linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Matthew Wilcox <willy@infradead.org>
To: Wei Yang <richard.weiyang@gmail.com>
Cc: "Tobin C. Harding" <tobin@kernel.org>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] xarray: Document erasing entries during iteration
Date: Wed, 13 Feb 2019 08:12:58 -0800	[thread overview]
Message-ID: <20190213161258.GS12668@bombadil.infradead.org> (raw)
In-Reply-To: <20190213144744.ifejzbxrbaltivwc@master>

On Wed, Feb 13, 2019 at 02:47:44PM +0000, Wei Yang wrote:
> On Tue, Feb 12, 2019 at 05:51:29AM -0800, Matthew Wilcox wrote:
> >That is _fine_.  As you know I hope to get rid of the radix tree soon ;-)
> 
> You mean replace radix tree in whole kernel? That would be a big effort.

Already mostly done.

http://git.infradead.org/users/willy/linux-dax.git/shortlog/refs/heads/xarray-conv

The only remaining user of the radix tree in that tree is the IDR.  So
now I'm converting the IDR users over to the XArray as well.


But that isn't what I was talking about.  At the moment, the radix
tree and the XArray use the same data structure.  It has good best-case
performance, but shockingly bad worst-case performance.  So we're looking
at replacing the data structure, which won't require changing any of the
users (maybe the page cache ... that has some pretty intimate knowledge
of exactly how the radix tree works).

> BTW, have we compared the performance difference?

It's in the noise.  Sometimes the XArray does a little better because
the APIs encourage the user to do things in a more efficient way.
Some of the users are improved just because the original author didn't
know about a more efficient way of doing what they wanted to do.



  reply	other threads:[~2019-02-13 16:13 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-12  7:29 [PATCH] xarray: Document erasing entries during iteration Tobin C. Harding
2019-02-12 13:51 ` Matthew Wilcox
2019-02-13 14:47   ` Wei Yang
2019-02-13 16:12     ` Matthew Wilcox [this message]
2019-02-14 22:16       ` Wei Yang
2019-02-14 22:33         ` Matthew Wilcox
2019-02-16 21:53           ` Wei Yang
2019-02-13  1:13 ` Tobin C. Harding

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=20190213161258.GS12668@bombadil.infradead.org \
    --to=willy@infradead.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=richard.weiyang@gmail.com \
    --cc=tobin@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).