From: "H. Peter Anvin" <hpa@zytor.com>
To: Satyam Sharma <satyam.sharma@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
Johannes Stezenbach <js@linuxtv.org>,
Jesper Juhl <jesper.juhl@gmail.com>,
Randy Dunlap <randy.dunlap@oracle.com>,
Heikki Orsila <shdl@zakalwe.fi>,
jimmy bahuleyan <knight.camelot@gmail.com>,
Stefan Richter <stefanr@s5r6.in-berlin.de>
Subject: Re: [PATCH] "volatile considered harmful", take 3
Date: Fri, 11 May 2007 22:41:40 -0700 [thread overview]
Message-ID: <46455394.6020302@zytor.com> (raw)
In-Reply-To: <464551D5.2050709@zytor.com>
H. Peter Anvin wrote:
>
> I don't see why Alan's way is necessarily better; it should work but is
> more heavy-handed as it's disabling *all* optimization such as loop
> invariants across the barrier.
>
To expand on this further: the way this probably *should* be handled,
Linux-style, is with internally-volatile versions of le32_to_cpup() and
friends. That obeys the concept that the volatility should be
associated with an operation, not a data structure, and, being related
to an I/O device, should have its endianness explicitly declared.
Right now those macros don't exist, however.
-hpa
next prev parent reply other threads:[~2007-05-12 5:42 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-11 17:36 [PATCH] "volatile considered harmful", take 3 Jonathan Corbet
2007-05-11 21:25 ` Jesper Juhl
2007-05-12 3:21 ` Satyam Sharma
2007-05-12 4:29 ` Jeff Garzik
2007-05-12 5:34 ` H. Peter Anvin
2007-05-12 5:41 ` H. Peter Anvin [this message]
2007-05-12 6:15 ` Satyam Sharma
2007-05-12 6:21 ` H. Peter Anvin
2007-05-12 7:02 ` Satyam Sharma
2007-05-12 7:13 ` H. Peter Anvin
2007-05-12 7:28 ` Satyam Sharma
2007-05-12 7:53 ` Stefan Richter
2007-05-12 11:51 ` Heikki Orsila
2007-05-12 18:06 ` H. Peter Anvin
2007-05-12 7:22 ` Stefan Richter
2007-05-12 7:33 ` jimmy bahuleyan
2007-05-12 7:45 ` Jeff Garzik
2007-05-12 19:17 ` Dr. David Alan Gilbert
[not found] <8jHg3-1T2-5@gated-at.bofh.it>
[not found] ` <8jQt5-7As-3@gated-at.bofh.it>
[not found] ` <8jSuQ-28J-21@gated-at.bofh.it>
[not found] ` <8jT7y-39x-9@gated-at.bofh.it>
2007-05-13 0:00 ` Bodo Eggert
2007-05-14 3:37 ` Satyam Sharma
2007-05-17 23:51 ` Bill Davidsen
2007-05-18 3:13 ` Satyam Sharma
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