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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Lukas Wunner <lukas@wunner.de>
Cc: William Breathitt Gray <vilhelm.gray@gmail.com>,
	linus.walleij@linaro.org, bgolaszewski@baylibre.com,
	akpm@linux-foundation.org, linux-gpio@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux@rasmusvillemoes.dk, yamada.masahiro@socionext.com,
	linux-arm-kernel@lists.infradead.org, linux-pm@vger.kernel.org,
	geert@linux-m68k.org, preid@electromag.com.au,
	Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v12 01/11] bitops: Introduce the for_each_set_clump8 macro
Date: Tue, 26 Mar 2019 11:53:12 +0200	[thread overview]
Message-ID: <20190326095312.GR9224@smile.fi.intel.com> (raw)
In-Reply-To: <20190326094345.v7l7xjvfs2scbvbv@wunner.de>

On Tue, Mar 26, 2019 at 10:43:45AM +0100, Lukas Wunner wrote:
> On Tue, Mar 26, 2019 at 12:14:22PM +0900, William Breathitt Gray wrote:
> > On Mon, Mar 25, 2019 at 10:38:54AM +0100, Lukas Wunner wrote:

> > Is this the sort of implementation you had in mind:
> > 
> >         offset = find_next_bit(addr, size, offset);
> >         if (offset == size)
> >                 return size;
> > 
> >         offset -= offset % 8;
> >         *clump = bitmap_get_value8(addr, size, offset);
> > 
> >         return offset;
> 
> Almost.  I'd use round_down() instead of "offset -= offset % 8".
> Then it's just a single cheap logical and operation at runtime.

> I'd try to avoid copying around the clump value and use a pointer
> to u8 instead.

u8 might be inconvenient in environment where everything else is type of
unsigned long.

-- 
With Best Regards,
Andy Shevchenko

WARNING: multiple messages have this Message-ID (diff)
From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Lukas Wunner <lukas@wunner.de>
Cc: linux-arch@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
	linux-gpio@vger.kernel.org, yamada.masahiro@socionext.com,
	linus.walleij@linaro.org, linux-pm@vger.kernel.org,
	linux@rasmusvillemoes.dk,
	William Breathitt Gray <vilhelm.gray@gmail.com>,
	linux-kernel@vger.kernel.org, bgolaszewski@baylibre.com,
	geert@linux-m68k.org, akpm@linux-foundation.org,
	preid@electromag.com.au, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v12 01/11] bitops: Introduce the for_each_set_clump8 macro
Date: Tue, 26 Mar 2019 11:53:12 +0200	[thread overview]
Message-ID: <20190326095312.GR9224@smile.fi.intel.com> (raw)
In-Reply-To: <20190326094345.v7l7xjvfs2scbvbv@wunner.de>

On Tue, Mar 26, 2019 at 10:43:45AM +0100, Lukas Wunner wrote:
> On Tue, Mar 26, 2019 at 12:14:22PM +0900, William Breathitt Gray wrote:
> > On Mon, Mar 25, 2019 at 10:38:54AM +0100, Lukas Wunner wrote:

> > Is this the sort of implementation you had in mind:
> > 
> >         offset = find_next_bit(addr, size, offset);
> >         if (offset == size)
> >                 return size;
> > 
> >         offset -= offset % 8;
> >         *clump = bitmap_get_value8(addr, size, offset);
> > 
> >         return offset;
> 
> Almost.  I'd use round_down() instead of "offset -= offset % 8".
> Then it's just a single cheap logical and operation at runtime.

> I'd try to avoid copying around the clump value and use a pointer
> to u8 instead.

u8 might be inconvenient in environment where everything else is type of
unsigned long.

-- 
With Best Regards,
Andy Shevchenko



_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2019-03-26  9:53 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-25  6:20 [PATCH v12 00/11] Introduce the for_each_set_clump8 macro William Breathitt Gray
2019-03-25  6:20 ` William Breathitt Gray
2019-03-25  6:22 ` [PATCH v12 01/11] bitops: " William Breathitt Gray
2019-03-25  6:22   ` William Breathitt Gray
2019-03-25  9:38   ` Lukas Wunner
2019-03-25 13:09     ` Andy Shevchenko
2019-03-25 13:09       ` Andy Shevchenko
2019-03-26  3:14     ` William Breathitt Gray
2019-03-26  3:14       ` William Breathitt Gray
2019-03-26  9:43       ` Lukas Wunner
2019-03-26  9:53         ` Andy Shevchenko [this message]
2019-03-26  9:53           ` Andy Shevchenko
2019-03-26 10:08         ` William Breathitt Gray
2019-03-26 10:08           ` William Breathitt Gray
2019-03-26 10:19           ` Andy Shevchenko
2019-03-26 10:19             ` Andy Shevchenko
2019-03-26 10:28             ` William Breathitt Gray
2019-03-26 10:28               ` William Breathitt Gray
2019-03-26 13:03           ` Lukas Wunner
2019-03-26 13:18             ` Andy Shevchenko
2019-03-26 13:18               ` Andy Shevchenko
2019-03-25 13:12   ` Andy Shevchenko
2019-03-25 13:12     ` Andy Shevchenko
2019-03-26  2:54     ` William Breathitt Gray
2019-03-26  2:54       ` William Breathitt Gray
2019-03-26 11:42       ` Andy Shevchenko
2019-03-26 11:42         ` Andy Shevchenko
2019-03-25  6:23 ` [PATCH v12 02/11] lib/test_bitmap.c: Add for_each_set_clump8 test cases William Breathitt Gray
2019-03-25  6:23   ` William Breathitt Gray
2019-03-25  6:23 ` [PATCH v12 03/11] gpio: 104-dio-48e: Utilize for_each_set_clump8 macro William Breathitt Gray
2019-03-25  6:23   ` William Breathitt Gray
2019-03-25  6:23 ` [PATCH v12 04/11] gpio: 104-idi-48: " William Breathitt Gray
2019-03-25  6:23   ` William Breathitt Gray
2019-03-25  6:24 ` [PATCH v12 05/11] gpio: gpio-mm: " William Breathitt Gray
2019-03-25  6:24   ` William Breathitt Gray
2019-03-25  6:24 ` [PATCH v12 06/11] gpio: ws16c48: " William Breathitt Gray
2019-03-25  6:24   ` William Breathitt Gray
2019-03-25  6:24 ` [PATCH v12 07/11] gpio: pci-idio-16: " William Breathitt Gray
2019-03-25  6:24   ` William Breathitt Gray
2019-03-25  6:25 ` [PATCH v12 08/11] gpio: pcie-idio-24: " William Breathitt Gray
2019-03-25  6:25   ` William Breathitt Gray
2019-03-25  6:25 ` [PATCH v12 09/11] gpio: uniphier: " William Breathitt Gray
2019-03-25  6:25   ` William Breathitt Gray
2019-03-25  6:26 ` [PATCH v12 10/11] thermal: intel: intel_soc_dts_iosf: " William Breathitt Gray
2019-03-25  6:26   ` William Breathitt Gray
2019-03-25  6:26 ` [PATCH v12 11/11] gpio: 74x164: Utilize the " William Breathitt Gray
2019-03-25  6:26   ` William Breathitt Gray
2019-03-25 13:11   ` Andy Shevchenko
2019-03-25 13:11     ` Andy Shevchenko

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