From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 97D6BC001DD for ; Thu, 13 Jul 2023 14:16:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235145AbjGMOQk (ORCPT ); Thu, 13 Jul 2023 10:16:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234548AbjGMOQZ (ORCPT ); Thu, 13 Jul 2023 10:16:25 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id B044830D7; Thu, 13 Jul 2023 07:16:12 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C83601570; Thu, 13 Jul 2023 07:16:54 -0700 (PDT) Received: from [10.1.30.48] (C02Z41KALVDN.cambridge.arm.com [10.1.30.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E9EAF3F73F; Thu, 13 Jul 2023 07:16:10 -0700 (PDT) Message-ID: <062255de-90c9-72a5-dc04-714e96837fd2@arm.com> Date: Thu, 13 Jul 2023 15:16:09 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v1 3/9] selftests/mm: Skip soft-dirty tests on arm64 To: David Hildenbrand , Andrew Morton , Shuah Khan , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Mark Brown , John Hubbard , Florent Revest , "Liam R. Howlett" Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org References: <20230713135440.3651409-1-ryan.roberts@arm.com> <20230713135440.3651409-4-ryan.roberts@arm.com> <773cc0a8-24b8-7fcb-2980-7676fc772014@arm.com> <3c566e28-c7ad-7ba8-4583-619266282387@redhat.com> <373e7e67-6ccc-5508-6937-6ea5a3eed5ea@redhat.com> From: Ryan Roberts In-Reply-To: <373e7e67-6ccc-5508-6937-6ea5a3eed5ea@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org On 13/07/2023 15:12, David Hildenbrand wrote: > On 13.07.23 16:09, David Hildenbrand wrote: >> On 13.07.23 16:03, Ryan Roberts wrote: >>> On 13/07/2023 14:56, David Hildenbrand wrote: >>>> On 13.07.23 15:54, Ryan Roberts wrote: >>>>> arm64 does not support the soft-dirty PTE bit. However there are tests >>>>> in `madv_populate` and `soft-dirty` which assume it is supported and >>>>> cause spurious failures to be reported when preferred behaviour would be >>>>> to mark the tests as skipped. >>>>> >>>>> Unfortunately, the only way to determine if the soft-dirty dirty bit is >>>>> supported is to write to a page, then see if the bit is set in >>>>> /proc/self/pagemap. But the tests that we want to conditionally execute >>>>> are testing precicesly this. So if we introduced this feature check, we >>>>> could accedentally turn a real failure (on a system that claims to >>>>> support soft-dirty) into a skip. >>>>> >>>>> So instead, do the check based on architecture; for arm64, we report >>>>> that soft-dirty is not supported. This is wrapped up into a utility >>>>> function `system_has_softdirty()`, which is used to skip the whole >>>>> `soft-dirty` suite, and mark the soft-dirty tests in the `madv_populate` >>>>> suite as skipped. >>>>> >>>>> Signed-off-by: Ryan Roberts >>>>> --- >>>>>     tools/testing/selftests/mm/madv_populate.c | 18 +++++++++++++----- >>>>>     tools/testing/selftests/mm/soft-dirty.c    |  3 +++ >>>>>     tools/testing/selftests/mm/vm_util.c       | 17 +++++++++++++++++ >>>>>     tools/testing/selftests/mm/vm_util.h       |  1 + >>>>>     4 files changed, 34 insertions(+), 5 deletions(-) >>>>> >>>>> diff --git a/tools/testing/selftests/mm/madv_populate.c >>>>> b/tools/testing/selftests/mm/madv_populate.c >>>>> index 60547245e479..5a8c176d7fec 100644 >>>>> --- a/tools/testing/selftests/mm/madv_populate.c >>>>> +++ b/tools/testing/selftests/mm/madv_populate.c >>>>> @@ -232,6 +232,14 @@ static bool range_is_not_softdirty(char *start, ssize_t >>>>> size) >>>>>         return ret; >>>>>     } >>>>> >>>>> +#define ksft_test_result_if_softdirty(cond, ...)    \ >>>>> +do {                            \ >>>>> +    if (system_has_softdirty())            \ >>>>> +        ksft_test_result(cond, __VA_ARGS__);    \ >>>>> +    else                        \ >>>>> +        ksft_test_result_skip(__VA_ARGS__);    \ >>>>> +} while (0) >>>>> + >>>>>     static void test_softdirty(void) >>>>>     { >>>>>         char *addr; >>>>> @@ -246,19 +254,19 @@ static void test_softdirty(void) >>>>> >>>>>         /* Clear any softdirty bits. */ >>>>>         clear_softdirty(); >>>>> -    ksft_test_result(range_is_not_softdirty(addr, SIZE), >>>>> +    ksft_test_result_if_softdirty(range_is_not_softdirty(addr, SIZE), >>>>>                  "range is not softdirty\n"); >>>>> >>>>>         /* Populating READ should set softdirty. */ >>>>>         ret = madvise(addr, SIZE, MADV_POPULATE_READ); >>>>> -    ksft_test_result(!ret, "MADV_POPULATE_READ\n"); >>>>> -    ksft_test_result(range_is_not_softdirty(addr, SIZE), >>>>> +    ksft_test_result_if_softdirty(!ret, "MADV_POPULATE_READ\n"); >>>>> +    ksft_test_result_if_softdirty(range_is_not_softdirty(addr, SIZE), >>>>>                  "range is not softdirty\n"); >>>>> >>>>>         /* Populating WRITE should set softdirty. */ >>>>>         ret = madvise(addr, SIZE, MADV_POPULATE_WRITE); >>>>> -    ksft_test_result(!ret, "MADV_POPULATE_WRITE\n"); >>>>> -    ksft_test_result(range_is_softdirty(addr, SIZE), >>>>> +    ksft_test_result_if_softdirty(!ret, "MADV_POPULATE_WRITE\n"); >>>>> +    ksft_test_result_if_softdirty(range_is_softdirty(addr, SIZE), >>>>>                  "range is softdirty\n"); >>>> >>>> We probably want to skip the whole test_*softdirty* test instead of adding this >>>> (IMHO suboptimal) ksft_test_result_if_softdirty. >>> >>> Yeah I thought about doing it that way, but then the output just looks like >>> there were fewer tests and they all passed. But thinking about it now, I guess >>> the TAP header outputs the number of planned tests and the number of tests >>> executed are fewer, so a machine parser would still notice. I just don't like >>> that it outputs skipped:0. >>> >>> But it a lightly held view. Happy to just do: >>> >>>     if (system_has_softdirty()) >>>         test_softdirty() >>> >>> If you insist. ;-) >> >> diff --git a/tools/testing/selftests/mm/madv_populate.c >> b/tools/testing/selftests/mm/madv_populate.c >> index 60547245e479..33fda0337b32 100644 >> --- a/tools/testing/selftests/mm/madv_populate.c >> +++ b/tools/testing/selftests/mm/madv_populate.c >> @@ -266,12 +266,16 @@ static void test_softdirty(void) >>       int main(int argc, char **argv) >>    { >> +       int nr_tests = 16; >>           int err; >>              pagesize = getpagesize(); >>    +       if (system_has_softdirty()) >> +               nr_tests += 5; >> + >>           ksft_print_header(); >> -       ksft_set_plan(21); >> +       ksft_set_plan(nr_tests); >>              sense_support(); >>           test_prot_read(); >> @@ -279,7 +283,8 @@ int main(int argc, char **argv) >>           test_holes(); >>           test_populate_read(); >>           test_populate_write(); >> -       test_softdirty(); >> +       if (system_has_softdirty()) >> +               test_softdirty(); >>              err = ksft_get_fail_cnt(); >>           if (err) >> >> > > Oh, and if you want to have the skip, then you can think about converting > test_softdirty() to only perform a single ksft_test_result(), and have a single > skip on top. > > All cleaner IMHO than ksft_test_result_if_softdirty ;) I'll do it the way you recommend above. Like I said, its a lightly held opinion, and your way looks like less effort. ;-) >