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([2001:9e8:f12e:9401:c875:96a4:7b6f:72fd]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-bfdb4b22544sm413400966b.14.2026.06.15.00.40.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 15 Jun 2026 00:40:46 -0700 (PDT) Message-ID: <9cd444b3-aeb0-46bb-a8a3-1526aa8f191a@gmail.com> Date: Mon, 15 Jun 2026 09:40:45 +0200 Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] MIPS: smp: report dying CPU to RCU in stop_this_cpu() Content-Language: en-US To: Huacai Chen Cc: Thomas Bogendoerfer , linux-mips@vger.kernel.org, Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt , Thomas Gleixner , Jiayuan Chen , linux-rt-devel@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20260608093729.12111-1-jelonek.jonas@gmail.com> <731bd6c4-0f70-45a2-8480-8fed315b82b4@gmail.com> From: Jonas Jelonek In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 15.06.26 09:30, Huacai Chen wrote: >> [...] >> >>> However, synchronize_rcu() only gets called in the >>> IS_ENABLED(CONFIG_PREEMPT_RT) case, so I think your configuration >>> needs PREEMPT_RT, right? >>> >>> You said this is the default behavior, but PREEMPT_RT is not enabled by default. >> The condition where this is added has two parts, see [1]. While PREEMPT_RT >> isn't active for MIPS, arch_irq_work_has_interrupt gives false for MIPS (since >> there is no implementation and it falls back to the generic one). This then >> also calls synchronize_rcu. > Sorry, this is my mistake, then what's your preemption model? There > are too many config files for MIPS now. I'm using PREEMPT_NONE, apparently default for all targets in OpenWrt. > Huacai > >>> Huacai >>> >> Best, >> Jonas >> >> [1] https://elixir.bootlin.com/linux/v7.1-rc7/source/kernel/irq_work.c#L291-L302 Best, Jonas