From: David Howells <dhowells@redhat.com>
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: dhowells@redhat.com,
Linus Torvalds <torvalds@linux-foundation.org>,
Hirokazu Takata <takata@linux-m32r.org>,
"Robert P. J. Day" <rpjday@mindspring.com>,
paulmck@linux.vnet.ibm.com, linux-kernel@vger.kernel.org, "Luck,
Tony" <tony.luck@intel.com>,
akpm@linux-foundation.org, linux-arch@vger.kernel.org,
Chris Snook <csnook@redhat.com>,
Chris Friesen <cfriesen@nortel.com>
Subject: Re: [PATCH 11/23] make atomic_read() and atomic_set() behavior consistent on m32r
Date: Thu, 23 Aug 2007 21:05:40 +0100 [thread overview]
Message-ID: <14578.1187899540@redhat.com> (raw)
In-Reply-To: <e8b5ee6194ed619c245eb884c5ae6b11@kernel.crashing.org>
Segher Boessenkool <segher@kernel.crashing.org> wrote:
> This simply isn't true. The compiler *can* combine asm stuff:
>
>
> typedef struct { int counter; } atomic_t;
>
> static inline __attribute__((pure)) int atomic_read(const atomic_t *v)
> {
> int x;
> asm("ld %0,@%1" : "=r"(x) : "r"(&v->counter), "m"(v->counter));
> return x;
> }
That's not precisely combining asm stuff. The compiler is ditching a whole
function because you've told it it can cache the result.
David
next prev parent reply other threads:[~2007-08-23 20:06 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-13 10:55 [PATCH 0/23] make atomic_read() and atomic_set() behavior consistent across all architectures Chris Snook
2007-08-13 11:04 ` [PATCH 1/23] document preferred use of volatile with atomic_t Chris Snook
2007-08-13 23:54 ` Paul E. McKenney
2007-08-14 22:45 ` Christoph Lameter
2007-08-14 22:53 ` Chris Snook
2007-08-14 22:56 ` Christoph Lameter
2007-08-14 23:25 ` Chris Snook
2007-08-14 23:28 ` Paul E. McKenney
2007-08-16 21:36 ` Segher Boessenkool
2007-08-13 11:06 ` [PATCH 2/23] make atomic_read() and atomic_set() behavior consistent on alpha Chris Snook
2007-08-13 11:09 ` [PATCH 3/23] make atomic_read() and atomic_set() behavior consistent on arm Chris Snook
2007-08-13 12:19 ` Russell King
2007-08-13 12:46 ` Chris Snook
2007-08-13 12:59 ` Russell King
2007-08-13 11:11 ` [PATCH 4/23] make atomic_read() and atomic_set() behavior consistent on avr32 Chris Snook
2007-08-13 11:12 ` [PATCH 5/23] make atomic_read() and atomic_set() behavior consistent on blackfin Chris Snook
2007-08-13 11:14 ` [PATCH 6/23] make atomic_read() and atomic_set() behavior consistent on cris Chris Snook
2007-08-13 11:15 ` [PATCH 7/23] make atomic_read() and atomic_set() behavior consistent on frv Chris Snook
2007-08-13 11:18 ` [PATCH 8/23] make atomic_read() and atomic_set() behavior consistent on h8300 Chris Snook
2007-08-13 11:21 ` [PATCH 9/23] make atomic_read() and atomic_set() behavior consistent on i386 Chris Snook
2007-08-13 11:23 ` [PATCH 10/23] make atomic_read() and atomic_set() behavior consistent on ia64 Chris Snook
2007-08-14 18:27 ` Luck, Tony
2007-08-14 18:48 ` Chris Snook
2007-08-14 22:06 ` Luck, Tony
2007-08-14 22:11 ` Christoph Lameter
2007-08-14 22:21 ` Chris Snook
2007-08-13 11:24 ` [PATCH 11/23] make atomic_read() and atomic_set() behavior consistent on m32r Chris Snook
2007-08-22 1:56 ` Hirokazu Takata
2007-08-22 5:00 ` Hirokazu Takata
2007-08-22 14:06 ` Chris Snook
2007-08-22 14:24 ` Segher Boessenkool
2007-08-22 18:20 ` Linus Torvalds
2007-08-23 19:29 ` Segher Boessenkool
2007-08-23 20:12 ` Linus Torvalds
2007-08-23 20:40 ` Valdis.Kletnieks
2007-08-23 20:05 ` David Howells [this message]
2007-08-13 11:26 ` [PATCH 12/23] make atomic_read() and atomic_set() behavior consistent on m68knommu Chris Snook
2007-08-13 11:28 ` [PATCH 13/23] make atomic_read() and atomic_set() behavior consistent on m68k Chris Snook
2007-08-13 11:29 ` [PATCH 14/23] make atomic_read() and atomic_set() behavior consistent on mips Chris Snook
2007-08-13 11:31 ` [PATCH 15/23] make atomic_read() and atomic_set() behavior consistent on parisc Chris Snook
2007-08-13 11:33 ` [PATCH 16/23] make atomic_read() and atomic_set() behavior consistent on s390 Chris Snook
2007-08-13 11:34 ` [PATCH 17/23] make atomic_read() and atomic_set() behavior consistent on sh64 Chris Snook
2007-08-13 11:36 ` [PATCH 18/23] make atomic_read() and atomic_set() behavior consistent on sh Chris Snook
2007-08-13 11:40 ` [PATCH 19/23] make atomic_read() and atomic_set() behavior consistent on sparc64 Chris Snook
2007-08-13 11:42 ` [PATCH 20/23] make atomic_read() and atomic_set() behavior consistent on sparc Chris Snook
2007-08-13 11:43 ` [PATCH 21/23] make atomic_read() and atomic_set() behavior consistent on v850 Chris Snook
2007-08-13 11:44 ` [PATCH 22/23] make atomic_read() and atomic_set() behavior consistent on x86_64 Chris Snook
2007-08-13 11:45 ` [PATCH 23/23] make atomic_read() and atomic_set() behavior consistent on xtensa Chris Snook
2007-08-14 9:42 ` [PATCH 7/23] make atomic_read() and atomic_set() behavior consistent on frv David Howells
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=14578.1187899540@redhat.com \
--to=dhowells@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=cfriesen@nortel.com \
--cc=csnook@redhat.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=paulmck@linux.vnet.ibm.com \
--cc=rpjday@mindspring.com \
--cc=segher@kernel.crashing.org \
--cc=takata@linux-m32r.org \
--cc=tony.luck@intel.com \
--cc=torvalds@linux-foundation.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).