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 817B21C3F34; Mon, 10 Mar 2025 17:45:40 +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=1741628740; cv=none; b=YKwriNFkEsVeGSHDmEURPIkbm5EAnAF27cDrBvRt/P7yc3jQP/VzDDs/CKPSeuJK7i+cqV95OeYxKVmlTwx/UhCgZnAb5QBFGsqrqgVQS54ro0/APN5Bjs2KWoY2cX26nhx8QENKoa/askHWct1327/4gN0YEUZ2XXr2LkBmXBQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741628740; c=relaxed/simple; bh=r6zJKLInOJ0XXRACDxw9ZGyws2fuAbpvCCkJdg7qhEE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cGRvamNGFQemxjNEE2yVyIomnkHHgcnCC0fxB6vmyZ9Nr9jv+KucAsLQzz5eEjtFwIWXlUpus64YJAND+oZHeXpUtlQm0b68+8Yi8z9+ANNl/08LKR2mwGGdUyjvXGrGqJieRIH9CxbTkTtAX3SO18sNH/gijwd4qdtUnkVnEUM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RKwUWMJx; 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="RKwUWMJx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0B7FBC4CEE5; Mon, 10 Mar 2025 17:45:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1741628740; bh=r6zJKLInOJ0XXRACDxw9ZGyws2fuAbpvCCkJdg7qhEE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RKwUWMJxtyNeJCKqodMmA6K/9Gj2M8VUHA8yGfj433/hPFnn04DLOKXTWTrXcUGxT fzsvEZ8lNHPuF6FKws+gyw2NBV8flWL+BKhzAiGJEWeAzPS+abWqv4uOyIF4A4TTCK T3tnID185tsRDO/pyDO2X6I2fZ2fAYob5IjHdcRw= 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 5.15 053/620] cpufreq: schedutil: Fix superfluous updates caused by need_freq_update Date: Mon, 10 Mar 2025 17:58:19 +0100 Message-ID: <20250310170547.669746775@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250310170545.553361750@linuxfoundation.org> References: <20250310170545.553361750@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 5.15-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 7f6bb37d3a2f7..e23a0fc96a7d2 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -91,7 +91,7 @@ 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; } @@ -104,7 +104,7 @@ 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