From: Johannes Weiner <hannes@cmpxchg.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, Rik van Riel <riel@redhat.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Mel Gorman <mgorman@suse.de>, Minchan Kim <minchan.kim@gmail.com>,
Hugh Dickins <hughd@google.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [patch 2/5] mm + fs: prepare for non-page entries in page cache
Date: Tue, 1 May 2012 22:15:04 +0200 [thread overview]
Message-ID: <20120501201504.GB2112@cmpxchg.org> (raw)
In-Reply-To: <20120501120246.83d2ce28.akpm@linux-foundation.org>
On Tue, May 01, 2012 at 12:02:46PM -0700, Andrew Morton wrote:
> On Tue, 1 May 2012 10:41:50 +0200
> Johannes Weiner <hannes@cmpxchg.org> wrote:
>
> > --- a/fs/inode.c
> > +++ b/fs/inode.c
> > @@ -544,8 +544,7 @@ static void evict(struct inode *inode)
> > if (op->evict_inode) {
> > op->evict_inode(inode);
> > } else {
> > - if (inode->i_data.nrpages)
> > - truncate_inode_pages(&inode->i_data, 0);
> > + truncate_inode_pages(&inode->i_data, 0);
>
> Why did we lose this optimisation?
For inodes with only shadow pages remaining in the tree, because there
is no separate counter for them. Otherwise, we'd leak the tree nodes.
I had mapping->nrshadows at first to keep truncation conditional, but
thought that using an extra word per cached inode would be worse than
removing this optimization. There is not too much being done when the
tree is empty.
Another solution would be to include the shadows count in ->nrpages,
but filesystems use this counter for various other purposes.
Do you think it's worth reconsidering?
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next prev parent reply other threads:[~2012-05-01 20:15 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-01 8:41 [patch 0/5] refault distance-based file cache sizing Johannes Weiner
2012-05-01 8:41 ` [patch 1/5] mm: readahead: move radix tree hole searching here Johannes Weiner
2012-05-01 21:06 ` Rik van Riel
2012-05-01 8:41 ` [patch 2/5] mm + fs: prepare for non-page entries in page cache Johannes Weiner
2012-05-01 19:02 ` Andrew Morton
2012-05-01 20:15 ` Johannes Weiner [this message]
2012-05-01 20:24 ` Andrew Morton
2012-05-01 21:14 ` Rik van Riel
2012-05-01 21:29 ` Johannes Weiner
2012-05-01 8:41 ` [patch 3/5] mm + fs: store shadow pages " Johannes Weiner
2012-05-01 8:41 ` [patch 4/5] mm + fs: provide refault distance to page cache instantiations Johannes Weiner
2012-05-01 9:30 ` Peter Zijlstra
2012-05-01 9:55 ` Johannes Weiner
2012-05-01 9:58 ` Peter Zijlstra
2012-05-01 8:41 ` [patch 5/5] mm: refault distance-based file cache sizing Johannes Weiner
2012-05-01 14:13 ` Minchan Kim
2012-05-01 15:38 ` Johannes Weiner
2012-05-02 5:21 ` Minchan Kim
2012-05-02 1:57 ` Andrea Arcangeli
2012-05-02 6:23 ` Johannes Weiner
2012-05-02 15:11 ` Andrea Arcangeli
2012-05-01 19:08 ` [patch 0/5] " Andrew Morton
2012-05-01 21:19 ` Rik van Riel
2012-05-01 21:26 ` Andrew Morton
2012-05-02 1:10 ` Andrea Arcangeli
2012-05-03 13:15 ` Johannes Weiner
2012-05-16 5:25 ` nai.xia
2012-05-16 6:51 ` Johannes Weiner
2012-05-16 12:56 ` nai.xia
2012-05-17 21:08 ` Johannes Weiner
2012-05-18 3:44 ` Nai Xia
2012-05-18 15:07 ` Rik van Riel
2012-05-18 15:30 ` Nai Xia
2012-05-17 13:11 ` Rik van Riel
2012-05-18 5:03 ` Nai Xia
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