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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Yury Norov <yury.norov@gmail.com>
Cc: Alexander Potapenko <glider@google.com>,
	catalin.marinas@arm.com, will@kernel.org, pcc@google.com,
	andreyknvl@gmail.com, linux@rasmusvillemoes.dk,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, eugenis@google.com,
	syednwaris@gmail.com, william.gray@linaro.org,
	Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v4 1/5] lib/bitmap: add bitmap_{set,get}_value()
Date: Tue, 25 Jul 2023 12:00:09 +0300	[thread overview]
Message-ID: <ZL+PGXMOf18Kc5Cu@smile.fi.intel.com> (raw)
In-Reply-To: <ZL9X0TZb/QhCbEiC@yury-ThinkPad>

On Mon, Jul 24, 2023 at 10:04:34PM -0700, Yury Norov wrote:
> On Mon, Jul 24, 2023 at 11:36:36AM +0300, Andy Shevchenko wrote:
> > On Sat, Jul 22, 2023 at 06:57:23PM -0700, Yury Norov wrote:
> > > On Thu, Jul 20, 2023 at 07:39:52PM +0200, Alexander Potapenko wrote:

...

> > > 'GENMASK(nbits - 1, 0) << offset' looks really silly.
> > 
> > But you followed the thread to get a clue why it's written in this form, right?
> 
> Yes, I did. But I don't expect everyone looking at kernel code would spend
> time recovering discussions that explain why that happened. So, at least it
> would be fine to drop a comment.

See also below.

...

>           w = *map & (end < BITS_PER_LONG ? ~GENMASK(end, start) : BITMAP_LAST_WORD_MASK(start));

This GENMASK() may generate worse code as compiler uses more instructions
instead of simple approach with the above..

...

> bitmap_write                                   -     271    +271
> my_bitmap_write                                -     248    +248
> bitmap_read                                    -     229    +229

my_ -- means your proposal? Do you mean you have it better in size than original one?

-- 
With Best Regards,
Andy Shevchenko



  reply	other threads:[~2023-07-25  9:00 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-07-20 17:39 [PATCH v4 0/5] Implement MTE tag compression for swapped pages Alexander Potapenko
2023-07-20 17:39 ` [PATCH v4 1/5] lib/bitmap: add bitmap_{set,get}_value() Alexander Potapenko
2023-07-23  1:57   ` Yury Norov
2023-07-23 15:38     ` Yury Norov
2023-09-22  7:48       ` Alexander Potapenko
2023-07-24  8:36     ` Andy Shevchenko
2023-07-25  5:04       ` Yury Norov
2023-07-25  9:00         ` Andy Shevchenko [this message]
2023-07-26  8:08     ` Alexander Potapenko
2023-07-27  0:14       ` Yury Norov
2023-08-04 16:07         ` Alexander Potapenko
2023-08-04 19:55           ` Yury Norov
2023-08-04 20:05             ` Andy Shevchenko
2023-09-22  7:49             ` Alexander Potapenko
2023-09-22  7:47     ` Alexander Potapenko
2023-07-20 17:39 ` [PATCH v4 2/5] lib/test_bitmap: add tests for bitmap_{set,get}_value() Alexander Potapenko
2023-07-23  2:29   ` Yury Norov
2023-09-22  7:57     ` Alexander Potapenko
2023-09-22 13:28       ` Yury Norov
2023-09-27 12:33         ` Alexander Potapenko
2023-07-20 17:39 ` [PATCH v4 3/5] arm64: mte: implement CONFIG_ARM64_MTE_COMP Alexander Potapenko
2023-07-21 11:22   ` Andy Shevchenko
2023-09-22  8:03     ` Alexander Potapenko
2023-08-18 17:57   ` Catalin Marinas
2023-09-22  8:04     ` Alexander Potapenko
2023-07-20 17:39 ` [PATCH v4 4/5] arm64: mte: add a test for MTE tags compression Alexander Potapenko
2023-07-21 11:25   ` Andy Shevchenko
2023-09-22  8:05     ` Alexander Potapenko
2023-07-20 17:39 ` [PATCH v4 5/5] arm64: mte: add compression support to mteswap.c Alexander Potapenko
2023-08-18 18:18   ` Catalin Marinas
2023-09-20 13:26     ` Alexander Potapenko
2023-09-20 16:18       ` Alexander Potapenko
2023-09-20 14:22     ` Alexander Potapenko

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