page, it checks the property of the page. Currently we
> do the check on page and head without emphasizing the check is on the
> compound page. In case the page passed to split_huge_page_to_list is a
> tail page, audience would take some time to think about whether the
> check is on compound page or tail page itself.
> 
> To make it explicit, use head instead of page for those checks. After
> this, audience would be more clear about the checks are on compound page
> and the page is used to do the split and dump error message if failed.
> 
> Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
diff mbox series

Patch

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 90165f68cf13..69e623216211 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2688,7 +2688,7 @@  int split_huge_page_to_list(struct page *page, struct list_head *list)
 {
 	struct page *head = compound_head(page);
 	struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
-	struct deferred_split *ds_queue = get_deferred_split_queue(page);
+	struct deferred_split *ds_queue = get_deferred_split_queue(head);
 	struct anon_vma *anon_vma = NULL;
 	struct address_space *mapping = NULL;
 	int count, mapcount, extra_pins, ret;
@@ -2697,10 +2697,10 @@  int split_huge_page_to_list(struct page *page, struct list_head *list)
 	pgoff_t end;
 
 	VM_BUG_ON_PAGE(is_huge_zero_page(head), head);
-	VM_BUG_ON_PAGE(!PageLocked(page), page);
-	VM_BUG_ON_PAGE(!PageCompound(page), page);
+	VM_BUG_ON_PAGE(!PageLocked(head), head);
+	VM_BUG_ON_PAGE(!PageCompound(head), head);
 
-	if (PageWriteback(page))
+	if (PageWriteback(head))
 		return -EBUSY;
 
 	if (PageAnon(head)) {
@@ -2751,7 +2751,7 @@  int split_huge_page_to_list(struct page *page, struct list_head *list)
 		goto out_unlock;
 	}
 
-	mlocked = PageMlocked(page);
+	mlocked = PageMlocked(head);
 	unmap_page(head);
 	VM_BUG_ON_PAGE(compound_mapcount(head), head);
 
@@ -2785,10 +2785,10 @@  int split_huge_page_to_list(struct page *page, struct list_head *list)
 		}
 		spin_unlock(&ds_queue->split_queue_lock);
 		if (mapping) {
-			if (PageSwapBacked(page))
-				__dec_node_page_state(page, NR_SHMEM_THPS);
+			if (PageSwapBacked(head))
+				__dec_node_page_state(head, NR_SHMEM_THPS);
 			else
-				__dec_node_page_state(page, NR_FILE_THPS);
+				__dec_node_page_state(head, NR_FILE_THPS);
 		}
 
 		__split_huge_page(page, list, end, flags);