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 2E37EC001DD for ; Thu, 13 Jul 2023 14:14:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234866AbjGMOOX (ORCPT ); Thu, 13 Jul 2023 10:14:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229797AbjGMOOV (ORCPT ); Thu, 13 Jul 2023 10:14:21 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 61FA226B2; Thu, 13 Jul 2023 07:14:10 -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 893AF1570; Thu, 13 Jul 2023 07:14:52 -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 A485A3F73F; Thu, 13 Jul 2023 07:14:08 -0700 (PDT) Message-ID: <556d05f0-7103-1079-fce1-1fb6bd40b17c@arm.com> Date: Thu, 13 Jul 2023 15:14:07 +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> From: Ryan Roberts In-Reply-To: <3c566e28-c7ad-7ba8-4583-619266282387@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 13/07/2023 15:09, 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; This is the opposite of the point I was trying to make; If there are 21 tests in a suite, I'd like to know that there are 21 tests, 16 of which passed and 5 of which were skipped. This will hide the 5 from the test report. > + >         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) > >