Linux-Fsdevel Archive on lore.kernel.org
 help / color / Atom feed
From: Dave Chinner <david@fromorbit.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 06/12] btrfs: Convert from readpages to readahead
Date: Wed, 29 Jan 2020 11:46:09 +1100
Message-ID: <20200129004609.GI18610@dread.disaster.area> (raw)
In-Reply-To: <20200125013553.24899-7-willy@infradead.org>

On Fri, Jan 24, 2020 at 05:35:47PM -0800, Matthew Wilcox wrote:
> From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> 
> Use the new readahead operation in btrfs
> 
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> Cc: linux-btrfs@vger.kernel.org
> ---
>  fs/btrfs/extent_io.c | 15 ++++-----------
>  fs/btrfs/extent_io.h |  2 +-
>  fs/btrfs/inode.c     | 18 +++++++++---------
>  3 files changed, 14 insertions(+), 21 deletions(-)
> 
> diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
> index 2f4802f405a2..b1e2acbec165 100644
> --- a/fs/btrfs/extent_io.c
> +++ b/fs/btrfs/extent_io.c
> @@ -4283,7 +4283,7 @@ int extent_writepages(struct address_space *mapping,
>  	return ret;
>  }
>  
> -int extent_readpages(struct address_space *mapping, struct list_head *pages,
> +unsigned extent_readahead(struct address_space *mapping, pgoff_t start,
>  		     unsigned nr_pages)
>  {
>  	struct bio *bio = NULL;
> @@ -4294,20 +4294,13 @@ int extent_readpages(struct address_space *mapping, struct list_head *pages,
>  	int nr = 0;
>  	u64 prev_em_start = (u64)-1;
>  
> -	while (!list_empty(pages)) {
> +	while (nr_pages) {
>  		u64 contig_end = 0;
>  
> -		for (nr = 0; nr < ARRAY_SIZE(pagepool) && !list_empty(pages);) {
> -			struct page *page = lru_to_page(pages);
> +		for (nr = 0; nr < ARRAY_SIZE(pagepool) && nr_pages--;) {

What is stopping nr_pages from going negative here, and then looping
forever on the outer nr_pages loop? Perhaps "while(nr_pages > 0) {"
would be better there?

-Dave.
-- 
Dave Chinner
david@fromorbit.com

  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 ` [PATCH 03/12] readahead: Put pages in cache earlier Matthew Wilcox
2020-01-25 19:44   ` 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 [this message]
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

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=20200129004609.GI18610@dread.disaster.area \
    --to=david@fromorbit.com \
    --cc=linux-btrfs@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=willy@infradead.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

Linux-Fsdevel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-fsdevel/0 linux-fsdevel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-fsdevel linux-fsdevel/ https://lore.kernel.org/linux-fsdevel \
		linux-fsdevel@vger.kernel.org
	public-inbox-index linux-fsdevel

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-fsdevel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git