linux-kernel - [PATCH v4 03/16] mm/swap: Optimise get_shadow_from_swap

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Message-Id: <20201112212641.27837-4-willy@infradead.org>
Date:   Thu, 12 Nov 2020 21:26:28 +0000
From:   "Matthew Wilcox (Oracle)" <willy@...radead.org>
To:     linux-fsdevel@...r.kernel.org, linux-mm@...ck.org
Cc:     "Matthew Wilcox (Oracle)" <willy@...radead.org>,
        akpm@...ux-foundation.org, hughd@...gle.com, hch@....de,
        hannes@...xchg.org, yang.shi@...ux.alibaba.com,
        dchinner@...hat.com, linux-kernel@...r.kernel.org
Subject: [PATCH v4 03/16] 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.

Signed-off-by: Matthew Wilcox (Oracle) <willy@...radead.org>
---
 mm/swap_state.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/mm/swap_state.c b/mm/swap_state.c
index cf7b322a9abc..d2161154d873 100644
--- a/mm/swap_state.c
+++ b/mm/swap_state.c
@@ -113,11 +113,9 @@ void *get_shadow_from_swap_cache(swp_entry_t entry)
 	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;
 }
 
-- 
2.28.0