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Date: Thu, 6 Jul 2006 10:23:06 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Andrew Morton <akpm@osdl.org>, linux-kernel@vger.kernel.org,
       arjan@infradead.org
Subject: Re: [patch] spinlocks: remove 'volatile'
Message-ID: <20060706082306.GA24643@elte.hu>
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* Ingo Molnar <mingo@elte.hu> wrote:

> * Linus Torvalds <torvalds@osdl.org> wrote:
> 
> > I wonder if we should remove the "volatile". There really isn't 
> > anything _good_ that gcc can do with it, but we've seen gcc code 
> > generation do stupid things before just because "volatile" seems to 
> > just disable even proper normal working.
> 
> yeah. I tried this and it indeed slashed 42K off text size (0.2%):
> 
>  text            data    bss     dec             filename
>  20779489        6073834 3075176 29928499        vmlinux.volatile
>  20736884        6073834 3075176 29885894        vmlinux.non-volatile
> 
> i booted the resulting allyesconfig bzImage and everything seems to be 
> working fine. Find patch below.

btw., this effect accounted for roughly half of the per-callsite win of 
the wait.h uninlining patch. That still leaves 18 bytes of per-callsite 
win - i'll send that patch next.

	Ingo