diff mbox series

[002/143] mm: stop accounting shadow entries

Message ID 20210505013248.5s3M8UuFQ%akpm@linux-foundation.org (mailing list archive)
State New
Headers show
Series [001/143] mm: introduce and use mapping_empty() | expand

Commit Message

Andrew Morton May 5, 2021, 1:32 a.m. UTC
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: mm: stop accounting shadow entries

We no longer need to keep track of how many shadow entries are present in
a mapping.  This saves a few writes to the inode and memory barriers.

Link: https://lkml.kernel.org/r/20201026151849.24232-3-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Vishal Verma <vishal.l.verma@intel.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/filemap.c    |   13 -------------
 mm/swap_state.c |    4 ----
 mm/truncate.c   |    1 -
 mm/workingset.c |    1 -
 4 files changed, 19 deletions(-)
diff mbox series

Patch

--- a/mm/filemap.c~mm-stop-accounting-shadow-entries
+++ a/mm/filemap.c
@@ -142,17 +142,6 @@  static void page_cache_delete(struct add
 
 	page->mapping = NULL;
 	/* Leave page->index set: truncation lookup relies upon it */
-
-	if (shadow) {
-		mapping->nrexceptional += nr;
-		/*
-		 * Make sure the nrexceptional update is committed before
-		 * the nrpages update so that final truncate racing
-		 * with reclaim does not see both counters 0 at the
-		 * same time and miss a shadow entry.
-		 */
-		smp_wmb();
-	}
 	mapping->nrpages -= nr;
 }
 
@@ -925,8 +914,6 @@  noinline int __add_to_page_cache_locked(
 		if (xas_error(&xas))
 			goto unlock;
 
-		if (old)
-			mapping->nrexceptional--;
 		mapping->nrpages++;
 
 		/* hugetlb pages do not participate in page cache accounting */
--- a/mm/swap_state.c~mm-stop-accounting-shadow-entries
+++ a/mm/swap_state.c
@@ -132,7 +132,6 @@  int add_to_swap_cache(struct page *page,
 			xas_store(&xas, page);
 			xas_next(&xas);
 		}
-		address_space->nrexceptional -= nr_shadows;
 		address_space->nrpages += nr;
 		__mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr);
 		__mod_lruvec_page_state(page, NR_SWAPCACHE, nr);
@@ -172,8 +171,6 @@  void __delete_from_swap_cache(struct pag
 		xas_next(&xas);
 	}
 	ClearPageSwapCache(page);
-	if (shadow)
-		address_space->nrexceptional += nr;
 	address_space->nrpages -= nr;
 	__mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, -nr);
 	__mod_lruvec_page_state(page, NR_SWAPCACHE, -nr);
@@ -275,7 +272,6 @@  void clear_shadow_from_swap_cache(int ty
 			xas_store(&xas, NULL);
 			nr_shadows++;
 		}
-		address_space->nrexceptional -= nr_shadows;
 		xa_unlock_irq(&address_space->i_pages);
 
 		/* search the next swapcache until we meet end */
--- a/mm/truncate.c~mm-stop-accounting-shadow-entries
+++ a/mm/truncate.c
@@ -40,7 +40,6 @@  static inline void __clear_shadow_entry(
 	if (xas_load(&xas) != entry)
 		return;
 	xas_store(&xas, NULL);
-	mapping->nrexceptional--;
 }
 
 static void clear_shadow_entry(struct address_space *mapping, pgoff_t index,
--- a/mm/workingset.c~mm-stop-accounting-shadow-entries
+++ a/mm/workingset.c
@@ -554,7 +554,6 @@  static enum lru_status shadow_lru_isolat
 		goto out_invalid;
 	if (WARN_ON_ONCE(node->count != node->nr_values))
 		goto out_invalid;
-	mapping->nrexceptional -= node->nr_values;
 	xa_delete_node(node, workingset_update_node);
 	__inc_lruvec_kmem_state(node, WORKINGSET_NODERECLAIM);