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From: Brendan Jackman <jackmanb@google.com>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	 Shuah Khan <shuah@kernel.org>
Cc: Mateusz Guzik <mjguzik@gmail.com>,
	linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
	 linux-kernel@vger.kernel.org,
	Brendan Jackman <jackmanb@google.com>
Subject: [PATCH 6/6] selftests/mm: Don't fail uffd-stress if too many CPUs
Date: Thu, 20 Feb 2025 15:03:18 +0000	[thread overview]
Message-ID: <20250220-mm-selftests-v1-6-9bbf57d64463@google.com> (raw)
In-Reply-To: <20250220-mm-selftests-v1-0-9bbf57d64463@google.com>

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.

Suggested-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Brendan Jackman <jackmanb@google.com>
---
 tools/testing/selftests/mm/uffd-stress.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
index 1facfb79e09aa4113e344d7d90dec06a37264058..f306accbef255c79bc3eeba8b9e42161a88fc10e 100644
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/tools/testing/selftests/mm/uffd-stress.c
@@ -453,6 +453,10 @@ int main(int argc, char **argv)
 	}
 
 	nr_cpus = sysconf(_SC_NPROCESSORS_ONLN);
+	if (nr_cpus > 32) {
+		/* Don't let calculation below go to zero. */
+		nr_cpus = 32;
+	}
 
 	nr_pages_per_cpu = bytes / page_size / nr_cpus;
 	if (!nr_pages_per_cpu) {

-- 
2.48.1.601.g30ceb7b040-goog



  parent reply	other threads:[~2025-02-20 15:03 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 ` Brendan Jackman [this message]
2025-02-20 15:48   ` [PATCH 6/6] selftests/mm: Don't fail uffd-stress if too many CPUs Dev Jain
2025-02-20 15:55     ` Brendan Jackman
2025-02-20 16:01       ` Brendan Jackman

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