Date: Mon, 3 Mar 2008 22:42:31 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: Adrian Bunk <bunk@kernel.org>, Sam Ravnborg <sam@ravnborg.org>,
       Alexey Starikovskiy <aystarik@gmail.com>, lenb@kernel.org,
       astarikovskiy@suse.de, linux-acpi@vger.kernel.org,
       linux-kernel@vger.kernel.org, Arjan van de Ven <arjan@infradead.org>,
       Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [patch] x86: phase out forced inlining
Message-Id: <20080303224231.86c22ed0.akpm@linux-foundation.org>
In-Reply-To: <20080303121335.GA15381@elte.hu>
References: <20080301161902.GN25835@cs181133002.pp.htv.fi>
	<47C99FE1.8080206@gmail.com>
	<20080301183550.GC25835@cs181133002.pp.htv.fi>
	<20080303085720.GD15943@elte.hu>
	<20080303091314.GC4457@cs181133002.pp.htv.fi>
	<20080303091714.GA18250@elte.hu>
	<20080303093103.GA23651@uranus.ravnborg.org>
	<20080303103933.GC21190@elte.hu>
	<20080303113451.GF4457@cs181133002.pp.htv.fi>
	<20080303114533.GA4183@elte.hu>
	<20080303121335.GA15381@elte.hu>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1373
Lines: 35

On Mon, 3 Mar 2008 13:13:35 +0100 Ingo Molnar <mingo@elte.hu> wrote:

> +config OPTIMIZE_INLINING
> +	bool "Allow gcc to uninline functions marked 'inline'"
> +	default y
> +	help
> +	  This option determines if the kernel forces gcc to inline the functions
> +	  developers have marked 'inline'. Doing so takes away freedom from gcc to
> +	  do what it thinks is best, which is desirable for the gcc 3.x series of
> +	  compilers. The gcc 4.x series have a rewritten inlining algorithm and
> +	  disabling this option will generate a smaller kernel there. Hopefully
> +	  this algorithm is so good that allowing gcc4 to make the decision can
> +	  become the default in the future, until then this option is there to
> +	  test gcc for this.

urgh.  This will cause whatever problem
4507a6a59cfc6997e532cd812a8bd244181e6205 fixed five years ago to resurface
for incautious gcc-3.x users.

I'd suggest that this

> +#ifndef CONFIG_OPTIMIZE_INLINING

become something along the lines of

> +#ifndef CONFIG_OPTIMIZE_INLINING && (__GNUC__ > 3)

It would be nice to be able to feed the gcc version into the Kconfig logic,
really..

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/