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From: Brendan Jackman <jackmanb@google.com>
To: Dev Jain <dev.jain@arm.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	 Shuah Khan <shuah@kernel.org>, Mateusz Guzik <mjguzik@gmail.com>,
	linux-mm@kvack.org,  linux-kselftest@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 6/6] selftests/mm: Don't fail uffd-stress if too many CPUs
Date: Thu, 20 Feb 2025 17:01:34 +0100	[thread overview]
Message-ID: <CA+i-1C2_Ooi59HEmVma-=XF99eqHa-uZwd7DL21VtAvPg3S1EA@mail.gmail.com> (raw)
In-Reply-To: <CA+i-1C1VjdMb6YLEvORkZhiqVCE_G5BphJmAcr00U6KCfC7xtw@mail.gmail.com>

On Thu, 20 Feb 2025 at 16:55, Brendan Jackman <jackmanb@google.com> wrote:
>
> On Thu, 20 Feb 2025 at 16:48, Dev Jain <dev.jain@arm.com> wrote:
> >
> >
> >
> > On 20/02/25 8:33 pm, Brendan Jackman wrote:
> > > This calculation divides a fixed parameter by an environment-dependent
> > > parameter i.e. the number of CPUs.
> > >
> > > The simple way to avoid machine-specific failures here is to just put a
> > > cap on the max value of the latter.
> >
> > I haven't read the test, but if nr_cpus is being computed, then this
> > value must be important to the test somehow? Would it potentially be
> > wrong to let the test run for nr_cpus != actual number of cpus?
>
> Based on my _extremely hasty_ reading, the variable is misnamed and
> it's actually a thread count not a CPU count. I can double check
> that's the case and rename it.

Oh yeah actually, it's only misnamed because I made it misnamed. So
this patch needs to rename it for sure, thanks for pointing it out.

(But yeah I upgraded my extremely hasty reading to an only hasty
reading and I still don't think this test cares about the actual CPU
topology).


      reply	other threads:[~2025-02-20 16:01 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-20 15:03 [PATCH 0/6] selftests/mm: Some cleanups from trying to run them Brendan Jackman
2025-02-20 15:03 ` [PATCH 1/6] selftests/mm: Report errno when things fail Brendan Jackman
2025-02-20 15:32   ` Dev Jain
2025-02-20 15:03 ` [PATCH 2/6] selftests/mm: Fix assumption that sudo is present Brendan Jackman
2025-02-20 15:03 ` [PATCH 3/6] selftests/mm: Skip uffd-stress if userfaultfd not available Brendan Jackman
2025-02-20 18:06   ` Dev Jain
2025-02-20 18:17     ` Brendan Jackman
2025-02-20 15:03 ` [PATCH 4/6] selftests/mm: Skip uffd-wp-mremap " Brendan Jackman
2025-02-20 15:03 ` [PATCH 5/6] selftests/mm: Print some details when uffd-stress gets bad params Brendan Jackman
2025-02-20 15:17   ` Brendan Jackman
2025-02-20 15:03 ` [PATCH 6/6] selftests/mm: Don't fail uffd-stress if too many CPUs Brendan Jackman
2025-02-20 15:48   ` Dev Jain
2025-02-20 15:55     ` Brendan Jackman
2025-02-20 16:01       ` Brendan Jackman [this message]

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