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From: Matthew Wilcox <willy@infradead.org>
To: linux-fsdevel@vger.kernel.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org,
	linux-btrfs@vger.kernel.org, linux-erofs@lists.ozlabs.org,
	linux-ext4@vger.kernel.org,
	linux-f2fs-devel@lists.sourceforge.net,
	linux-xfs@vger.kernel.org, cluster-devel@redhat.com,
	ocfs2-devel@oss.oracle.com
Subject: [PATCH 03/12] readahead: Put pages in cache earlier
Date: Fri, 24 Jan 2020 17:35:44 -0800
Message-ID: <20200125013553.24899-4-willy@infradead.org> (raw)
In-Reply-To: <20200125013553.24899-1-willy@infradead.org>

From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

At allocation time, put the pages in the cache unless we're using
->readpages.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: linux-btrfs@vger.kernel.org
Cc: linux-erofs@lists.ozlabs.org
Cc: linux-ext4@vger.kernel.org
Cc: linux-f2fs-devel@lists.sourceforge.net
Cc: linux-xfs@vger.kernel.org
Cc: cluster-devel@redhat.com
Cc: ocfs2-devel@oss.oracle.com
---
 mm/readahead.c | 51 +++++++++++++++++++++++++++++++-------------------
 1 file changed, 32 insertions(+), 19 deletions(-)

diff --git a/mm/readahead.c b/mm/readahead.c
index fc77d13af556..5a6676640f20 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -114,10 +114,10 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages,
 EXPORT_SYMBOL(read_cache_pages);
 
 static void read_pages(struct address_space *mapping, struct file *filp,
-		struct list_head *pages, unsigned int nr_pages, gfp_t gfp)
+		struct list_head *pages, pgoff_t start,
+		unsigned int nr_pages)
 {
 	struct blk_plug plug;
-	unsigned page_idx;
 
 	blk_start_plug(&plug);
 
@@ -125,18 +125,17 @@ static void read_pages(struct address_space *mapping, struct file *filp,
 		mapping->a_ops->readpages(filp, mapping, pages, nr_pages);
 		/* Clean up the remaining pages */
 		put_pages_list(pages);
-		goto out;
-	}
+	} else {
+		struct page *page;
+		unsigned long index;
 
-	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
-		struct page *page = lru_to_page(pages);
-		list_del(&page->lru);
-		if (!add_to_page_cache_lru(page, mapping, page->index, gfp))
+		xa_for_each_range(&mapping->i_pages, index, page, start,
+				start + nr_pages - 1) {
 			mapping->a_ops->readpage(filp, page);
-		put_page(page);
+			put_page(page);
+		}
 	}
 
-out:
 	blk_finish_plug(&plug);
 }
 
@@ -157,9 +156,11 @@ unsigned long __do_page_cache_readahead(struct address_space *mapping,
 	unsigned long end_index;	/* The last page we want to read */
 	LIST_HEAD(page_pool);
 	int page_idx;
+	pgoff_t page_offset;
 	unsigned long nr_pages = 0;
 	loff_t isize = i_size_read(inode);
 	gfp_t gfp_mask = readahead_gfp_mask(mapping);
+	bool use_list = mapping->a_ops->readpages;
 
 	if (isize == 0)
 		goto out;
@@ -170,7 +171,7 @@ unsigned long __do_page_cache_readahead(struct address_space *mapping,
 	 * Preallocate as many pages as we will need.
 	 */
 	for (page_idx = 0; page_idx < nr_to_read; page_idx++) {
-		pgoff_t page_offset = offset + page_idx;
+		page_offset = offset + page_idx;
 
