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([2601:600:947f:f020:85dc:d2b2:c5ee:e3c4]) by smtp.gmail.com with ESMTPSA id 46e09a7af769-73afafee51bsm1722599a34.10.2025.06.30.10.04.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 30 Jun 2025 10:04:23 -0700 (PDT) From: Waiman Long X-Google-Original-From: Waiman Long Message-ID: <495e2880-db0c-45d5-9cbc-e9299ba8a6b8@redhat.com> Date: Mon, 30 Jun 2025 13:04:21 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/5] sched/deadline: Initialize dl_servers after SMP To: Juri Lelli , Waiman Long Cc: Ingo Molnar , Peter Zijlstra , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , linux-kernel@vger.kernel.org, Marcel Ziswiler , Luca Abeni References: <20250627115118.438797-1-juri.lelli@redhat.com> <20250627115118.438797-2-juri.lelli@redhat.com> <1e39c473-d161-4ad0-bfdc-8a306f57135f@redhat.com> Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 6/30/25 6:21 AM, Juri Lelli wrote: > On 29/06/25 18:48, Waiman Long wrote: >> On 6/27/25 7:51 AM, Juri Lelli wrote: > ... > >>> @@ -1652,6 +1664,8 @@ int dl_server_apply_params(struct sched_dl_entity *dl_se, u64 runtime, u64 perio >>> int retval = 0; >>> int cpus; >>> + guard(rcu)(); >>> + >> Your patch doesn't explain why a RCU guard is needed here? >> sched_init_dl_servers() is the changed caller, but it is called with >> rq_lock_irq held which should implies a RCU read critical section as IRQ is >> disabled. > Yeah, looks like it's not required. Will remove. Thanks for spotting it! Other than this minor nit, the patch series look good to me with my limited understanding about the DL scheduler. Acked-by: Waiman Long