Re: [PATCH v3 19/19] perf test: Take turns using the perf mlock budget in the mmaping tests

[sashiko-bot@kernel.org]

> From: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> The mmap size used when none is asked for is derived from
> kernel.perf_event_mlock_kb itself (see perf_event_mlock_kb_in_pages()),
> that after rounding down to a power of two number of pages ends up being
> about all of a single CPU's share of that per user budget, so with 'perf
> test' starting all the selected tests at once, any further mapping done
> while another test still has its ring buffers mapped fails with:
> 
>   Permission error mapping pages.
>   Consider increasing /proc/sys/kernel/perf_event_mlock_kb,
>   or try again with a smaller value of -m/--mmap_pages.
> 
> that then shows up as a failure or, worse, as an "unsupp" skip in tests
> like the attr ones, i.e. as a false pass.
> [ ... ]
> this machine for, and the BPF metadata collection one, whose output isn't
> what the test expects, are not budget related either.
> 
> Assisted-by: LLM
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261016001843.71978-1-acme@kernel.org?part=19