From: Matthew Wilcox <willy@infradead.org>
To: Eric Biggers <ebiggers@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-xfs@vger.kernel.org,
William Kucharski <william.kucharski@oracle.com>,
linux-kernel@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com,
linux-mm@kvack.org, ocfs2-devel@oss.oracle.com,
linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org,
linux-erofs@lists.ozlabs.org, linux-btrfs@vger.kernel.org
Subject: Re: [PATCH v9 20/25] ext4: Convert from readpages to readahead
Date: Fri, 20 Mar 2020 10:48:48 -0700 [thread overview]
Message-ID: <20200320174848.GC4971@bombadil.infradead.org> (raw)
In-Reply-To: <20200320173734.GD851@sol.localdomain>
On Fri, Mar 20, 2020 at 10:37:34AM -0700, Eric Biggers wrote:
> On Fri, Mar 20, 2020 at 07:22:26AM -0700, Matthew Wilcox wrote:
> > From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
> >
> > Use the new readahead operation in ext4
> >
> > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> > Reviewed-by: William Kucharski <william.kucharski@oracle.com>
> > ---
> > fs/ext4/ext4.h | 3 +--
> > fs/ext4/inode.c | 21 +++++++++------------
> > fs/ext4/readpage.c | 22 ++++++++--------------
> > 3 files changed, 18 insertions(+), 28 deletions(-)
> >
>
> Reviewed-by: Eric Biggers <ebiggers@google.com>
>
> > + if (rac) {
> > + page = readahead_page(rac);
> > prefetchw(&page->flags);
> > - list_del(&page->lru);
> > - if (add_to_page_cache_lru(page, mapping, page->index,
> > - readahead_gfp_mask(mapping)))
> > - goto next_page;
> > }
>
> Maybe the prefetchw(&page->flags) should be included in readahead_page()?
> Most of the callers do it.
I did notice that a lot of callers do that. I wonder whether it (still)
helps or whether it's just cargo-cult programming. It can't possibly
have helped before because we did list_del(&page->lru) as the very next
instruction after prefetchw(), and they're in the same cacheline. It'd
be interesting to take it out and see what happens to performance.
next prev parent reply other threads:[~2020-03-20 17:48 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-20 14:22 [PATCH v9 00/25] Change readahead API Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 01/25] mm: Move readahead prototypes from mm.h Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 02/25] mm: Return void from various readahead functions Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 03/25] mm: Ignore return value of ->readpages Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 04/25] mm: Move readahead nr_pages check into read_pages Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 05/25] mm: Add new readahead_control API Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 06/25] mm: Use readahead_control to pass arguments Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 07/25] mm: Rename various 'offset' parameters to 'index' Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 08/25] mm: rename readahead loop variable to 'i' Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 09/25] mm: Remove 'page_offset' from readahead loop Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 10/25] mm: Put readahead pages in cache earlier Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 11/25] mm: Add readahead address space operation Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 12/25] mm: Move end_index check out of readahead loop Matthew Wilcox
2020-03-20 16:58 ` Eric Biggers
2020-03-20 17:30 ` Matthew Wilcox
2020-03-20 18:00 ` Eric Biggers
2020-03-20 18:11 ` Matthew Wilcox
2020-03-20 18:24 ` Eric Biggers
2020-03-22 16:28 ` Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 13/25] mm: Add page_cache_readahead_unbounded Matthew Wilcox
2020-03-20 17:27 ` Eric Biggers
2020-03-20 14:22 ` [PATCH v9 14/25] mm: Document why we don't set PageReadahead Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 15/25] mm: Use memalloc_nofs_save in readahead path Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 16/25] fs: Convert mpage_readpages to mpage_readahead Matthew Wilcox
2020-03-20 23:24 ` Namjae Jeon
2020-03-20 14:22 ` [PATCH v9 17/25] btrfs: Convert from readpages to readahead Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 18/25] erofs: Convert uncompressed files " Matthew Wilcox
2020-03-21 12:38 ` [f2fs-dev] " Chao Yu
2020-03-20 14:22 ` [PATCH v9 19/25] erofs: Convert compressed " Matthew Wilcox
2020-03-21 12:41 ` [f2fs-dev] " Chao Yu
2020-03-20 14:22 ` [PATCH v9 20/25] ext4: Convert " Matthew Wilcox
2020-03-20 17:37 ` Eric Biggers
2020-03-20 17:48 ` Matthew Wilcox [this message]
2020-03-20 18:40 ` Eric Biggers
2020-03-20 14:22 ` [PATCH v9 21/25] ext4: Pass the inode to ext4_mpage_readpages Matthew Wilcox
2020-03-20 18:44 ` Eric Biggers
2020-03-20 14:22 ` [PATCH v9 22/25] f2fs: Convert from readpages to readahead Matthew Wilcox
2020-03-20 18:51 ` Eric Biggers
2020-03-21 12:34 ` [f2fs-dev] " Chao Yu
2020-03-23 3:55 ` Jaegeuk Kim
2020-03-20 14:22 ` [PATCH v9 23/25] f2fs: Pass the inode to f2fs_mpage_readpages Matthew Wilcox
2020-03-20 18:52 ` Eric Biggers
2020-03-21 12:35 ` [f2fs-dev] " Chao Yu
2020-03-23 3:53 ` Jaegeuk Kim
2020-03-20 14:22 ` [PATCH v9 24/25] fuse: Convert from readpages to readahead Matthew Wilcox
2020-03-20 14:22 ` [PATCH v9 25/25] iomap: " Matthew Wilcox
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