From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7861E303C9D for ; Fri, 7 Nov 2025 06:51:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762498321; cv=none; b=jk7IXjCW0jIK1A46fQPYWNX0R8ReShisG+3153XEIcdH8LCDrynkTUfbVEK4Yxxt4HlCrjG0zXzk9Eht+AEoAOCNqMBgTBk0kSKCl6UM1nwom6PLqJj+RGidiC0kI5yfl4DFTGg3/zTjBD3QcZqnzciRlEKWOdYWfwMQTwBIlc4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762498321; c=relaxed/simple; bh=uPG2qaEExT59WP2ysS8ErG3/JwdyIv1CjufizYF4whg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=MbQ0mbG7GiatbPycHiZ/3AsZ9a1H68/GQW7YIqgY2iBEbnfDZjUqHf//xDYVLjrAKZ90kqWsY9aNmcRjYxlq+9ZIH/fONRO/RCTg4NudZ87G6WtKAnomBQE3bFRB5YGdq9xTefMboI7NruIzIpsjeCa8CEbQjjtlCgabHV8P2dM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=FMyxZLZm; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=EKzkoYgb; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="FMyxZLZm"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="EKzkoYgb" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1762498318; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=zYmb/mOjOmAnHynzCc5urdD/k2k7E8plshDwUAI/8Ps=; b=FMyxZLZmTZeDDXiBH8aKuAojectx+J4HzkWr34j6GL9ebZSNsPXm5OynGV/azzM2RINjiy RZm4MJUOMz2y/KztKTxRw8KGypOGYnoV1By+sp0/hhWFMAjLc7OEB5yFno/AjufiyKU9Ns yn6Dz9BSpOi8S2Bqpok8O6pvhSBsF64= Received: from mail-wr1-f69.google.com (mail-wr1-f69.google.com [209.85.221.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-425-edkcTVKmOlqtLM20DkyfUw-1; Fri, 07 Nov 2025 01:51:54 -0500 X-MC-Unique: edkcTVKmOlqtLM20DkyfUw-1 X-Mimecast-MFC-AGG-ID: edkcTVKmOlqtLM20DkyfUw_1762498313 Received: by mail-wr1-f69.google.com with SMTP id ffacd0b85a97d-427015f63faso154932f8f.0 for ; Thu, 06 Nov 2025 22:51:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1762498313; x=1763103113; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=zYmb/mOjOmAnHynzCc5urdD/k2k7E8plshDwUAI/8Ps=; b=EKzkoYgb4nd7vgjuHN3sK1Zb6TwwTj5huwP5mFyPhZEkqWJmsK1CbKxkuR4OyyqipT 4dY4SoijWxLLwv6FCnY0gTkdPB3sPFroiu6ObJPSGKR2DZfsnIVUVM/V5HNBZehO/uHC yTdPubeWwr4mPa0ALB6VbEv3PnWEL3HyDypmDT+qqQYV8ttzcP04HOQCFWpXFqdEYDVr kSXyhbNQY+UCP6TeoGabigtK6GzZoopwzbGQWKj6lzeHjNMGlkQbY5oZ9PjsQkKrGQaY ukbowRDKOp+EhyMWCLfxBsxwhPuGkwxsHefK+gQdB9os32BaLKhtt6TLk1lBEt9BVvJK oFvA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1762498313; x=1763103113; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=zYmb/mOjOmAnHynzCc5urdD/k2k7E8plshDwUAI/8Ps=; b=AxeGYVFxlDMLkLi7dtYWQdfrFa1FvQY0pOugmiO3S6XmOJzynZ/GJkGzoSxXdA9zwA 7fhFfcbuqBvXGvSvzQoC1nHZWL6R/2zBII1PVZg8U2ehPfmLAS6h6TllQ/+s0UDc15Bx 102COsas48eBHPFpJ/TvbRH18SABdnIrFqRFcYniFfdTgx7mUJnBbX/PqKlpW0beD6kW vDMiWj8wibFBCvae30/FLrjeEPpB6v+/Gb5j5RLbtF43W4f3dSw/CCl7NasOZZqyuJCV 24qTbcd5+w+eBv+i32n2n02cK4h4RH1d5lgWD9nhoDhBBJfxj0TPNEa3VdXewgleD+Yd LUhg== X-Forwarded-Encrypted: i=1; AJvYcCWaIA5InFx80Me+hr/0sQ3ITCbh7yHwtte/hu830bcILooQ9mxKuZUBjObysCN+XGjEN5lWaowqrhvfR7s=@vger.kernel.org X-Gm-Message-State: AOJu0YwvsgDK3vmpJPt+4nICnrPxeABXXGumOS/0GyU80bG0j1OdDACR FPz3mOz78ucGBLWgtFmpmmL6LiRf4TsNFpB5r/cXGWijz9Fja/hj4KqO8rvvShhj3lrkILzr9d2 LneCuLYS5ycCAGb1M1O4Y+fMs3n/P+VW4+Pi1+BkBLXCvRmVfUKyKldMxZbqBpiHFqA== X-Gm-Gg: ASbGncu4Hg5f39Ubfd/bwMOWA2lBZAaXRHKZtH1OifhRe8Rm0nMbuBbSGNA/6AQGd2O DBZTGeZutGfZ+QLrl5rRCLHnRHAvAOfXHDkVk+gmnXhAWl1pXxvLYZrNgsmBxPGAUPXXI7JbQaE