Messages in this thread | | | Date | Tue, 4 Mar 2008 02:26:58 +0300 | From | Anton Vorontsov <> | Subject | Re: [PATCH RFC] introduce pm_call() macro to get rid of most #ifdef CONFIG_PM |
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On Sun, Mar 02, 2008 at 04:08:20PM -0800, Arjan van de Ven wrote: > On Mon, 3 Mar 2008 02:43:08 +0300 > Anton Vorontsov <cbouatmailru@gmail.com> wrote: > > > Currently drivers handle CONFIG_PM this way: > > > > #ifdef CONFIG_PM > > drv_suspend() {} > > drv_resume() {} > > #else > > #define drv_suspend NULL > > #define drv_resume NULL > > #endif > > > > struct driver drv = { > > .suspend = drv_suspend, > > .resume = drv_resume, > > }; > > > > With this patch, the code above converts into: > > > > drv_suspend() {} > > drv_resume() {} > > > > struct driver drv = { > > .suspend = pm_call(drv_suspend), > > .resume = pm_call(drv_resume), > > }; > > > > GCC will optimize away suspend/resume calls if they're really > > not used. > > > > > to be honest, at this point I would think it's time to remove > CONFIG_PM, or rather, > just make it always be there and just get rid of the ifdefs.
Don't be so CONFIG_PM-centric :-)
$ zcat /proc/config.gz | grep CONFIG_PM # CONFIG_PM is not set
This is machine I use at home.
> We're saving 2 words and a bit of code, > but only a case that not even the embedded guys use.
Well, on my ARM machine, with CONFIG_PM=y vmlinux grows by 30KB, half of that is in drivers/. 30KB is 1% of the vmlinux. Is it enough to worth saving? I don't know.
On a x86 box, CONFIG_PM=y grows the vmlinux by 400KB (yeah, it's including ACPI and stuff), though here I didn't count drivers' suspend/resume hooks contribution share.
-- Anton Vorontsov email: cbouatmailru@gmail.com irc://irc.freenode.net/bd2
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