From: Matthew Wilcox <willy@infradead.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
linux-fsdevel@vger.kernel.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,
Christoph Hellwig <hch@lst.de>,
William Kucharski <william.kucharski@oracle.com>
Subject: [PATCH v11 10/25] mm: Put readahead pages in cache earlier
Date: Tue, 14 Apr 2020 08:02:18 -0700 [thread overview]
Message-ID: <20200414150233.24495-11-willy@infradead.org> (raw)
In-Reply-To: <20200414150233.24495-1-willy@infradead.org>
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
When populating the page cache for readahead, mappings that use
->readpages must populate the page cache themselves as the pages are
passed on a linked list which would normally be used for the page cache's
LRU. For mappings that use ->readpage or the upcoming ->readahead method,
we can put the pages into the page cache as soon as they're allocated,
which solves a race between readahead and direct IO. It also lets us
remove the gfp argument from read_pages().
Use the new readahead_page() API to implement the repeated calls to
->readpage(), just like most filesystems will.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
---
mm/readahead.c | 46 ++++++++++++++++++++++++++++------------------
1 file changed, 28 insertions(+), 18 deletions(-)
diff --git a/mm/readahead.c b/mm/readahead.c
index ddc63d3b07b8..e52b3a7b9da5 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -114,14 +114,14 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages,
EXPORT_SYMBOL(read_cache_pages);
static void read_pages(struct readahead_control *rac, struct list_head *pages,
- gfp_t gfp)
+ bool skip_page)
{
const struct address_space_operations *aops = rac->mapping->a_ops;
+ struct page *page;
struct blk_plug plug;
- unsigned page_idx;
if (!readahead_count(rac))
- return;
+ goto out;
blk_start_plug(&plug);
@@ -130,23 +130,23 @@ static void read_pages(struct readahead_control *rac, struct list_head *pages,
readahead_count(rac));
/* Clean up the remaining pages */
put_pages_list(pages);
- goto out;
- }
-
- for (page_idx = 0; page_idx < readahead_count(rac); page_idx++) {
- struct page *page = lru_to_page(pages);
- list_del(&page->lru);
- if (!add_to_page_cache_lru(page, rac->mapping, page->index,
- gfp))
+ rac->_index += rac->_nr_pages;
+ rac->_nr_pages = 0;
+ } else {
+ while ((page = readahead_page(rac))) {
aops->readpage(rac->file, page);
- put_page(page);
+ put_page(page);
+ }
}
-out:
blk_finish_plug(&plug);
BUG_ON(!list_empty(pages));
- rac->_nr_pages = 0;
+ BUG_ON(readahead_count(rac));
+
+out:
+ if (skip_page)
+ rac->_index++;
}
/*
@@ -168,6 +168,7 @@ void __do_page_cache_readahead(struct address_space *mapping,
struct readahead_control rac = {
.mapping = mapping,
.file = filp,
+ ._index = index,
};
unsigned long i;
@@ -183,6 +184,8 @@ void __do_page_cache_readahead(struct address_space *mapping,
if (index + i > end_index)
break;
+ BUG_ON(index + i != rac._index + rac._nr_pages);
+
page = xa_load(&mapping->i_pages, index + i);
if (page && !xa_is_value(page)) {
/*
@@ -190,15 +193,22 @@ void __do_page_cache_readahead(struct address_space *mapping,
* contiguous pages before continuing with the next
* batch.
*/
- read_pages(&rac, &page_pool, gfp_mask);
+ read_pages(&rac, &page_pool, true);
continue;
}
page = __page_cache_alloc(gfp_mask);
if (!page)
break;
- page->index = index + i;
- list_add(&page->lru, &page_pool);
+ if (mapping->a_ops->readpages) {
+ page->index = index + i;
+ list_add(&page->lru, &page_pool);
+ } else if (add_to_page_cache_lru(page, mapping, index + i,
+ gfp_mask) < 0) {
+ put_page(page);
+ read_pages(&rac, &page_pool, true);
+ continue;
+ }
if (i == nr_to_read - lookahead_size)
SetPageReadahead(page);
rac._nr_pages++;
@@ -209,7 +219,7 @@ void __do_page_cache_readahead(struct address_space *mapping,
* uptodate then the caller will launch readpage again, and
* will then handle the error.
*/
- read_pages(&rac, &page_pool, gfp_mask);
+ read_pages(&rac, &page_pool, false);
}
/*
--
2.25.1
next prev parent reply other threads:[~2020-04-14 15:21 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-14 15:02 [PATCH v11 00/25] Change readahead API Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 01/25] mm: Move readahead prototypes from mm.h Matthew Wilcox
2020-04-15 9:10 ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 02/25] mm: Return void from various readahead functions Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 03/25] mm: Ignore return value of ->readpages Matthew Wilcox
2020-04-15 9:17 ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 04/25] mm: Move readahead nr_pages check into read_pages Matthew Wilcox
2020-04-15 9:19 ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 05/25] mm: Add new readahead_control API Matthew Wilcox
2020-04-15 1:17 ` Andrew Morton
2020-04-15 2:18 ` Matthew Wilcox
2020-04-15 4:56 ` Andrew Morton
2020-04-15 11:22 ` Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 06/25] mm: Use readahead_control to pass arguments Matthew Wilcox
2020-04-15 9:30 ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 07/25] mm: Rename various 'offset' parameters to 'index' Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 08/25] mm: rename readahead loop variable to 'i' Matthew Wilcox
2020-04-15 9:31 ` Johannes Thumshirn
2020-04-14 15:02 ` [PATCH v11 09/25] mm: Remove 'page_offset' from readahead loop Matthew Wilcox
2020-04-14 15:02 ` Matthew Wilcox [this message]
2020-04-14 15:02 ` [PATCH v11 11/25] mm: Add readahead address space operation Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 12/25] mm: Move end_index check out of readahead loop Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 13/25] mm: Add page_cache_readahead_unbounded Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 14/25] mm: Document why we don't set PageReadahead Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 15/25] mm: Use memalloc_nofs_save in readahead path Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 16/25] fs: Convert mpage_readpages to mpage_readahead Matthew Wilcox
2020-06-16 22:36 ` [Cluster-devel] " Andreas Gruenbacher
2020-06-17 0:32 ` Matthew Wilcox
2020-06-17 0:57 ` Andreas Grünbacher
2020-06-17 2:21 ` Matthew Wilcox
2020-06-18 12:46 ` Andreas Gruenbacher
2020-06-18 15:03 ` Matthew Wilcox
2020-06-18 16:40 ` Andreas Gruenbacher
2020-04-14 15:02 ` [PATCH v11 17/25] btrfs: Convert from readpages to readahead Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 18/25] erofs: Convert uncompressed files " Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 19/25] erofs: Convert compressed " Matthew Wilcox
2020-04-21 5:42 ` Andrew Morton
2020-04-21 7:28 ` Gao Xiang
2020-04-14 15:02 ` [PATCH v11 20/25] ext4: Convert " Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 21/25] ext4: Pass the inode to ext4_mpage_readpages Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 22/25] f2fs: Convert from readpages to readahead Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 23/25] f2fs: Pass the inode to f2fs_mpage_readpages Matthew Wilcox
2020-04-14 15:02 ` [PATCH v11 24/25] fuse: Convert from readpages to readahead Matthew Wilcox
2020-04-20 11:14 ` Miklos Szeredi
2020-04-20 11:43 ` Matthew Wilcox
2020-04-20 11:54 ` Miklos Szeredi
2020-04-14 15:02 ` [PATCH v11 25/25] iomap: " Matthew Wilcox
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