bFZ+bgCBQY9loOYl9BzjED09TBAPoOtJHl8tIykjcCvZzS9utZ12oaAb3BZitUrQ4OBdu4LOavX 78d1jxN57Gyf665mToJJW5YAYkyVB4wPI2BGXqCA4RmNNWwIkkFUiwcrPeA3lcnfqNkCdZqFLOg ehCN1pSxZly8kX8OcOzCzQZCDb3Z6qQHmqpqXSySwmkXK/CCsja4Sqnm8VdrXAOsDalpCmR+PaO WZC7RgWlB93OISNDEyR+Wp9oSfi0NIg== X-Received: by 2002:a05:6000:18a7:b0:428:4b76:c8cd with SMTP id ffacd0b85a97d-42ae5af3d30mr1473399f8f.62.1762498312787; Thu, 06 Nov 2025 22:51:52 -0800 (PST) X-Google-Smtp-Source: AGHT+IEkTAZvSZYGErM/J0GLN/rgaF1MnsQc3qO4BrVNXh5vafIXUbVWfdF5xK+Ug878KB2EOdOBvg== X-Received: by 2002:a05:6000:18a7:b0:428:4b76:c8cd with SMTP id ffacd0b85a97d-42ae5af3d30mr1473371f8f.62.1762498312396; Thu, 06 Nov 2025 22:51:52 -0800 (PST) Received: from jlelli-thinkpadt14gen4.remote.csb ([151.29.129.40]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-42abe63dfecsm3408533f8f.12.2025.11.06.22.51.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Nov 2025 22:51:51 -0800 (PST) Date: Fri, 7 Nov 2025 07:51:49 +0100 From: Juri Lelli To: Andrea Righi Cc: Ingo Molnar , Peter Zijlstra , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , Tejun Heo , David Vernet , Changwoo Min , Shuah Khan , Joel Fernandes , Christian Loehle , Emil Tsalapatis , Luigi De Matteis , sched-ext@lists.linux.dev, bpf@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 02/11] sched/debug: Stop and start server based on if it was active Message-ID: References: <20251029191111.167537-1-arighi@nvidia.com> <20251029191111.167537-3-arighi@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On 06/11/25 17:39, Andrea Righi wrote: > On Thu, Nov 06, 2025 at 08:13:39AM +0100, Juri Lelli wrote: ... > > > @@ -376,8 +378,11 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu > > > return -EINVAL; > > > } > > > > > > - update_rq_clock(rq); > > > - dl_server_stop(&rq->fair_server); > > > + is_active = dl_server_active(&rq->fair_server); > > > + if (is_active) { > > > + update_rq_clock(rq); > > > + dl_server_stop(&rq->fair_server); > > > + } > > > > > > retval = dl_server_apply_params(&rq->fair_server, runtime, period, 0); > > > > > > @@ -385,7 +390,7 @@ static ssize_t sched_fair_server_write(struct file *filp, const char __user *ubu > > > printk_deferred("Fair server disabled in CPU %d, system may crash due to starvation.\n", > > > cpu_of(rq)); > > > > > > - if (rq->cfs.h_nr_queued) > > > + if (is_active) > > > dl_server_start(&rq->fair_server); > > > > Something that I noticed while reviewing this series is that we still > > start back a server even if the user put its runtime to zero (disabling > > it) and I don't think we want to do that. It's not of course related to > > this change or this series per-se, but something we probably want to fix > > independently. > > Should we just call dl_server_remove_params() when runtime is zero? Looking again at it I actually wonder if wouldn't it be better to use dl_server_apply_params(dl_se, 0, dl_se->dl_period, false) in both cases. dl_rq_change_utilization() deals with dl_non_contending (inactive_timer armed) case already (even though sub-optimally, but we can fix/change it later), so we can probably remove the special handling you do in dl_server_remove_params(). The WARN_ON_ONCE(on_dl_rq()) could be moved to dl_server_apply_params() as well. What do you think?