 		if (page_offset > end_index)
 			break;
@@ -178,13 +179,14 @@ unsigned long __do_page_cache_readahead(struct address_space *mapping,
 		page = xa_load(&mapping->i_pages, page_offset);
 		if (page && !xa_is_value(page)) {
 			/*
-			 * Page already present?  Kick off the current batch of
-			 * contiguous pages before continuing with the next
-			 * batch.
+			 * Page already present?  Kick off the current batch
+			 * of contiguous pages before continuing with the
+			 * next batch.
 			 */
 			if (nr_pages)
-				read_pages(mapping, filp, &page_pool, nr_pages,
-						gfp_mask);
+				read_pages(mapping, filp, &page_pool,
+						page_offset - nr_pages,
+						nr_pages);
 			nr_pages = 0;
 			continue;
 		}
@@ -192,8 +194,18 @@ unsigned long __do_page_cache_readahead(struct address_space *mapping,
 		page = __page_cache_alloc(gfp_mask);
 		if (!page)
 			break;
-		page->index = page_offset;
-		list_add(&page->lru, &page_pool);
+		if (use_list) {
+			page->index = page_offset;
+			list_add(&page->lru, &page_pool);
+		} else if (!add_to_page_cache_lru(page, mapping, page_offset,
+					gfp_mask)) {
+			if (nr_pages)
+				read_pages(mapping, filp, &page_pool,
+						page_offset - nr_pages,
+						nr_pages);
+			nr_pages = 0;
+			continue;
+		}
 		if (page_idx == nr_to_read - lookahead_size)
 			SetPageReadahead(page);
 		nr_pages++;
@@ -205,7 +217,8 @@ unsigned long __do_page_cache_readahead(struct address_space *mapping,
 	 * will then handle the error.
 	 */
 	if (nr_pages)
-		read_pages(mapping, filp, &page_pool, nr_pages, gfp_mask);
+		read_pages(mapping, filp, &page_pool, page_offset - nr_pages,
+				nr_pages);
 	BUG_ON(!list_empty(&page_pool));
 out:
 	return nr_pages;
-- 
2.24.1


  parent reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-25  1:35 [PATCH 00/12] Change readahead API Matthew Wilcox
2020-01-25  1:35 ` [PATCH 01/12] mm: Fix the return type of __do_page_cache_readahead Matthew Wilcox
2020-01-25  1:35 ` [PATCH 02/12] readahead: Ignore return value of ->readpages Matthew Wilcox
2020-01-25  1:35 ` Matthew Wilcox [this message]
2020-01-25 19:44   ` [PATCH 03/12] readahead: Put pages in cache earlier Matthew Wilcox
2020-01-25  1:35 ` [PATCH 04/12] mm: Add readahead address space operation Matthew Wilcox
2020-01-25  3:57   ` Randy Dunlap
2020-02-01  0:25     ` Matthew Wilcox
2020-01-29  0:24   ` Dave Chinner
2020-01-30  8:00     ` Matthew Wilcox
2020-01-25  1:35 ` [PATCH 05/12] fs: Convert mpage_readpages to mpage_readahead Matthew Wilcox
2020-01-25  1:35 ` [PATCH 06/12] btrfs: Convert from readpages to readahead Matthew Wilcox
2020-01-29  0:46   ` Dave Chinner
2020-01-30  8:09     ` Matthew Wilcox
2020-01-31  2:17       ` Dave Chinner
2020-01-25  1:35 ` [PATCH 07/12] erofs: Convert uncompressed files " Matthew Wilcox
2020-01-25  1:53   ` Gao Xiang
2020-01-25 19:09     ` Matthew Wilcox
2020-01-29  0:57   ` Dave Chinner
2020-01-30  8:10     ` Matthew Wilcox
2020-01-25  1:35 ` [PATCH 08/12] erofs: Convert compressed " Matthew Wilcox
2020-01-25  1:35 ` [PATCH 09/12] ext4: Convert " Matthew Wilcox
2020-01-25  1:35 ` [PATCH 10/12] f2fs: " Matthew Wilcox
2020-01-25  1:35 ` [PATCH 11/12] fuse: " Matthew Wilcox
2020-01-29  1:08   ` Dave Chinner
2020-01-30 21:35     ` Matthew Wilcox
2020-01-31  2:19       ` Dave Chinner
2020-01-29 10:50   ` Miklos Szeredi
2020-01-30  7:26     ` Matthew Wilcox
2020-01-25  1:35 ` [PATCH 12/12] iomap: " Matthew Wilcox
2020-01-29  1:38   ` Dave Chinner
2020-01-31  9:44     ` Matthew Wilcox
2020-02-13  4:38 ` [PATCH 00/12] Change readahead API Andrew Morton
2020-02-13 13:43   ` Matthew Wilcox

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