From: Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
andi-Vw/NltI1exuRpAAqCnN02g@public.gmane.org,
oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org,
viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org,
davidel-AhlLAIvw+VEjIGhXcJzhZg@public.gmane.org,
davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org,
hch-jcswGhMUV9g@public.gmane.org,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
mpm-VDJrAJ4Gl5ZBDgjK7y7TUQ@public.gmane.org,
alan-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org,
corbet-T1hC0tSOHrs@public.gmane.org
Subject: Re: [PATCH 2/4] Convert epoll to a bitlock
Date: Tue, 3 Feb 2009 13:39:42 -0800 [thread overview]
Message-ID: <20090203133942.2ecec281.akpm@linux-foundation.org> (raw)
In-Reply-To: <1233598811-6871-3-git-send-email-corbet-T1hC0tSOHrs@public.gmane.org>
On Mon, 2 Feb 2009 11:20:09 -0700
Jonathan Corbet <corbet-T1hC0tSOHrs@public.gmane.org> 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.
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WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Jonathan Corbet <corbet@lwn.net>
Cc: 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, corbet@lwn.net
Subject: Re: [PATCH 2/4] Convert epoll to a bitlock
Date: Tue, 3 Feb 2009 13:39:42 -0800 [thread overview]
Message-ID: <20090203133942.2ecec281.akpm@linux-foundation.org> (raw)
In-Reply-To: <1233598811-6871-3-git-send-email-corbet@lwn.net>
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.
next prev parent reply other threads:[~2009-02-03 21:39 UTC|newest]
Thread overview: 46+ 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 ` Jonathan Corbet
[not found] ` <1233598811-6871-1-git-send-email-corbet-T1hC0tSOHrs@public.gmane.org>
2009-02-02 18:20 ` [PATCH 1/4] Use bit operations for file->f_flags Jonathan Corbet
2009-02-02 18:20 ` Jonathan Corbet
[not found] ` <1233598811-6871-2-git-send-email-corbet-T1hC0tSOHrs@public.gmane.org>
2009-02-03 21:37 ` Andrew Morton
2009-02-03 21:37 ` Andrew Morton
2009-02-02 18:20 ` [PATCH 2/4] Convert epoll to a bitlock Jonathan Corbet
2009-02-02 18:20 ` Jonathan Corbet
[not found] ` <1233598811-6871-3-git-send-email-corbet-T1hC0tSOHrs@public.gmane.org>
2009-02-03 21:39 ` Andrew Morton [this message]
2009-02-03 21:39 ` Andrew Morton
[not found] ` <20090203133942.2ecec281.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2009-02-03 21:55 ` Eric Dumazet
2009-02-03 21:55 ` Eric Dumazet
[not found] ` <4988BD4E.8080206-fPLkHRcR87vqlBn2x/YWAg@public.gmane.org>
2009-02-03 22:05 ` Andrew Morton
2009-02-03 22:05 ` Andrew Morton
[not found] ` <20090203140543.6e915f97.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2009-02-03 22:22 ` Matt Mackall
2009-02-03 22:22 ` Matt Mackall
2009-02-03 22:37 ` Jonathan Corbet
2009-02-03 22:37 ` Jonathan Corbet
[not found] ` <20090203153740.363d0a04-vw3g6Xz/EtPk1uMJSBkQmQ@public.gmane.org>
2009-02-03 22:53 ` Andrew Morton
2009-02-03 22:53 ` Andrew Morton
[not found] ` <20090203145346.8df40277.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2009-02-03 23:09 ` Davide Libenzi
2009-02-03 23:09 ` Davide Libenzi
[not found] ` <alpine.DEB.1.10.0902031508280.23050-GPJ85BhbkB8RepQJljzAVbITYcZ0+W3JAL8bYrjMMd8@public.gmane.org>
2009-02-03 23:12 ` Davide Libenzi
2009-02-03 23:12 ` Davide Libenzi
2009-02-03 23:19 ` Jonathan Corbet
2009-02-03 23:19 ` Jonathan Corbet
[not found] ` <20090203161931.4054a25e-vw3g6Xz/EtPk1uMJSBkQmQ@public.gmane.org>
2009-02-03 23:29 ` Andrew Morton
2009-02-03 23:29 ` Andrew Morton
2009-02-04 7:13 ` Christoph Hellwig
2009-02-04 7:13 ` Christoph Hellwig
[not found] ` <20090204071320.GA19348-jcswGhMUV9g@public.gmane.org>
2009-02-04 7:20 ` Nick Piggin
2009-02-04 7:20 ` Nick Piggin
[not found] ` <200902041820.20535.nickpiggin-/E1597aS9LT0CCvOHzKKcA@public.gmane.org>
2009-02-04 13:34 ` Jonathan Corbet
2009-02-04 13:34 ` Jonathan Corbet
2009-02-04 16:51 ` Davide Libenzi
2009-02-04 16:51 ` Davide Libenzi
2009-02-03 23:08 ` Davide Libenzi
2009-02-03 23:08 ` Davide Libenzi
[not found] ` <alpine.DEB.1.10.0902031446280.23050-GPJ85BhbkB8RepQJljzAVbITYcZ0+W3JAL8bYrjMMd8@public.gmane.org>
2009-02-04 2:48 ` Eric Dumazet
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 ` Jonathan Corbet
2009-02-02 18:20 ` [PATCH 4/4] Rationalize fasync return values Jonathan Corbet
2009-02-02 18:20 ` Jonathan Corbet
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