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From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-mm@kvack.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-fsdevel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Yang Shi <yang.shi@linux.alibaba.com>,
	Dave Chinner <dchinner@redhat.com>,
	linux-kernel@vger.kernel.org, Jan Kara <jack@suse.cz>,
	William Kucharski <william.kucharski@oracle.com>
Subject: [PATCH v3 02/12] mm/shmem: Use pagevec_lookup in shmem_unlock_mapping
Date: Mon, 26 Oct 2020 04:13:58 +0000
Message-ID: <20201026041408.25230-3-willy@infradead.org> (raw)
In-Reply-To: <20201026041408.25230-1-willy@infradead.org>

The comment shows that the reason for using find_get_entries() is now
stale; find_get_pages() will not return 0 if it hits a consecutive run
of swap entries, and I don't believe it has since 2011.  pagevec_lookup()
is a simpler function to use than find_get_pages(), so use it instead.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
---
 mm/shmem.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 537c137698f8..a33972126b60 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -842,7 +842,6 @@ unsigned long shmem_swap_usage(struct vm_area_struct *vma)
 void shmem_unlock_mapping(struct address_space *mapping)
 {
 	struct pagevec pvec;
-	pgoff_t indices[PAGEVEC_SIZE];
 	pgoff_t index = 0;
 
 	pagevec_init(&pvec);
@@ -850,16 +849,8 @@ void shmem_unlock_mapping(struct address_space *mapping)
 	 * Minor point, but we might as well stop if someone else SHM_LOCKs it.
 	 */
 	while (!mapping_unevictable(mapping)) {
-		/*
-		 * Avoid pagevec_lookup(): find_get_pages() returns 0 as if it
-		 * has finished, if it hits a row of PAGEVEC_SIZE swap entries.
-		 */
-		pvec.nr = find_get_entries(mapping, index,
-					   PAGEVEC_SIZE, pvec.pages, indices);
-		if (!pvec.nr)
+		if (!pagevec_lookup(&pvec, mapping, &index))
 			break;
-		index = indices[pvec.nr - 1] + 1;
-		pagevec_remove_exceptionals(&pvec);
 		check_move_unevictable_pages(&pvec);
 		pagevec_release(&pvec);
 		cond_resched();
-- 
2.28.0


  parent reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-26  4:13 [PATCH v3 00/12] Overhaul multi-page lookups for THP Matthew Wilcox (Oracle)
2020-10-26  4:13 ` [PATCH v3 01/12] mm: Make pagecache tagged lookups return only head pages Matthew Wilcox (Oracle)
2020-10-28  7:50   ` Mike Rapoport
2020-11-12 17:41     ` Matthew Wilcox
2020-11-12 19:11       ` Mike Rapoport
2020-10-26  4:13 ` Matthew Wilcox (Oracle) [this message]
2020-10-26  4:13 ` [PATCH v3 03/12] mm/filemap: Add helper for finding pages Matthew Wilcox (Oracle)
2020-10-27 18:56   ` Christoph Hellwig
2020-11-12 14:25     ` Matthew Wilcox
2020-10-26  4:14 ` [PATCH v3 04/12] mm/filemap: Add mapping_seek_hole_data Matthew Wilcox (Oracle)
2020-10-26 10:48   ` Jan Kara
2020-10-26 12:17     ` Matthew Wilcox
2020-10-26 14:49       ` Jan Kara
2020-10-27 18:58   ` Christoph Hellwig
2020-10-27 20:04     ` Matthew Wilcox
2020-10-28  6:40       ` Christoph Hellwig
2020-10-26  4:14 ` [PATCH v3 05/12] mm: Add and use find_lock_entries Matthew Wilcox (Oracle)
2020-10-26  4:14 ` [PATCH v3 06/12] mm: Add an 'end' parameter to find_get_entries Matthew Wilcox (Oracle)
2020-10-26  4:14 ` [PATCH v3 07/12] mm: Add an 'end' parameter to pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-10-26  4:14 ` [PATCH v3 08/12] mm: Remove nr_entries parameter from pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-10-26  4:14 ` [PATCH v3 09/12] mm: Pass pvec directly to find_get_entries Matthew Wilcox (Oracle)
2020-10-26  4:14 ` [PATCH v3 10/12] mm: Remove pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-10-26  4:14 ` [PATCH v3 11/12] mm/truncate,shmem: Handle truncates that split THPs Matthew Wilcox (Oracle)
2020-10-26 11:05   ` Jan Kara
2020-10-26  4:14 ` [PATCH v3 12/12] mm/filemap: Return only head pages from find_get_entries Matthew Wilcox (Oracle)

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