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Thu, 24 Jul 2025 10:26:15 -0700 (PDT) Received: from archlinux ([205.254.163.122]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-761ae1584bfsm1999495b3a.38.2025.07.24.10.26.08 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Jul 2025 10:26:14 -0700 (PDT) From: Suchit Karunakaran To: linux@armlinux.org.uk, rmk+kernel@armlinux.org.uk, ardb@kernel.org, linus.walleij@linaro.org, ebiggers@google.com, nathan@kernel.org, lumag@kernel.org, dave@vasilevsky.ca, ruanjinjie@huawei.com, kees@kernel.org, liuyuntao12@huawei.com, linux-arm-kernel@lists.infradead.org Cc: skhan@linuxfoundation.org, linux-kernel-mentees@lists.linux.dev, linux-kernel@vger.kernel.org, Suchit Karunakaran Subject: [PATCH] arm: allow single CPU configuration by adjusting NR_CPUS range and defaults Date: Thu, 24 Jul 2025 22:56:03 +0530 Message-ID: <20250724172603.18701-1-suchitkarunakaran@gmail.com> X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Previously, the NR_CPUS config for ARM required a minimum of 2 CPUs. This patch changes the minimum NR_CPUS to 1 when SMP is not enabled, sets range to exactly 1 if !SMP, allowing only a single CPU setting and adds conditional defaults: - default to 1 if SMP is disabled (uniprocessor) - default to 4 if SMP is enabled (multiprocessor) Signed-off-by: Suchit Karunakaran --- arch/arm/Kconfig | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 3072731fe09c..23acee38721e 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1063,11 +1063,13 @@ config KASAN_SHADOW_OFFSET default 0xffffffff =20 config NR_CPUS - int "Maximum number of CPUs (2-32)" + int "Maximum number of CPUs (1-32)" + range 1 1 if !SMP range 2 16 if DEBUG_KMAP_LOCAL range 2 32 if !DEBUG_KMAP_LOCAL depends on SMP - default "4" + default "1" if !SMP + default "4" if SMP help The maximum number of CPUs that the kernel can support. Up to 32 CPUs can be supported, or up to 16 if kmap_local() --=20 2.50.1