From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9CB9B14B080; Wed, 5 Feb 2025 14:05:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738764303; cv=none; b=W8tCol5JB6WWOdZtGKUvMhRyy+WE2yiFHbqqDiyW5L+mRt03i4253GEH/taKH+FDGlJIquzz9czwC0j3tz2do/C8GgLODgUjjnK2vErZ98SNg2T3daFaT/uqLUjPvTiNr3rRqpA8LBFhXwBCftJVJOL7cve/tsEegKU5QVwKklE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738764303; c=relaxed/simple; bh=HKzCX1QL8THmsGNsW3ZBtwgvfupO0oJaKeTm2QwwN+M=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=K7hwnus02VC3nmA35qoA4xW0h8oqQV7zUGJ/AC4KQCejQIOJAfquX/TzPcSiEP6/qW1+cbS2dkspBZW1vM5AHLnkly2MH6Um3hejVRiVYnPchJ147+lFg3ZdcFnYgy4uinOS7VR6CV4bQe9KukREULq8l61nY1eQ+k5Ap8Ei43w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pE5u/JjY; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="pE5u/JjY" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A7D6C4CEDD; Wed, 5 Feb 2025 14:05:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738764303; bh=HKzCX1QL8THmsGNsW3ZBtwgvfupO0oJaKeTm2QwwN+M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=pE5u/JjYDsr1eFzFO3Nx4VnEofGyToZcqnXXDM9iM99m+6ei022zZW2jH6WvfXdi9 3WLzgFMqX4l0gJhKzF6R6sU+TC/kIU4LDfLC0LvR4Pu13PS3VygOpm93RpG/6IWIUp +IvDTJqfKtdcWBPmqJ1PPrc761eABe+hA1RAw1CU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "Sultan Alsawaf (unemployed)" , Christian Loehle , "Rafael J. Wysocki" , Sasha Levin Subject: [PATCH 6.12 111/590] cpufreq: schedutil: Fix superfluous updates caused by need_freq_update Date: Wed, 5 Feb 2025 14:37:46 +0100 Message-ID: <20250205134459.505761518@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250205134455.220373560@linuxfoundation.org> References: <20250205134455.220373560@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sultan Alsawaf (unemployed) [ Upstream commit 8e461a1cb43d69d2fc8a97e61916dce571e6bb31 ] A redundant frequency update is only truly needed when there is a policy limits change with a driver that specifies CPUFREQ_NEED_UPDATE_LIMITS. In spite of that, drivers specifying CPUFREQ_NEED_UPDATE_LIMITS receive a frequency update _all the time_, not just for a policy limits change, because need_freq_update is never cleared. Furthermore, ignore_dl_rate_limit()'s usage of need_freq_update also leads to a redundant frequency update, regardless of whether or not the driver specifies CPUFREQ_NEED_UPDATE_LIMITS, when the next chosen frequency is the same as the current one. Fix the superfluous updates by only honoring CPUFREQ_NEED_UPDATE_LIMITS when there's a policy limits change, and clearing need_freq_update when a requisite redundant update occurs. This is neatly achieved by moving up the CPUFREQ_NEED_UPDATE_LIMITS test and instead setting need_freq_update to false in sugov_update_next_freq(). Fixes: 600f5badb78c ("cpufreq: schedutil: Don't skip freq update when limits change") Signed-off-by: Sultan Alsawaf (unemployed) Reviewed-by: Christian Loehle Link: https://patch.msgid.link/20241212015734.41241-2-sultan@kerneltoast.com Signed-off-by: Rafael J. Wysocki Signed-off-by: Sasha Levin --- kernel/sched/cpufreq_schedutil.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 28c77904ea749..e51d5ce730be1 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -83,7 +83,7 @@ static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) if (unlikely(sg_policy->limits_changed)) { sg_policy->limits_changed = false; - sg_policy->need_freq_update = true; + sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS); return true; } @@ -96,7 +96,7 @@ static bool sugov_update_next_freq(struct sugov_policy *sg_policy, u64 time, unsigned int next_freq) { if (sg_policy->need_freq_update) - sg_policy->need_freq_update = cpufreq_driver_test_flags(CPUFREQ_NEED_UPDATE_LIMITS); + sg_policy->need_freq_update = false; else if (sg_policy->next_freq == next_freq) return false; -- 2.39.5