From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752771AbbCaWX6 (ORCPT ); Tue, 31 Mar 2015 18:23:58 -0400 Received: from g4t3427.houston.hp.com ([15.201.208.55]:35771 "EHLO g4t3427.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751138AbbCaWX4 (ORCPT ); Tue, 31 Mar 2015 18:23:56 -0400 Message-ID: <551B1E78.1040000@hp.com> Date: Tue, 31 Mar 2015 18:23:52 -0400 From: Waiman Long User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.12) Gecko/20130109 Thunderbird/10.0.12 MIME-Version: 1.0 To: Shuah Khan CC: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, Scott J Norton , Douglas Hatch Subject: Re: [PATCH] lfsr: a simple binary Galois linear feedback shift register References: <1427822889-8783-1-git-send-email-Waiman.Long@hp.com> <551AF3BD.1030800@osg.samsung.com> <551B1746.5090807@hp.com> <551B1878.8000105@osg.samsung.com> In-Reply-To: <551B1878.8000105@osg.samsung.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/31/2015 05:58 PM, Shuah Khan wrote: > On 03/31/2015 03:53 PM, Waiman Long wrote: >> On 03/31/2015 03:21 PM, Shuah Khan wrote: >>> On 03/31/2015 11:28 AM, Waiman Long wrote: >>>> This patch is based on the code sent out by Peter Zijstra as part >>>> of his queue spinlock patch to provide a hashing function with open >>>> addressing. The lfsr() function can be used to return a sequence of >>>> numbers that cycle through all the bit patterns (2^n -1) of a given >>>> bit width n except the value 0 in a somewhat random fashion depending >>>> on the LFSR tap that is being used. >>> Does this new test intended to test a new kernel feature? If so could >>> you please include what it tests in the commit log. It isn't very clear >>> to me what this test does? >>> >> This test is for checking the correctness of the lfsr.h header file. I >> will clarify that in the commit log. >> >>>> This code should be a standalone patch and not part of a larger >>>> patch series. I have also modified and extended it and added some >>>> testing code to verify the correctness of the taps that are being used. >>> The above can be left out of the commit log. >>> >> Sure. >> >>>> Signed-off-by: Waiman Long >>>> --- >>>> include/linux/lfsr.h | 84 >>>> ++++++++++++++++++++++++++++++ >>>> tools/testing/selftests/lfsr/Makefile | 11 ++++ >>>> tools/testing/selftests/lfsr/test-lfsr.c | 70 >>>> +++++++++++++++++++++++++ >>>> 3 files changed, 165 insertions(+), 0 deletions(-) >>>> create mode 100644 include/linux/lfsr.h >>>> create mode 100644 tools/testing/selftests/lfsr/Makefile >>>> create mode 100644 tools/testing/selftests/lfsr/test-lfsr.c >>> I don't see the test added to selftests/Makefile? Is it the intent >>> to leave it out of default test run and install? If this test >>> is intended to be part of selftests run and install, please add >>> it to selftests Makefile and also add install target support. >>> You can find good examples in linux-kselftest next branch. >>> Please add a .gitignore for git to ignore the binaries built. >>> >>> thanks, >>> -- Shuah >>> >>> >> Yes, it is intended to be left out of the default selftest run and >> install because the lfsr.h header is for kernel internal use and is not >> accessible from any of the kernel syscall APIs. >> > Please add this to the commit log as well that it shouldn't be included > in the default run and install. Also BUG_ON and BUILD_BUG_ON are used > in this test. These are kernel defines, hope these are included somehow. > > -- Shuah > I will update the patch once I receive feedbacks from others. The lfsr.h header does use BUG_ON and BUILD_BUG_ON, but they are disabled in the self-test. -Longman