From: Christoph Hellwig <hch@lst.de>
To: linux-xfs@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: [PATCH 04/13] mm: split ->readpages calls to avoid non-contiguous pages lists
Date: Thu, 31 May 2018 20:06:05 +0200 [thread overview]
Message-ID: <20180531180614.21506-5-hch@lst.de> (raw)
In-Reply-To: <20180531180614.21506-1-hch@lst.de>
That way file systems don't have to go spotting for non-contiguous pages
and work around them. It also kicks off I/O earlier, allowing it to
finish earlier and reduce latency.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
---
mm/readahead.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/mm/readahead.c b/mm/readahead.c
index fa4d4b767130..e273f0de3376 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -140,8 +140,8 @@ static int read_pages(struct address_space *mapping, struct file *filp,
}
/*
- * __do_page_cache_readahead() actually reads a chunk of disk. It allocates all
- * the pages first, then submits them all for I/O. This avoids the very bad
+ * __do_page_cache_readahead() actually reads a chunk of disk. It allocates
+ * the pages first, then submits them for I/O. This avoids the very bad
* behaviour which would occur if page allocations are causing VM writeback.
* We really don't want to intermingle reads and writes like that.
*
@@ -177,8 +177,18 @@ unsigned int __do_page_cache_readahead(struct address_space *mapping,
rcu_read_lock();
page = radix_tree_lookup(&mapping->i_pages, page_offset);
rcu_read_unlock();
- if (page && !radix_tree_exceptional_entry(page))
+ if (page && !radix_tree_exceptional_entry(page)) {
+ /*
+ * 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);
+ nr_pages = 0;
continue;
+ }
page = __page_cache_alloc(gfp_mask);
if (!page)
--
2.17.0
next prev parent reply other threads:[~2018-05-31 18:06 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-31 18:06 iomap based buffered reads & iomap cleanups v5 Christoph Hellwig
2018-05-31 18:06 ` [PATCH 01/13] block: add a lower-level bio_add_page interface Christoph Hellwig
2018-05-31 18:06 ` [PATCH 02/13] mm: give the 'ret' variable a better name __do_page_cache_readahead Christoph Hellwig
2018-05-31 18:06 ` [PATCH 03/13] mm: return an unsigned int from __do_page_cache_readahead Christoph Hellwig
2018-05-31 18:06 ` Christoph Hellwig [this message]
2018-05-31 18:06 ` [PATCH 05/13] iomap: inline data should be an iomap type, not a flag Christoph Hellwig
2018-05-31 18:06 ` [PATCH 06/13] iomap: fix the comment describing IOMAP_NOWAIT Christoph Hellwig
2018-05-31 18:06 ` [PATCH 07/13] iomap: move IOMAP_F_BOUNDARY to gfs2 Christoph Hellwig
2018-05-31 18:06 ` [PATCH 08/13] iomap: use __bio_add_page in iomap_dio_zero Christoph Hellwig
2018-05-31 18:06 ` [PATCH 09/13] iomap: add a iomap_sector helper Christoph Hellwig
2018-05-31 18:06 ` [PATCH 10/13] iomap: add an iomap-based bmap implementation Christoph Hellwig
2018-05-31 18:06 ` [PATCH 11/13] iomap: add an iomap-based readpage and readpages implementation Christoph Hellwig
2018-05-31 18:06 ` [PATCH 12/13] xfs: use iomap_bmap Christoph Hellwig
2018-05-31 18:06 ` [PATCH 13/13] xfs: use iomap for blocksize == PAGE_SIZE readpage and readpages Christoph Hellwig
-- strict thread matches above, loose matches on Subject: below --
2018-05-30 9:58 iomap based buffered reads & iomap cleanups v4 Christoph Hellwig
2018-05-30 9:58 ` [PATCH 04/13] mm: split ->readpages calls to avoid non-contiguous pages lists Christoph Hellwig
2018-05-30 23:02 ` Dave Chinner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180531180614.21506-5-hch@lst.de \
--to=hch@lst.de \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-xfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).