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McKenney" , Frederic Weisbecker , Neeraj Upadhyay , Joel Fernandes , Josh Triplett , Boqun Feng , Uladzislau Rezki , Mathieu Desnoyers , Lai Jiangshan , Zqiang , Tejun Heo , Andrew Morton , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Anna-Maria Behnsen , Ingo Molnar , Shuah Khan , linux-kernel@vger.kernel.org, rcu@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org Subject: Re: [PATCH 07/15] watchdog: Allow runtime toggle of lockup detector affinity Message-ID: <20260325140324.GD3738786@noisy.programming.kicks-ass.net> References: <20260325-dhei-v12-final-v1-0-919cca23cadf@gmail.com> <20260325-dhei-v12-final-v1-7-919cca23cadf@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260325-dhei-v12-final-v1-7-919cca23cadf@gmail.com> X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 13B94A001A X-Stat-Signature: t91b41mjt46j9tucu6of57jq9z5f4oyf X-Rspam-User: X-HE-Tag: 1774447413-30713 X-HE-Meta: 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 4Rv8dpqE c2G8EZeOl20OCoc5qwF9cvDAhr3RHf436p2YxX0MsNkh3dvJIp8HD1djPb/jLjuZ7eeg651pYizaPu9aB2Z4Vs0nk8+DA4lzd/S+T/UlXfqCbx6n55wd0AFoZHakPie9pJvTq6tnosnBm6Xv1xOmhyJ63LWwyCdqMXZvBB9LcKK8CIJ1ssSjSD+h9DeLr18NYKVmN9ZdxhEYb4mW+1faM2nO200VCG8J82WLvfFvSrw6clz56D4UDgYaZVTFYHiB8+G8KAK8ZQZIWyk33+6jhIw6cE/m5y1sY8d65 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Mar 25, 2026 at 05:09:38PM +0800, Qiliang Yuan wrote: > The hardlockup detector threads are affined to CPUs based on the > HK_TYPE_TIMER housekeeping mask at boot. If this mask is updated at > runtime, these threads remain on their original CPUs, potentially > running on isolated cores. > > Synchronize watchdog thread affinity with HK_TYPE_TIMER updates. Doesn't the normal watchdog run off of perf, using NMIs? How is that TIMER? And again, why do you think you need more than _ONE_ mask? In the end, NOHZ_FULL needs all the masks to be the same anyway. There is absolutely no sane reason to have this much configuration space.