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From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Rui Salvaterra <rsalvaterra@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Greg KH <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org, eunb.song@samsung.com,
	minchan@kernel.org, linux-mm@kvack.org,
	Chanho Min <chanho.min@lge.com>,
	Kyungsik Lee <kyungsik.lee@lge.com>
Subject: Re: [BUG] lib: zram lz4 compression/decompression still broken on big endian
Date: Thu, 7 Apr 2016 23:07:02 +0900	[thread overview]
Message-ID: <20160407140702.GB464@swordfish> (raw)
In-Reply-To: <CALjTZva=ocKHU8hdwmrQZvK-5QnHcc4EQD7CogJuELYk7=J=Og@mail.gmail.com>

On (04/07/16 13:33), Rui Salvaterra wrote:
[..]
> Hi again, Sergey

Hello,

> Thanks for the patch, I'll test it as soon as possible. I agree with
> your second option, usually one selects lz4 when (especially
> decompression) speed is paramount, so it needs all the help it can
> get.

thanks!

> Speaking of fishy, the 64-bit detection code also looks suspiciously
> bogus. Some of the identifiers don't even exist anywhere in the kernel
> (__ppc64__, por example, after grepping all .c and .h files).
> Shouldn't we instead check for CONFIG_64BIT or BITS_PER_LONG == 64?

definitely a good question. personally, I'd prefer to test for
CONFIG_64BIT only, looking at this hairy

  /* Detects 64 bits mode */
  #if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) \
         || defined(__ppc64__) || defined(__LP64__))

and remove/rewrite a bunch of other stuff. but the thing with cleanups
is that they don't fix anything, while potentially can introduce bugs.
it's more risky to touch the stable code. /* well, removing those 'ghost'
identifiers is sort of OK to me */. but that's just my opinion, I'll
leave it to you and Greg.

	-ss

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WARNING: multiple messages have this Message-ID (diff)
From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Rui Salvaterra <rsalvaterra@gmail.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	Greg KH <gregkh@linuxfoundation.org>,
	linux-kernel@vger.kernel.org, eunb.song@samsung.com,
	minchan@kernel.org, linux-mm@kvack.org,
	Chanho Min <chanho.min@lge.com>,
	Kyungsik Lee <kyungsik.lee@lge.com>
Subject: Re: [BUG] lib: zram lz4 compression/decompression still broken on big endian
Date: Thu, 7 Apr 2016 23:07:02 +0900	[thread overview]
Message-ID: <20160407140702.GB464@swordfish> (raw)
In-Reply-To: <CALjTZva=ocKHU8hdwmrQZvK-5QnHcc4EQD7CogJuELYk7=J=Og@mail.gmail.com>

On (04/07/16 13:33), Rui Salvaterra wrote:
[..]
> Hi again, Sergey

Hello,

> Thanks for the patch, I'll test it as soon as possible. I agree with
> your second option, usually one selects lz4 when (especially
> decompression) speed is paramount, so it needs all the help it can
> get.

thanks!

> Speaking of fishy, the 64-bit detection code also looks suspiciously
> bogus. Some of the identifiers don't even exist anywhere in the kernel
> (__ppc64__, por example, after grepping all .c and .h files).
> Shouldn't we instead check for CONFIG_64BIT or BITS_PER_LONG == 64?

definitely a good question. personally, I'd prefer to test for
CONFIG_64BIT only, looking at this hairy

  /* Detects 64 bits mode */
  #if (defined(__x86_64__) || defined(__x86_64) || defined(__amd64__) \
         || defined(__ppc64__) || defined(__LP64__))

and remove/rewrite a bunch of other stuff. but the thing with cleanups
is that they don't fix anything, while potentially can introduce bugs.
it's more risky to touch the stable code. /* well, removing those 'ghost'
identifiers is sort of OK to me */. but that's just my opinion, I'll
leave it to you and Greg.

	-ss

  reply	other threads:[~2016-04-07 13:09 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-05 14:07 [BUG] lib: zram lz4 compression/decompression still broken on big endian Rui Salvaterra
2016-04-05 14:07 ` Rui Salvaterra
2016-04-05 15:34 ` Greg KH
2016-04-05 15:34   ` Greg KH
2016-04-05 16:02   ` Rui Salvaterra
2016-04-05 16:02     ` Rui Salvaterra
2016-04-06  5:33     ` Sergey Senozhatsky
2016-04-06  5:33       ` Sergey Senozhatsky
2016-04-06  9:39       ` Rui Salvaterra
2016-04-06  9:39         ` Rui Salvaterra
2016-04-06 13:09         ` Sergey Senozhatsky
2016-04-06 13:09           ` Sergey Senozhatsky
2016-04-07 12:33           ` Rui Salvaterra
2016-04-07 12:33             ` Rui Salvaterra
2016-04-07 14:07             ` Sergey Senozhatsky [this message]
2016-04-07 14:07               ` Sergey Senozhatsky
2016-04-08 14:53               ` Rui Salvaterra
2016-04-08 14:53                 ` Rui Salvaterra

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