> -----Original Message----- > From: Dmitry Torokhov [mailto:dmitry.torokhov@xxxxxxxxx] > Sent: Tuesday, October 28, 2014 10:09 AM > To: Jingoo Han > Cc: linux-input@xxxxxxxxxxxxxxx; 'Viresh Kumar'; 'Jingoo Han' > Subject: Re: [PATCH] Input: spear-keyboard - Add CONFIG_PM_SLEEP to suspend/resume functions > > On October 27, 2014 5:53:56 PM PDT, Jingoo Han <jg1.han@xxxxxxxxxxx> wrote: > >On Tuesday, October 28, 2014 9:11 AM, Dmitry Torokhov wrote: > >> On Tue, Oct 28, 2014 at 09:02:44AM +0900, Jingoo Han wrote: > >> > On Tuesday, October 28, 2014 8:38 AM, Dmitry Torokhov wrote: > >> > > On Mon, Oct 27, 2014 at 09:32:58PM +0900, Jingoo Han wrote: > >> > > > Add CONFIG_PM_SLEEP to suspend/resume functions > >> > > > > >> > > > Add CONFIG_PM_SLEEP to suspend/resume functions instead of > >> > > > CONFIG_PM to fix the following build warning when > >CONFIG_PM_SLEEP > >> > > > is not selected and CONFIG_PM is selected. This is because > >sleep > >> > > > PM callbacks defined by SIMPLE_DEV_PM_OPS are only used when > >the > >> > > > CONFIG_PM_SLEEP is enabled. > >> > > > >> > > Recently I've become a fan of __maybe_unused markings as they > >insulate > >> > > us from various CONFIG changes in unrelated subsystems, I'll > >transform > >> > > this patch to use them instead. > >> > > >> > OK, I see. I have no objection. > >> > Then, how about changing other usages of CONFIG_PM_SLEEP/CONFIG_PM > >> > to __maybe_unused annotation? Personally, I prefer to increase > >build > >> > coverage than using #ifdef guards. Someone, however, argued that > >#ifdef > >> > guards should be used in this case because the size of binary can > >be > >> > reduced. How about your opinion? > >> > >> The optimizer is supposed to drop functions marked as > >'__maybe_unused' > >> if they are indeed unused so size of the binary should not change. > > > >Sorry for annoying you. > >I built 'spear-keyboard' and got the binaries as below. > > > >spear-keyboard.o 89500 bytes, <-- CONFIG_PM_SLEEP=n > >spear-keyboard.o 92352 bytes, <-- CONFIG_PM_SLEEP=y > >spear-keyboard.o 92352 bytes, <-- Marked as __maybe_unused > > > >As presented above, when CONFIG_PM_SLEEP is used instead of > >__maybe_unused, the size of binary is reduced. So, someone > >complained me to use #ifdef guards. But, I agree with your > >opinion. Personally, I DON'T want to use #ifdef guards, > >because I prefer to increase build coverage. > > What about the final kernel image size/kernel module size? I used 'spear13xx_defconfig' with linux-next(20141027). Then, I changed '#ifdef CONFIG_PM' into '#ifdef CONFIG_PM_SLEEP' as below. -#ifdef CONFIG_PM +#ifdef CONFIG_PM_SLEEP static int spear_kbd_suspend(struct device *dev) { Then, I got the following kernel images. 1. CONFIG_PM_SLEEP=y zImage 2891128 bytes spear-keyboard.o 88528 bytes 2. CONFIG_PM_SLEEP=n zImage 2842656 bytes spear-keyboard.o 85980 bytes 3. Marked as '__maybe_unused' for 'spear_kbd_suspend()/spear_kbd_resume()' instead of using '#ifdef CONFIG_PM_SLEEP', and CONFIG_PM_SLEEP=y zImage 2891160 bytes spear-keyboard.o 88528 bytes 4. Marked as '__maybe_unused' for 'spear_kbd_suspend()/spear_kbd_resume()' instead of using '#ifdef CONFIG_PM_SLEEP', and CONFIG_PM_SLEEP=n zImage 2842712 bytes spear-keyboard.o 85980 bytes Oh, sorry! Your comment is right. As you mentioned, the total sizes of the kernel and spear-keyboard.o are reduced, when '__maybe_unused' annotation is used. Thank you! Best regards, Jingoo Han > > > Thanks. > > -- > Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
