From patchwork Sun May 19 21:03:59 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Loehle X-Patchwork-Id: 797821 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 2E4B026AEC; Sun, 19 May 2024 21:04:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716152652; cv=none; b=u9lp1lx8C5lwTVudZpg9Cdg7jFQV68SNQ+glPQOb/WJTdgm/fv+h9kc1nYvuToJ1ICk0yx05a7fwbcJ+sSl/4mQR6z1JFwFSVuzVrC71iyLjWbtaCBx4CUNKn1qzxHQ/7QTjjSATiT/FLTeIdVm9wxh/GJssCF9EFwpK4sSBT5c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1716152652; c=relaxed/simple; bh=d9zC13sd+PcOp2vUU2yC7M1ViEVGOliY1ayJq7D3KmI=; h=Message-ID:Date:MIME-Version:To:Cc:From:Subject:Content-Type; b=DGxaBhvH3r1XGjCdT+alrEB02Enyos6yEiqFepoINZwcrOyY4Sv7newVk5P/6vWJE6lsnRB1yK++w6v3a6ITCPljGGFQ1txSdBs/vxReWn3fQWiPY7x3EB+yQjmdn7kjIdYXd1DacNyZJtqFZSn9evFmAgfhLDNaSc4tjPX6oO0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id F261F1007; Sun, 19 May 2024 14:04:26 -0700 (PDT) Received: from [10.57.85.2] (unknown [10.57.85.2]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 701D73F762; Sun, 19 May 2024 14:04:01 -0700 (PDT) Message-ID: <0ce2d536-1125-4df8-9a5b-0d5e389cd8af@arm.com> Date: Sun, 19 May 2024 22:03:59 +0100 Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: "linux-kernel@vger.kernel.org" , linux-pm@vger.kernel.org, "Rafael J. Wysocki" , Daniel Lezcano Cc: Qais Yousef , kajetan.puchalski@arm.com, Anna-Maria Behnsen From: Christian Loehle Subject: [PATCH] cpuidle: teo: fix underflow of recent intercepts The recent counter of each cpuidle state bin reflects the number of recent intercepts. It's decremented and incremented accordingly. The decrement was never checked for 0, therefore underflowing into a value teo cannot easily recover from. The underflow lead to deeper idle states being skipped because teo assumed interception was likely and it preferring shallower states. Fixes: 77577558f25d ("cpuidle: teo: Rework most recent idle duration values treatment") Signed-off-by: Christian Loehle Signed-off-by: Christian Loehle --- drivers/cpuidle/governors/teo.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/cpuidle/governors/teo.c b/drivers/cpuidle/governors/teo.c index 7244f71c59c5..42fb2771e35d 100644 --- a/drivers/cpuidle/governors/teo.c +++ b/drivers/cpuidle/governors/teo.c @@ -290,7 +290,8 @@ static void teo_update(struct cpuidle_driver *drv, struct cpuidle_device *dev) if (cpu_data->next_recent_idx >= NR_RECENT) cpu_data->next_recent_idx = 0; - if (cpu_data->recent_idx[i] >= 0) + if (cpu_data->recent_idx[i] >= 0 && + cpu_data->state_bins[cpu_data->recent_idx[i]].recent) cpu_data->state_bins[cpu_data->recent_idx[i]].recent--; /*