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Date:   Tue, 5 Jul 2022 13:34:56 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Joel Savitz <jsavitz@redhat.com>
Cc:     linux-kernel@vger.kernel.org, Shuah Khan <shuah@kernel.org>,
        linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
        Nico Pache <npache@redhat.com>
Subject: Re: [PATCH] selftests/vm: enable running select groups of tests
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On Tue,  5 Jul 2022 14:56:05 -0400 Joel Savitz <jsavitz@redhat.com> wrote:

> Add the ability to run one or more groups of vm tests (specified
> by the environment variable TEST_ITEMS). Preserve existing default
> behavior of running all tests when TEST_ITEMS is empty or "default".

What is the reason for this?  What's the use case?

And why via the environment rather than via commandline args?