From 9407d88f4781b0afd97c64d8fdb4291ccf50d6e3 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 12 May 2022 20:23:03 -0700 Subject: [PATCH] vmscan: move initialisation of mapping down 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. Link: https://lkml.kernel.org/r/20220504182857.4013401-13-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Signed-off-by: Andrew Morton --- mm/vmscan.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 972557e2fb920..725a291e9dad2 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1588,12 +1588,11 @@ retry: 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; @@ -1744,9 +1743,6 @@ retry: if (!add_to_swap(folio)) goto activate_locked_split; } - - /* Adding to swap updated mapping */ - mapping = page_mapping(page); } } else if (PageSwapBacked(page) && PageTransHuge(page)) { /* Split shmem THP */ @@ -1787,6 +1783,7 @@ retry: } } + mapping = folio_mapping(folio); if (folio_test_dirty(folio)) { /* * Only kswapd can writeback filesystem folios -- 2.39.5