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Received: from 77-249-17-252.cable.dynamic.v4.ziggo.nl ([77.249.17.252] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1x1JRb-00000004hjW-2D31; Tue, 01 Sep 2026 08:02:11 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 2285F3002ED; Tue, 01 Sep 2026 10:02:10 +0200 (CEST) Date: Tue, 1 Sep 2026 10:02:10 +0200 From: Peter Zijlstra To: Jianyong Wu Cc: Ingo Molnar , Juri Lelli , Vincent Guittot , Chen Yu , Tim Chen , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , Shrikanth Hegde , Phil Auld , Andrew Morton , David Hildenbrand , linux-kernel@vger.kernel.org, linux-mm@kvack.org, jianyong.wu@outlook.com, zhongyuan@hygon.cn, huangsj@hygon.cn, wangfengyu@hygon.cn, yingzhiwei@hygon.cn, justin.he@arm.com Subject: Re: [RFC PATCH v2 10/23] sched/topology: Add per-sd scratch for the load balance affinity score Message-ID: <20260901080210.GP4120091@noisy.programming.kicks-ass.net> References: <20260827122816.756234-1-wujianyong@hygon.cn> <20260827122816.756234-11-wujianyong@hygon.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260827122816.756234-11-wujianyong@hygon.cn> X-Stat-Signature: ruu1o5qigrm61tgcbnfpy9dch1k75m56 X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: EC66680005 X-Rspam-User: X-HE-Tag: 1788249745-909195 X-HE-Meta: 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 ZpBsKw9G TJIFUFY7mGyG6oS12OmYlay0Xje3Sm9f/kI9XIb8kd3QsBXOKQYCCc9lnNJTj2auSCsTxe6pOuFgW1e1CFoLP9B/wpdACzzwQMkVKE6Gv7iTd1oSAjn1RuloPq8DypZjuv4znX7n013PyFscrn/izAtJTBhb1+hiP8G8eDQbG6KlrB529Xgq1Tj/Zv87uLPraHAT7JwvYUOkD0b6DeeFaCMT1Du286gHyb3vjr2aPsI+J3+M= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Aug 27, 2026 at 08:28:03PM +0800, Jianyong Wu wrote: > The affinity score computed during load balancing needs two small arrays, > one entry per LLC: the LLCs that sit closer to the balance destination than > to the source, and the weight of each. Their size is only known once the > sched domains have been built, which is why the load balancer currently has > to allocate them on every call. > > Signed-off-by: Jianyong Wu > --- > include/linux/sched/topology.h | 6 ++++++ > kernel/sched/topology.c | 28 +++++++++++++++++++++++++++- > 2 files changed, 33 insertions(+), 1 deletion(-) > > diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h > index b31d2cf16592..569ff562dbdb 100644 > --- a/include/linux/sched/topology.h > +++ b/include/linux/sched/topology.h > @@ -122,6 +122,12 @@ struct sched_domain { > unsigned int *llc_counts __counted_by_ptr(llc_max); > unsigned long llc_bytes; > unsigned int *numa_counts; > + /* > + * Scratch for the load balance affinity score, llc_max entries each. > + * Only the bottom sd owns them, like llc_counts above. > + */ > + int *affi_ids; > + int *affi_weights; Per the below, these should also have: __counted_by_ptr(llc_max), right? > #endif > + p_ids = kcalloc_node(max_lid + 1, sizeof(int), > + GFP_KERNEL, cpu_to_node(i)); > + p_w = kcalloc_node(max_lid + 1, sizeof(int), > + GFP_KERNEL, cpu_to_node(i));