Commit 46be67b4 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle) Committed by Linus Torvalds
Browse files

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: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: default avatarVishal Verma <vishal.l.verma@intel.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 7716506a

mm/filemap.c

+0 −13
Original line number Diff line number Diff line
@@ -142,17 +142,6 @@ static void page_cache_delete(struct address_space *mapping, 


	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(struct page *page, 
		if (xas_error(&xas))

			goto unlock;



		if (old)

			mapping->nrexceptional--;

		mapping->nrpages++;



		/* hugetlb pages do not participate in page cache accounting */

mm/swap_state.c

+0 −4
Original line number Diff line number Diff line
@@ -132,7 +132,6 @@ int add_to_swap_cache(struct page *page, swp_entry_t entry, 
			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 page *page, 
		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 type, unsigned long begin, 
			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 */

mm/truncate.c

+0 −1
Original line number Diff line number Diff line
@@ -40,7 +40,6 @@ static inline void __clear_shadow_entry(struct address_space *mapping, 
	if (xas_load(&xas) != entry)

		return;

	xas_store(&xas, NULL);

	mapping->nrexceptional--;

}



static void clear_shadow_entry(struct address_space *mapping, pgoff_t index,

mm/workingset.c

+0 −1
Original line number Diff line number Diff line
@@ -554,7 +554,6 @@ static enum lru_status shadow_lru_isolate(struct list_head *item, 
		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);