From: Matthew Wilcox <matthew@wil.cx>
To: Arnd Bergmann <arnd@arndb.de>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Ralf Baechle <ralf@linux-mips.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
Al Viro <viro@ftp.linux.org.uk>,
torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH 1/2] irq_flags_t: intro and core annotations
Date: Mon, 22 Oct 2007 13:47:14 -0600 [thread overview]
Message-ID: <20071022194714.GI27248@parisc-linux.org> (raw)
In-Reply-To: <200710222110.34768.arnd@arndb.de>
On Mon, Oct 22, 2007 at 09:10:34PM +0200, Arnd Bergmann wrote:
> On a related note, should we encourage the use of spin_lock() and
> spin_lock_irq() instead of spin_lock_irqsave() where possible?
spin_lock(), certainly. On PowerPC, I'm reliably informed it's fewer
instructions to save/restore than it is to disable/enable. So no clear
advantage there.
> On some architectures, accessing the interrupt flag is a heavyweight
> operation, especially when running under a hypervisor, so a number
> of drivers could benefit from being converted to not save the flags
> at all instead of just changing the type of the flags variable.
We certainly don't want to encourage people to blindly make those
conversions ... and I've seen the results of encouraging kernel janitors
to do things a certain way.
--
Intel are signing my paycheques ... these opinions are still mine
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
next prev parent reply other threads:[~2007-10-22 19:47 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-20 23:55 [PATCH 1/2] irq_flags_t: intro and core annotations Alexey Dobriyan
2007-10-21 0:54 ` Al Viro
2007-10-21 9:30 ` Alexey Dobriyan
2007-10-22 15:29 ` Ralf Baechle
2007-10-22 18:21 ` Andrew Morton
2007-10-22 18:50 ` Geert Uytterhoeven
2007-10-22 19:10 ` Arnd Bergmann
2007-10-22 19:47 ` Matthew Wilcox [this message]
2007-10-22 19:56 ` Linus Torvalds
2007-10-22 20:02 ` Andrew Morton
2007-10-22 21:34 ` Arnd Bergmann
2007-10-22 21:46 ` Thomas Gleixner
2007-10-23 1:06 ` Arnd Bergmann
2007-10-23 1:28 ` USB HCD: avoid duplicate local_irq_disable() Arnd Bergmann
2007-10-23 4:01 ` [linux-usb-devel] " Alan Stern
2007-10-25 18:33 ` Greg KH
2007-10-27 19:14 ` Alan Stern
2007-10-22 20:47 ` [PATCH 1/2] irq_flags_t: intro and core annotations Jeff Garzik
2007-10-23 0:21 ` David Miller
2007-10-23 3:33 ` Herbert Xu
2007-10-24 2:11 ` Jeff Garzik
2007-10-24 8:55 ` Arnd Bergmann
2007-10-27 19:20 ` Roman Zippel
2007-10-27 20:14 ` Alexey Dobriyan
2007-10-27 21:07 ` Peter Zijlstra
2007-10-27 21:22 ` Roman Zippel
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=20071022194714.GI27248@parisc-linux.org \
--to=matthew@wil.cx \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=arnd@arndb.de \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ralf@linux-mips.org \
--cc=torvalds@linux-foundation.org \
--cc=viro@ftp.linux.org.uk \
--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;
as well as URLs for NNTP newsgroup(s).