+ mm-swap-optimise-get_shadow_from_swap_cache.patch added to -mm tree

+ mm-swap-optimise-get_shadow_from_swap_cache.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/swap: optimise get_shadow_from_swap_cache
has been added to the -mm tree.  Its filename is
     mm-swap-optimise-get_shadow_from_swap_cache.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-swap-optimise-get_shadow_from_swap_cache.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-swap-optimise-get_shadow_from_swap_cache.patch

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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Subject: mm/swap: optimise get_shadow_from_swap_cache

There's no need to get a reference to the page, just load the entry and
see if it's a shadow entry.

Link: https://lkml.kernel.org/r/20201112212641.27837-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dave Chinner <dchinner@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/swap_state.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/mm/swap_state.c~mm-swap-optimise-get_shadow_from_swap_cache
+++ a/mm/swap_state.c
@@ -113,11 +113,9 @@ void *get_shadow_from_swap_cache(swp_ent
 	pgoff_t idx = swp_offset(entry);
 	struct page *page;
 
-	page = find_get_entry(address_space, idx);
+	page = xa_load(&address_space->i_pages, idx);
 	if (xa_is_value(page))
 		return page;
-	if (page)
-		put_page(page);
 	return NULL;
 }
 
_

Patches currently in -mm which might be from willy@infradead.org are

mm-fix-readahead_page_batch-for-retry-entries.patch
mm-fix-madvise-willneed-performance-problem.patch
mm-page-flags-fix-comment.patch
mm-page_alloc-add-__free_pages-documentation.patch
mm-make-pagecache-tagged-lookups-return-only-head-pages.patch
mm-shmem-use-pagevec_lookup-in-shmem_unlock_mapping.patch
mm-swap-optimise-get_shadow_from_swap_cache.patch
mm-add-fgp_entry.patch
mm-filemap-rename-find_get_entry-to-mapping_get_entry.patch
mm-filemap-add-helper-for-finding-pages.patch
mm-filemap-add-mapping_seek_hole_data.patch
iomap-use-mapping_seek_hole_data.patch
mm-add-and-use-find_lock_entries.patch
mm-add-an-end-parameter-to-find_get_entries.patch
mm-add-an-end-parameter-to-pagevec_lookup_entries.patch
mm-remove-nr_entries-parameter-from-pagevec_lookup_entries.patch
mm-pass-pvec-directly-to-find_get_entries.patch
mm-remove-pagevec_lookup_entries.patch
mm-truncateshmem-handle-truncates-that-split-thps.patch
mm-filemap-return-only-head-pages-from-find_get_entries.patch
mm-introduce-memfd_secret-system-call-to-create-secret-memory-areas-fix.patch