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Thu, 24 Jul 2025 09:56:49 -0700 (PDT) Received: from archlinux ([2401:4900:6318:9e23:f078:c919:e302:8d2b]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-b3f6c1261e2sm1786314a12.66.2025.07.24.09.56.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Jul 2025 09:56:49 -0700 (PDT) From: Suchit Karunakaran To: catalin.marinas@arm.com, will@kernel.org, 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] arm64: allow NR_CPUS=1 for non-SMP and adjust default accordingly Date: Thu, 24 Jul 2025 22:26:39 +0530 Message-ID: <20250724165639.13926-1-suchitkarunakaran@gmail.com> X-Mailer: git-send-email 2.50.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250724_095651_304623_6D5673B2 X-CRM114-Status: GOOD ( 10.53 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The arm64 Kconfig for NR_CPUS previously required a minimum of 2 CPUs. This patch changes the minimum allowed CPUs to 1, enabling single-core non-SMP configurations. Additionally, the default value for NR_CPUS is now conditional: - Defaults to 1 if SMP is not selected (non-SMP systems) - Defaults to 512 if SMP is enabled Signed-off-by: Suchit Karunakaran --- arch/arm64/Kconfig | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 393d71124f5d..9b2970f7c5ec 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1528,9 +1528,10 @@ config SCHED_SMT places. If unsure say N here. config NR_CPUS - int "Maximum number of CPUs (2-4096)" - range 2 4096 - default "512" + int "Maximum number of CPUs (1-4096)" + range 1 4096 + default "1" if !SMP + default "512" if SMP config HOTPLUG_CPU bool "Support for hot-pluggable CPUs" -- 2.50.1