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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
next prev parent reply other threads:[~2008-07-29 16:36 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-29 6:23 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 --
2013-11-08 16:51 linux-next " 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
2008-10-20 12:04 linux-next: " 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
2008-08-25 11:28 Stephen Rothwell
2008-08-25 12:40 ` Ingo Molnar
2008-08-28 7:40 ` David Miller
2008-07-28 5:07 Stephen Rothwell
2008-07-28 4:44 Stephen Rothwell
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