From: Eric Dumazet <dada1@cosmosbay.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonathan Corbet <corbet@lwn.net>,
linux-kernel@vger.kernel.org, andi@firstfloor.org,
oleg@redhat.com, viro@ZenIV.linux.org.uk,
davidel@xmailserver.org, davem@davemloft.net, hch@lst.de,
linux-api@vger.kernel.org, mpm@selenic.com,
alan@lxorguk.ukuu.org.uk
Subject: Re: [PATCH 2/4] Convert epoll to a bitlock
Date: Tue, 03 Feb 2009 22:55:26 +0100 [thread overview]
Message-ID: <4988BD4E.8080206@cosmosbay.com> (raw)
In-Reply-To: <20090203133942.2ecec281.akpm@linux-foundation.org>
Andrew Morton a écrit :
> On Mon, 2 Feb 2009 11:20:09 -0700
> Jonathan Corbet <corbet@lwn.net> wrote:
>
>> Matt Mackall suggested converting epoll's ep_lock to a bitlock as a way of
>> saving space in struct file. This patch makes that change.
>
> hrm. bit_spin_lock() makes people upset (large penguiny people). iirc
> it doesn't have all the correct/well-understood memory/compiler
> ordering semantics which spinlocks have. And lockdep doesn't know about
> it.
>
In a previous attempt (2005), I suggested using a single global lock.
http://search.luky.org/linux-kernel.2005/msg50862.html
Probably an array of hashed spinlocks would be more than enough.
next prev parent reply other threads:[~2009-02-03 22:16 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-02 18:20 [PATCH/RFC] F_SETFL/Fasync BKL removal, now without unsightly global locks Jonathan Corbet
2009-02-02 18:20 ` [PATCH 1/4] Use bit operations for file->f_flags Jonathan Corbet
2009-02-03 21:37 ` Andrew Morton
2009-02-02 18:20 ` [PATCH 2/4] Convert epoll to a bitlock Jonathan Corbet
2009-02-03 21:39 ` Andrew Morton
2009-02-03 21:55 ` Eric Dumazet [this message]
2009-02-03 22:05 ` Andrew Morton
2009-02-03 22:22 ` Matt Mackall
2009-02-03 22:37 ` Jonathan Corbet
2009-02-03 22:53 ` Andrew Morton
2009-02-03 23:09 ` Davide Libenzi
2009-02-03 23:12 ` Davide Libenzi
2009-02-03 23:19 ` Jonathan Corbet
2009-02-03 23:29 ` Andrew Morton
2009-02-04 7:13 ` Christoph Hellwig
2009-02-04 7:20 ` Nick Piggin
2009-02-04 13:34 ` Jonathan Corbet
2009-02-04 16:51 ` Davide Libenzi
2009-02-03 23:08 ` Davide Libenzi
2009-02-04 2:48 ` Eric Dumazet
2009-02-04 1:00 ` wli
2009-02-04 4:54 ` Nick Piggin
2009-02-02 18:20 ` [PATCH 3/4] Move FASYNC bit handling to f_op->fasync() Jonathan Corbet
2009-02-02 18:20 ` [PATCH 4/4] Rationalize fasync return values Jonathan Corbet
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=4988BD4E.8080206@cosmosbay.com \
--to=dada1@cosmosbay.com \
--cc=akpm@linux-foundation.org \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=andi@firstfloor.org \
--cc=corbet@lwn.net \
--cc=davem@davemloft.net \
--cc=davidel@xmailserver.org \
--cc=hch@lst.de \
--cc=linux-api@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mpm@selenic.com \
--cc=oleg@redhat.com \
--cc=viro@ZenIV.linux.org.uk \
/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