Now that we don't interrogate the BDI for congestion, we can delay looking
up the folio's mapping until we've got further through the function,
reducing register pressure and saving a call to folio_mapping for folios
we're adding to the swap cache.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
mm/vmscan.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 0368ea3e9880..9ac2583ca5e5 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1568,12 +1568,11 @@ static unsigned int shrink_page_list(struct list_head *page_list,
stat->nr_unqueued_dirty += nr_pages;
/*
- * Treat this page as congested if the underlying BDI is or if
+ * Treat this page as congested if
* pages are cycling through the LRU so quickly that the
* pages marked for immediate reclaim are making it to the
* end of the LRU a second time.
*/
- mapping = page_mapping(page);
if (writeback && PageReclaim(page))
stat->nr_congested += nr_pages;
@@ -1725,9 +1724,6 @@ static unsigned int shrink_page_list(struct list_head *page_list,
}
may_enter_fs = true;
-
- /* Adding to swap updated mapping */
- mapping = page_mapping(page);
}
} else if (PageSwapBacked(page) && PageTransHuge(page)) {
/* Split shmem THP */
@@ -1768,6 +1764,7 @@ static unsigned int shrink_page_list(struct list_head *page_list,
}
}
+ mapping = folio_mapping(folio);
if (folio_test_dirty(folio)) {
/*
* Only kswapd can writeback filesystem folios
--
2.34.1
