From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wm1-f52.google.com (mail-wm1-f52.google.com [209.85.128.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 99AEE282F1D for ; Sun, 5 Jul 2026 19:07:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.52 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783278449; cv=none; b=gL/HfTKBc8zqfb7oxVHMm3Ook/w8dIeIQeGv6yvCbKSQgEUPMJnA8+v3KGqposorOr4qXGWOWuZXwyKdER61Fu6Ze8VteU0cfKCmT88Nx2YR6ikXMWC7LcpsMSIWZDIQAu6UODcOCJf4AxFZ5aziC18Nt2szkVYmv//D+exUh2k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783278449; c=relaxed/simple; bh=bQMWND1CVbWLhE9+ejlW7rKku3PcSfGlModdR1o2f5w=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=GuW9hzYoVrUBRnxPGfnT8UNLofhd8mtx7aFd9yK9AzsjyaoxtH2x2NH8leTWPffS8H57AD0hg+av3Usdo07YG7RTstQAD+/PIwDJzMdX9eSSsLAzIawUL0wxiDWgG52IltTsXGRiT7xeKlIfoSLCGPzgIZnhAshq8xTJU6sLvPU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=VGLWFHUZ; arc=none smtp.client-ip=209.85.128.52 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="VGLWFHUZ" Received: by mail-wm1-f52.google.com with SMTP id 5b1f17b1804b1-493b7612475so20227165e9.3 for ; Sun, 05 Jul 2026 12:07:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1783278446; x=1783883246; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc:subject:date :message-id:reply-to; bh=75/6wZXM+fUJrdFetcHaQtAQajiBlyyoAEQjRiwse90=; b=VGLWFHUZpioorjctvOZgu4S1HaEnxQW7sXX2h/KimLhvWqzfbHS5lkqAw8eq4YHvI7 zvd0EiTVDVH1g4YaFfNHdBd+OOrAId3aLsPgz5jKyZBZDiIGYrmA2kmIlbh3Ajx0y3m6 7c+t/BdR1TlsztIipS5J4qpCw3wfO0RJBSzvWfbPzr9QAGpLtGErTMg+v6l/PnUZfaBe edFRqieJeuJOCZcSt1scUZmNR6ylx52uysEHqhNeeGRCb2NHrrkTf54Xyqgj/DpdReMw kfK82nxiFHELI09jmjDlj74mj8yhpHaoccOONJhCvE/6a3c8/k0e/WU97LhS63oV/JBT TGEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1783278446; x=1783883246; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=75/6wZXM+fUJrdFetcHaQtAQajiBlyyoAEQjRiwse90=; b=oYUYz/T+oYMIe3JBti27YdphgCzHIBx92M8Tvz5B054JNlkoeksvNOAF6FNKm9k7x6 oq0BZk2OR9MvQDRu2EQqlZgSAdDV9G4zpBHXfgNxrKHFbbEoHg2NvizISvDhXEEVP84m Sb6gIGhMDbw0OkERRN9bU4KOD/SY/H4TM/2VW4NGP8iOnpQBwxVrDTC1DtEZx3GAplky QJzcktVutuYKQR2CdLqaWTMQE6i6uk8OsV0Ch/N6pPR/tc4g/bEbwu7iBvKjO8XvII8L dhzSUXVkJa3uwCikXBB/Os6k4MZncI6lpBvU0+IO+HMNWoja5p/LZHQMUIQyTUX3DhGG wrMw== X-Forwarded-Encrypted: i=1; AHgh+RpbvVau+ePwP7TqdnUS2UhpHpVdgBw9EL2mHCXBbEyjJE1B7pAJGBcjWEQbgs7OrBQn++GQWM4JKZ2y08M=@vger.kernel.org X-Gm-Message-State: AOJu0Yzdxra1K/uXHB2LJXqm11mc+ALp22DmxT45/Vv8wpQh3WgeSPbY cnLgjq8N+OmJoBhgD2eUjj2VQsmYOoJ4zB4x9jCH4hU2fC5U6CA24GcH X-Gm-Gg: AfdE7cnOa3kn2cGyeou8SmJgBF2Q5gdGgN62tsoU7FaZSwW2MeIFwNcsypq2eToVOQ3 Qow9H6W3KK+PIYgVsw8Ksif1QJSeFgighb21YdGXRbxqvZ/LnU04sJHd3hNsXkVBbTpX43UzRea nDa5rxklEMxNEERL+rmiACfQ9uWMcjieizAxTpve2D76gEFDMol9g8UfuiV/ZOTXuWYCF9QpQkt piA3j0RzrmCNzawadVxxtpuQGWw71srjLfQzb4AgMk8V4CIjOGBZqgVv/Q4m7+q5AZ3S7215FWJ ja7sXaka/UbF58GJV31mAiF1LrVz69Ns0tTmDQkaNAawWWckWklA+uvLHYvmUBYZR/4aY1PunOO uoDHAaEGlPUHG6bbJG5E7dEUaprqdbLjcn7tDwkQRrlgPFbScQsLmMtcQHp156F9NghDEdBDgZG ljkGx5jOz989CcFvbvpdqZyLQOIpwdZj9p18NUFiJZLjhD0A== X-Received: by 2002:a05:600c:c166:b0:492:63c3:8eeb with SMTP id 5b1f17b1804b1-493d11fe04cmr86898625e9.35.1783278445506; Sun, 05 Jul 2026 12:07:25 -0700 (PDT) Received: from pumpkin (host-92-21-50-228.as13285.net. [92.21.50.228]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-47aa0f21543sm17317163f8f.35.2026.07.05.12.07.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 05 Jul 2026 12:07:25 -0700 (PDT) Date: Sun, 5 Jul 2026 20:07:23 +0100 From: David Laight To: Thorsten Blum Cc: Ingo Molnar , Peter Zijlstra , Juri Lelli , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , Ben Segall , Mel Gorman , Valentin Schneider , K Prateek Nayak , linux-kernel@vger.kernel.org Subject: Re: [PATCH RESEND] sched/mmcid: Use clamp() to simplify mm_cid_calc_pcpu_thrs() Message-ID: <20260705200723.66564929@pumpkin> In-Reply-To: <20260705172054.339425-2-thorsten.blum@linux.dev> References: <20260705172054.339425-2-thorsten.blum@linux.dev> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) 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-Transfer-Encoding: 7bit On Sun, 5 Jul 2026 19:20:54 +0200 Thorsten Blum wrote: > Use clamp() to simplify the code and improve its readability. > > Signed-off-by: Thorsten Blum > --- > kernel/sched/core.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 8b791e9e9f67..31739bd43176 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -10785,7 +10785,7 @@ static inline unsigned int mm_cid_calc_pcpu_thrs(struct mm_mm_cid *mc) > > opt_cids = min(mc->nr_cpus_allowed, mc->users); > /* Has to be at least 1 because 0 indicates PCPU mode off */ > - return max(min(opt_cids - opt_cids / 4, num_possible_cpus() / 2), 1); > + return clamp(opt_cids - opt_cids / 4, 1, num_possible_cpus() / 2); Nack, it isn't the same. clamp() requires that lo <= hi but I suspect num_possible_cpus() can be zero. IIRC clamp(val, lo, hi) is currently val > hi ? hi : val < lo ? lo : val so the above doesn't even generate the desired answer. But relying on the is a bug anyway. It would be nice to swap the order so that clamp(-5, 0, 5u) could be valid and have the expected value. David > } > > static bool mm_update_max_cids(struct mm_struct *mm) >