From nobody Mon Feb 9 17:22:51 2026 Received: from mail-wm1-f74.google.com (mail-wm1-f74.google.com [209.85.128.74]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D001C280A33 for ; Fri, 28 Feb 2025 16:55:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.74 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740761711; cv=none; b=LFg/yJ3lbQDt5/t1Am8tra785VyfJDbmWTIPAwrQ1ZmJUhopE7eqUm6f0rqE4djv088NW9Ua77AyS5/RKZuDJYmUu2M/CV9T/Cf5WVsCtcBnuMC9pMxXKenzI3xlBiydrG0aa6WuB3ixBD7qqGO3SxiuiwP8edhiAQqSMbtLxnY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1740761711; c=relaxed/simple; bh=PKjIjTL+Xm1qQO4L3MUY1vCQdQ2UWrGB2a6naRLAZVI=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=VAq7wCxxtbsOXMzlFPNnN8cdJDBYVZhlckhf3XyjTL/5Lk+n1r8vKDP7hT9tjPhEz1tSftXBm+TH4EpIjyFhq60SbpokCYdgz7/X/q5gGARALKKGVs70y0EIGacisk8ZciO9t3q5tDhI8/0nplRtjf4pMfOiR8R0HDJmGIM5OWc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=yanSTDwU; arc=none smtp.client-ip=209.85.128.74 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--jackmanb.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="yanSTDwU" Received: by mail-wm1-f74.google.com with SMTP id 5b1f17b1804b1-4394c489babso13701525e9.1 for ; Fri, 28 Feb 2025 08:55:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1740761708; x=1741366508; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=6xd35kCXpRSECxF8AHgzbuHae7VKgf19dDjA8//S6B4=; b=yanSTDwUZemNcnsHj5ZIso9CJXS1yl2AbGCt0mGfO/WBawWQaqNRdttsh39+8FwaaQ jJnwvXc6E+kdsfJv4GHb6DeBH6UiAQl93IVqlZUZRnpd9KuZQBOmbT8sRH9MFKLgYm+b 0b7gpD3lV/UxUZCkMQYqlAB08YewwQrajBGjmGYbvwS7x/Z4qs+pcKfocdic4ulU0wKG 133CmBbK3zoADwhFNoTOV70T9T91qDQujrJOolW+4LcrkkQBbqHo0WiraMV2LH23lrzL uiisOjXo4SP5GRdE9Nr9CfcWizDpCH8pQc9b8qlNKbHFmnY5KukDBOClDJ4Hv/FsimWL +XDg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1740761708; x=1741366508; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=6xd35kCXpRSECxF8AHgzbuHae7VKgf19dDjA8//S6B4=; b=iZ9X87cyoyVgxqcQCfts1R9zukmWclLUdDvhycFdxkHIA89jWNDkBj9q4BY7cpjieo OjPS2cabfKS/sFPZphzPdZ9QlE9rTvjyXhCrJb9MHQOnIm/WLkYYqgQapjjD31gMDqjo t1cg9zug2+rJczFMhl7DfrmwUpMWXV/3TvHvS+EVToRpfsSp0FQyUZl5jxd5CF4tK1t8 BLR+iH88VHz/z4p44uyvA5gEcwxE/y5FTzVfsDvnQIxQ0J/lh2Od039ZjxEd6jFRzzy7 JmkZFYW2a9HV6uKJLOs94agREHGcTVs8E4MOT0c9yLtwp8yQpYIXN1AmplqL8LblC5rz 3UEA== X-Forwarded-Encrypted: i=1; AJvYcCW5Q/5+VLHMzoxJ6WCZjhOQxOnpxVj7o9Cac97qpaLvQ3U3f7nDpo8u45hwQPSxM3WK//Iz5nmtm7i5nXs=@vger.kernel.org X-Gm-Message-State: AOJu0YzzRvZuxYkFPviqF8OFBC3ggo0cCJP1+t+ENRk51GZyVOTxTfUQ YG4vUhSAg9rzTeNJl4gRIzf60lmRTN7Rn5bNw+cX+54NTM/6qKT8HyxbZkJgLP7SHwdXHNrI0za Boh+yt4oWxA== X-Google-Smtp-Source: AGHT+IH0ZM4UbMAKoXYRYVdsI8CLX+kx9xcCfgVmPw0K5PMtIeLgyJejHV/DAB6TfrrXG9WhtZl/va8I0oxrQA== X-Received: from wmqa14.prod.google.com ([2002:a05:600c:348e:b0:43b:6943:f013]) (user=jackmanb job=prod-delivery.src-stubby-dispatcher) by 2002:a05:600c:444d:b0:43b:8198:f6fc with SMTP id 5b1f17b1804b1-43ba66e6d07mr42105885e9.11.1740761708569; Fri, 28 Feb 2025 08:55:08 -0800 (PST) Date: Fri, 28 Feb 2025 16:54:54 +0000 In-Reply-To: <20250228-mm-selftests-v3-0-958e3b6f0203@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20250228-mm-selftests-v3-0-958e3b6f0203@google.com> X-Mailer: b4 0.15-dev Message-ID: <20250228-mm-selftests-v3-6-958e3b6f0203@google.com> Subject: [PATCH v3 06/10] selftests/mm: Don't fail uffd-stress if too many CPUs From: Brendan Jackman To: Lorenzo Stoakes , Andrew Morton , Shuah Khan Cc: Dev Jain , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Brendan Jackman , Mateusz Guzik Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable 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 Signed-off-by: Brendan Jackman Reviewed-by: Dev Jain --- tools/testing/selftests/mm/uffd-stress.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selft= ests/mm/uffd-stress.c index efe2051c393096e237d942c04a264b6611a6e127..5656128590373ed376b3b5d9259= e5ca3867a4099 100644 --- a/tools/testing/selftests/mm/uffd-stress.c +++ b/tools/testing/selftests/mm/uffd-stress.c @@ -434,6 +434,7 @@ static void sigalrm(int sig) =20 int main(int argc, char **argv) { + unsigned long nr_cpus; size_t bytes; =20 if (argc < 4) @@ -452,7 +453,15 @@ int main(int argc, char **argv) return KSFT_SKIP; } =20 - nr_threads =3D sysconf(_SC_NPROCESSORS_ONLN); + nr_cpus =3D sysconf(_SC_NPROCESSORS_ONLN); + if (nr_cpus > 32) { + /* Don't let calculation below go to zero. */ + ksft_print_msg("_SC_NPROCESSORS_ONLN (%lu) too large, capping nr_threads= to 32\n", + nr_cpus); + nr_threads =3D 32; + } else { + nr_cpus =3D nr_threads; + } =20 nr_pages_per_cpu =3D bytes / page_size / nr_threads; if (!nr_pages_per_cpu) { --=20 2.48.1.711.g2feabab25a-goog