Re: [PATCH v2 0/2] selftests/mm: separate GUP microbenchmarking from functional testing

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 19 May 2026 17:35:04 +0530 Sarthak Sharma <sarthak.sharma@arm.com> wrote:

> gup_test.c currently serves two distinct purposes: microbenchmarking
> (GUP_FAST_BENCHMARK, PIN_FAST_BENCHMARK, PIN_LONGTERM_BENCHMARK) and
> functional correctness testing (GUP_BASIC_TEST, PIN_BASIC_TEST,
> DUMP_USER_PAGES_TEST). Mixing these in a single binary means functional
> tests cannot be run or reported individually, and run_vmtests.sh must
> invoke the binary multiple times with different flag combinations to
> cover all configurations. This patch series separates the two concerns:
> tools/mm/gup_bench for benchmarking and tools/testing/selftests/mm/gup_test
> for functional testing.
> 
> Patch 1 adds tools/mm/gup_bench.c, a standalone microbenchmark for
> GUP_FAST, PIN_FAST and PIN_LONGTERM via the CONFIG_GUP_TEST debugfs
> interface. It runs the same matrix of configurations as the old
> run_gup_matrix() shell function (all three commands, read/write,
> private/shared, four page counts, THP on/off, hugetlb), but as a
> standalone C program under tools/mm with no dependency on kselftest.
> 
> Patch 2 rewrites gup_test.c as a kselftest harness-based selftest. It
> covers all five GUP kernel functions (get_user_pages, get_user_pages_fast,
> pin_user_pages, pin_user_pages_fast, pin_user_pages with FOLL_LONGTERM)
> plus DUMP_USER_PAGES_TEST, across 12 mapping configurations (THP on,
> THP off and hugetlb, each across private/shared and read/write variants)
> and four batch sizes (1, 512, 123, all pages). Results are reported as
> standard TAP output with no command-line arguments required.

Thanks.  AI review asked a few things which seem fairly minor to me,
but probably legitimate:
	https://sashiko.dev/#/patchset/20260519120506.184512-1-sarthak.sharma@arm.com