Re: [PATCH] sparc, exec: remove redundant addr_limit assignment

[Al Viro]

On Sat, Jun 11, 2011 at 04:08:42PM -0700, David Miller wrote:
> From: Mathias Krause <minipli@xxxxxxxxxxxxxx>
> Date: Fri, 10 Jun 2011 15:10:53 +0200
> 
> > The address limit is already set in flush_old_exec() so this
> > assignment of USER_DS is redundant.
> > 
> > Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
>  ...
> > @@ -368,9 +368,6 @@ void flush_thread(void)
> >  
> >  	/* Clear FPU register state. */
> >  	t->fpsaved[0] = 0;
> > -	
> > -	if (get_thread_current_ds() != ASI_AIUS)
> > -		set_fs(USER_DS);
> >  }
> 
> Yeah but now you're doing it unconditionally, the guard is here
> because the %asi register write which set_fs() does is extremely
> expensive on sparc64 and %99.99999 of the time we can avoid it.

OTOH, get_thread_current_ds() is cheap and moving that into set_fs()
itself wouldn't be particulary bad idea...
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/