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, cluster-devel@redhat.com,
ocfs2-devel@oss.oracle.com, linux-xfs@vger.kernel.org
Subject: [PATCH v5 03/13] mm: Put readahead pages in cache earlier
Date: Mon, 10 Feb 2020 17:03:38 -0800 [thread overview]
Message-ID: <20200211010348.6872-4-willy@infradead.org> (raw)
In-Reply-To: <20200211010348.6872-1-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>
---
mm/readahead.c | 66 ++++++++++++++++++++++++++++++++------------------
1 file changed, 42 insertions(+), 24 deletions(-)
diff --git a/mm/readahead.c b/mm/readahead.c
index fc77d13af556..96c6ca68a174 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);
}
@@ -149,17 +148,18 @@ static void read_pages(struct address_space *mapping, struct file *filp,
* Returns the number of pages requested, or the maximum amount of I/O allowed.
*/
unsigned long __do_page_cache_readahead(struct address_space *mapping,
- struct file *filp, pgoff_t offset, unsigned long nr_to_read,
+ struct file *filp, pgoff_t start, unsigned long nr_to_read,
unsigned long lookahead_size)
{
struct inode *inode = mapping->host;
- struct page *page;
unsigned long end_index; /* The last page we want to read */
LIST_HEAD(page_pool);
int page_idx;
+ pgoff_t page_offset = start;
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 +170,7 @@ 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;
+ struct page *page;
if (page_offset > end_index)
break;
@@ -178,25 +178,43 @@ 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.
+ * It's possible this page is the page we should
+ * be marking with PageReadahead. However, we
+ * don't have a stable ref to this page so it might
+ * be reallocated to another user before we can set
+ * the bit. There's probably another page in the
+ * cache marked with PageReadahead from the other
+ * process which accessed this file.
*/
- if (nr_pages)
- read_pages(mapping, filp, &page_pool, nr_pages,
- gfp_mask);
- nr_pages = 0;
- continue;
+ goto skip;
}
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) < 0) {
+ put_page(page);
+ goto skip;
+ }
+
if (page_idx == nr_to_read - lookahead_size)
SetPageReadahead(page);
nr_pages++;
+ page_offset++;
+ continue;
+skip:
+ if (nr_pages)
+ read_pages(mapping, filp, &page_pool, start, nr_pages);
+ nr_pages = 0;
+ page_offset++;
+ start = page_offset;
}
/*
@@ -205,7 +223,7 @@ 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, start, nr_pages);
BUG_ON(!list_empty(&page_pool));
out:
return nr_pages;
--
2.25.0
next prev parent reply other threads:[~2020-02-11 1:04 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 1:03 [PATCH v5 00/13] Change readahead API Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 01/13] mm: Fix the return type of __do_page_cache_readahead Matthew Wilcox
2020-02-11 8:19 ` Johannes Thumshirn
2020-02-11 12:34 ` Matthew Wilcox
2020-02-12 18:13 ` Christoph Hellwig
2020-02-14 3:19 ` John Hubbard
2020-02-14 4:21 ` Matthew Wilcox
2020-02-14 4:33 ` John Hubbard
2020-02-14 19:50 ` Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 02/13] mm: Ignore return value of ->readpages Matthew Wilcox
2020-02-12 18:13 ` Christoph Hellwig
2020-02-11 1:03 ` Matthew Wilcox [this message]
2020-02-14 3:36 ` [PATCH v5 03/13] mm: Put readahead pages in cache earlier John Hubbard
2020-02-15 1:15 ` Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 04/13] mm: Add readahead address space operation Matthew Wilcox
2020-02-11 4:52 ` Dave Chinner
2020-02-11 12:54 ` Matthew Wilcox
2020-02-11 20:08 ` Dave Chinner
2020-02-12 18:18 ` Christoph Hellwig
2020-02-14 5:36 ` John Hubbard
2020-02-15 1:15 ` Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 05/13] mm: Add page_cache_readahead_limit Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 06/13] fs: Convert mpage_readpages to mpage_readahead Matthew Wilcox
2020-02-13 22:09 ` Junxiao Bi
2020-02-11 1:03 ` [PATCH v5 07/13] btrfs: Convert from readpages to readahead Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 08/13] erofs: Convert uncompressed files " Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 09/13] erofs: Convert compressed " Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 10/13] ext4: Convert " Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 11/13] f2fs: " Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 12/13] fuse: " Matthew Wilcox
2020-02-11 1:03 ` [PATCH v5 13/13] iomap: " Matthew Wilcox
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