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Thu, 07 Jul 2022 06:43:09 -0700 (PDT) Message-ID: <6802d78e-5aeb-6115-a4ec-73be78ccc577@bytedance.com> Date: Thu, 7 Jul 2022 21:43:00 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.0 Subject: Re: [RFC PATCH 1/2] arm64: run softirqs on the per-CPU IRQ stack Content-Language: en-US To: Arnd Bergmann Cc: Catalin Marinas , Will Deacon , Linux ARM , Linux Kernel Mailing List , Sebastian Andrzej Siewior References: <20220707110511.52129-1-zhengqi.arch@bytedance.com> <20220707110511.52129-2-zhengqi.arch@bytedance.com> From: Qi Zheng In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220707_064316_092592_ED0B81C1 X-CRM114-Status: GOOD ( 18.61 ) 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: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2022/7/7 20:58, Arnd Bergmann wrote: > On Thu, Jul 7, 2022 at 1:05 PM Qi Zheng wrote: >> >> Currently arm64 supports per-CPU IRQ stack, but softirqs >> are still handled in the task context. >> >> Since any call to local_bh_enable() at any level in the task's >> call stack may trigger a softirq processing run, which could >> potentially cause a task stack overflow if the combined stack >> footprints exceed the stack's size, let's run these softirqs >> on the IRQ stack as well. >> >> Signed-off-by: Qi Zheng > > I think this is the correct approach, but your patch conflicts with another > patch I have queued up in the asm-generic tree, see > https://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic.git/commit/?h=asm-generic&id=f2c5092190f21 > > Please adapt accordingly. OK, will do in the next version. > > Are there any architectures left that use IRQ stacks but don't > set HAVE_SOFTIRQ_ON_OWN_STACK? If not, we could > also consider removing the Kconfig symbol and just requiring > it to be done this way (for non-PREEMPT_RT). I haven't taken a close look at other architectures than x86 and arm, but I think it's a good idea. Thanks, Qi > > Arnd -- Thanks, Qi _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel