On Thu, 2008-01-03 at 01:56 +0100, Arjan van de Ven wrote: > Subject: move WARN_ON() out of line > From: Arjan van de Ven <[EMAIL PROTECTED]> > CC: Ingo Molnar <[EMAIL PROTECTED]> > CC: Andrew Morton <[EMAIL PROTECTED]> > > A quick grep shows that there are currently 1145 instances of WARN_ON > in the kernel. Currently, WARN_ON is pretty much entirely inlined, > which makes it hard to enhance it without growing the size of the kernel > (and getting Andrew unhappy). > > This patch moves WARN_ON() out of line entirely. I've considered keeping > the test inline and moving only the slowpath out of line, but I decided > against that: an out of line test reduces the pressure on the CPUs > branch predictor logic and gives smaller code, while a function call > to a fixed location is quite fast. Likewise I've considered doing something > similar to BUG() (eg use a trapping instruction) but that's not really > better (it needs the test inline again and recovering from an invalid > instruction isn't quite fun). > > The code size reduction of this patch was about 6.5Kb (on a distro style > .config): > > text data bss dec hex filename > 3096493 293455 2760704 6150652 5dd9fc vmlinux.before > 3090006 293455 2760704 6144165 5dc0a5 vmlinux.after > > Signed-off-by: Arjan van de Ven <[EMAIL PROTECTED]>
I hate the do_foo naming scheme (how about __warn_on?), but otherwise: Acked-by: Matt Mackall <[EMAIL PROTECTED]> > + printk(KERN_WARNING "WARNING: at %s:%d %s()\n", > + __FILE__, __LINE__, __FUNCTION__); > + dump_stack(); While we're here, I'll mention that dump_stack probably ought to take a severity level argument. -- Mathematics is the supreme nostalgia of our time. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
