From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH 6/10] lguest code: the little linux hypervisor.
Date: Fri, 09 Feb 2007 22:00:12 +1100
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To: Andrew Morton <akpm@linux-foundation.org>
Cc: lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>, Andi Kleen <ak@muc.de>, virtualization <virtualization@lists.osdl.org>, Paul Mackerras <paulus@samba.org>, Stephen Rothwell <sfr@canb.auug.org.au>
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On Fri, 2007-02-09 at 01:35 -0800, Andrew Morton wrote:
> On Fri, 09 Feb 2007 20:20:27 +1100 Rusty Russell <rusty@rustcorp.com.au> wrote:
> 
> > +#define log(...)					\
> > +	do {						\
> > +		mm_segment_t oldfs = get_fs();		\
> > +		char buf[100];				\
> > +		sprintf(buf, "lguest:" __VA_ARGS__);	\
> > +		set_fs(KERNEL_DS);			\
> > +		sys_write(1, buf, strlen(buf));		\
> > +		set_fs(oldfs);				\
> > +	} while(0)
> 
> Due to gcc shortcomings, each instance of this will chew an additional 100
> bytes of stack.  Unless they fixed it recently.  Is a bit of a timebomb.  I
> guess ksaprintf() could be used.
> 
> It also looks a bit, umm, innovative.

It's also unused 8)

It's an extremely useful macro for doing grossly invasive logging of the
guest.  I'll drop it if you prefer.

Cheers,
Rusty.