linux-kernel - Re: [PATCH v3] lib/bitmap: Make count and length parameters unsigned

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Message-ID: <YtBchVNwjWk5OySA@yury-laptop>
Date:   Thu, 14 Jul 2022 11:12:21 -0700
From:   Yury Norov <yury.norov@...il.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Paul Menzel <pmenzel@...gen.mpg.de>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] lib/bitmap: Make count and length parameters unsigned

On Thu, Jul 14, 2022 at 07:47:31PM +0300, Andy Shevchenko wrote:
> On Thu, Jul 14, 2022 at 06:42:07PM +0200, Paul Menzel wrote:
> > Counts and the length are non-negative, so make them unsigned, and adapt the
> > while condition in `__bitmap_set()` and `__bitmap_clear()` accordingly.
> > 
> > For `__bitmap_set()` six less intstructions are used as a result:
> 
> You may check this by doing
> 
> 	make allyesconfig
> 	make
> 	cp vmlinux.o old
> 	# apply your patch
> 	make
> 	cp vmlinux.o new
> 	scripts/bloat-o-meter old new

For me it's:

add/remove: 0/0 grow/shrink: 19/17 up/down: 178/-404 (-226)

I'll append it to bitmap-for-next after some testing.

Thanks,
Yury