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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	David Miller <davem@davemloft.net>,
	linux-next@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mike Travis <travis@sgi.com>
Subject: Re: linux-next: build failure
Date: Tue, 29 Jul 2008 09:33:10 -0700 (PDT)	[thread overview]
Message-ID: <alpine.LFD.1.10.0807290927240.3334@nehalem.linux-foundation.org> (raw)
In-Reply-To: <20080729114029.GA3836@elte.hu>



On Tue, 29 Jul 2008, Ingo Molnar wrote:
> 
> the fix is simple enough.
> 
> but the question is, wont it generate huge artificial stackframes with 
> CONFIG_MAXSMP and NR_CPUS=4096?

Quite the reverse.

The "address-of statement expression" is the one that is more likely to 
generate artificial stack-frames because of a temporary variable (of 
course, I wouldn't count on it, since statement expressions are gcc 
extensions, and as such the gcc people could make up any semantics they 
want to them, including just defining that a statement expression with 
an lvalue value is the same lvalue rather than any temporary). 

In contrast, "address-of lvalue" is _guaranteed_ to not do anything stupid 
like that, and gives just the address-of.

Oh, and I was wrong about the &*x losing the 'const'. It doesn't. So I 
think Stephen's patch is fine after all - if somebody tries to modify the 
end result through the pointer, it will give a big compiler warning.

			Linus

  parent reply	other threads:[~2008-07-29 16:36 UTC|newest]

Thread overview: 96+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-07-29  6:23 linux-next: build failure Stephen Rothwell
2008-07-29  8:00 ` Ingo Molnar
2008-07-29  8:03   ` Stephen Rothwell
2008-07-29  8:58     ` Ingo Molnar
2008-07-29 11:28       ` KOSAKI Motohiro
2008-07-29 11:40         ` Ingo Molnar
2008-07-29 14:31           ` Mike Travis
2008-07-29 14:33             ` Mike Travis
2008-07-29 16:33           ` Linus Torvalds [this message]
2008-07-29 16:42             ` Ingo Molnar
2008-07-29 16:44             ` Linus Torvalds
2008-07-29  8:14   ` Wenji Huang
2008-07-29 16:26   ` Linus Torvalds
  -- strict thread matches above, loose matches on Subject: below --
2014-05-12 13:18 linux-next " Mark Salter
2014-05-12 15:47 ` Mark Salter
2014-05-12 17:05 ` Al Viro
2014-01-03 15:58 Mark Salter
2014-01-03 22:56 ` Andrew Morton
2014-01-06 15:21   ` Mark Salter
2013-11-08 16:51 Mark Salter
2013-10-30 15:27 Mark Salter
2013-10-30 20:37 ` Stephen Rothwell
2013-10-30 20:50   ` Andrew Morton
2013-10-30 23:17     ` Stephen Rothwell
     [not found] <CAHfT02u5as-YvAvwznMveNY_FbeDWLbj0NL6O78MRfeLQ5mpsA@mail.gmail.com>
2011-12-22 23:55 ` linux-next: " Carles Pey
2011-12-23  6:08   ` Stephen Rothwell
2011-12-30 19:43     ` Carles Pey
2009-04-08  4:04 Stephen Rothwell
2009-04-08  5:12 ` Alan Modra
2009-02-02  9:02 Stephen Rothwell
2009-02-02 19:43 ` Yinghai Lu
2009-02-03  6:14 ` David Miller
2009-01-08  5:20 Stephen Rothwell
2009-01-08  5:42 ` David Miller
2008-12-09  7:34 Stephen Rothwell
2008-12-09 21:05 ` Jesse Barnes
2008-11-11  8:10 Stephen Rothwell
2008-11-11  8:15 ` Sujith
2008-11-11  9:18 ` David Miller
2008-11-07  9:25 Stephen Rothwell
2008-11-07 16:40 ` Hollis Blanchard
2008-11-07 17:05   ` Josh Boyer
2008-11-07 17:24     ` Hollis Blanchard
2008-11-07 17:34       ` Josh Boyer
2008-11-07 21:18         ` Hollis Blanchard
2008-11-07 22:54   ` Stephen Rothwell
2008-11-09 15:50     ` Avi Kivity
2008-10-23  9:51 Stephen Rothwell
2008-10-23  9:18 Stephen Rothwell
2008-10-20 12:04 Stephen Rothwell
2008-10-20 15:48 ` Greg KH
2008-10-20 16:33   ` J.R. Mauro
2008-10-20 16:51     ` Greg KH
2008-10-20 20:47       ` Greg KH
2008-10-20 22:34         ` J.R. Mauro
2008-10-20 22:31   ` Stephen Rothwell
2008-10-17  8:21 Stephen Rothwell
2008-10-17 17:37 ` Greg KH
2008-10-17  7:59 Stephen Rothwell
2008-10-16  9:29 Stephen Rothwell
2008-10-16 10:39 ` Ingo Molnar
2008-10-16 16:11   ` Jeremy Fitzhardinge
2008-10-16 16:14     ` Ingo Molnar
2008-10-16  9:28 Stephen Rothwell
2008-10-16 14:00 ` Eric Van Hensbergen
2008-09-03  8:45 Stephen Rothwell
2008-09-03 10:19 ` David Woodhouse
2008-08-27  0:06 Stephen Rothwell
2008-08-27  2:55 ` Rusty Russell
2008-08-27  4:54   ` Stephen Rothwell
2008-08-25 11:28 Stephen Rothwell
2008-08-25 12:40 ` Ingo Molnar
2008-08-28  7:40 ` David Miller
2008-07-30  5:30 Stephen Rothwell
2008-07-30  5:54 ` Ananth N Mavinakayanahalli
2008-07-30  6:41 ` Adrian Bunk
     [not found]   ` <20080730064146.GA1564-re2QNgSbS3j4D6uPqz5PAwR5/fbUUdgG@public.gmane.org>
2008-07-30  7:06     ` Ankita Garg
     [not found]       ` <20080730070643.GA18347-xthvdsQ13ZrQT0dZR+AlfA@public.gmane.org>
2008-07-30 19:16         ` Bartlomiej Zolnierkiewicz
2008-07-30 23:35           ` Stephen Rothwell
2008-07-28  5:07 Stephen Rothwell
2008-07-28  4:44 Stephen Rothwell
2008-07-25  6:45 Stephen Rothwell
2008-06-30 13:22 Stephen Rothwell
2008-06-30 14:06 ` Ingo Molnar
2008-06-30 14:46   ` Stephen Rothwell
2008-06-30 15:12 ` Randy Dunlap
2008-06-30 15:49   ` Randy Dunlap
2008-06-30 23:30     ` Stephen Rothwell
2008-06-30 16:10 ` Sam Ravnborg
2008-06-30 16:44   ` Randy Dunlap
     [not found] <20080512154717.2d0947f0.sfr@canb.auug.org.au>
2008-05-12  7:54 ` David Miller
2008-05-12  8:09   ` Stephen Rothwell
2008-05-12  8:15     ` Stephen Rothwell
2008-05-12  8:53       ` David Miller
2008-05-12 10:42         ` Stephen Rothwell
2008-05-12 16:50 ` Greg KH

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