Messages in this thread | | | Subject | Re: [PATCH 1/3] selftests/zram: Remove obsolete max_comp_streams interface | From | Shuah Khan <> | Date | Wed, 26 Jan 2022 11:37:20 -0700 |
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On 1/26/22 11:24 AM, Petr Vorel wrote: >> On 1/26/22 12:13 AM, Petr Vorel wrote: >>> Hi all, > >>>> on 2022/1/26 4:33, Shuah Khan wrote : >>>>> On 12/15/21 2:56 AM, Yang Xu wrote: >>>>>> Since kernel commit 43209ea2d17a ("zram: remove max_comp_streams >>>>>> internals"), zram has >>>>>> switched to per-cpu streams. Even kernel still keep this interface for >>>>>> some reasons, but >>>>>> writing to max_comp_stream doesn't take any effect. So remove it. > >>>>> I get that max_comp_stream doesn't do anything since this referenced >>>>> commit. Don't we need this test on older kernels since older kernels >>>>> still support max_comp_stream? > >>>> I read the following info from kernel selftest documentation >>>> https://www.kernel.org/doc/html/latest/dev-tools/kselftest.html > >>>> "The kernel contains a set of “self tests” under the >>>> tools/testing/selftests/ directory. These are intended to be small tests >>>> to exercise individual code paths in the kernel. Tests are intended to >>>> be run after building, installing and booting a kernel." > >>>> So, we can build older kernel(use older kernel source) if we want to >>>> test older kernel. > >>>> IMO, kernel selftest is different from other testsuit(ie ltp, this >>>> shuould think about api changes because ltp may test on different kernel). >>> Yes, that's how I understand the difference with approach of in kselftest - the >>> kernel tree testsuite and LTP - the out-of-tree testsuite. > > >> Removing max_comp_stream test appears to be motivated by the fact it isn't >> needed on newer kernels. > >> Kselftest from mainline can be run on older stable kernels. This is a use-case >> for a lot test rings. The idea is that when a new test gets added for older >> code to regression test a bug, we should be able to run that test on an older >> kernel. This is the reason why we don't remove code that can still test an older >> kernel and make sure it skips gracefully. > > Thanks for clarifying this approach. It might be worth of documenting it in > dev-tools/kselftest.rst. >
I will send out a patch clarifying this.
thanks, -- Shuah
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