linux-kernel - [PATCH 69/70] cpufreq: interactive: Don't set floor_validate

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Tue, 27 Oct 2015 18:30:57 +0100
From:	Bálint Czobor <czoborbalint@...il.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Viresh Kumar <viresh.kumar@...aro.org>
Cc:	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	Junjie Wu <junjiew@...eaurora.org>,
	Bálint Czobor <czoborbalint@...il.com>
Subject: [PATCH 69/70] cpufreq: interactive: Don't set floor_validate_time during boost

From: Junjie Wu <junjiew@...eaurora.org>

Frequency selection algorithm guarantees its chosen frequency
is not lower than hispeed_freq as long as boost is enabled.

Setting floor_freq and floor_validate_time during boost could block
CPU frequency from going below hispeed_freq even after
boostpulse_duration expires, if min_sample_time is higher than
boostpulse_duration. This conflicts with the intention of commit
de091367ead15b6e95dd1d0743a18f0da5a07ee5
(cpufreq: interactive: specify duration of CPU speed boost pulse)
to allow CPU to ramp down immediately after boost expires. It also
makes boost behavior inconsistent since it depends on min_sample_time.

Avoid setting floor_freq and floor_validate_time when boost starts.

Change-Id: I12852998af46cfbfaf8661eb5e8d5301b6f631e7
Signed-off-by: Junjie Wu <junjiew@...eaurora.org>
Signed-off-by: Bálint Czobor <czoborbalint@...il.com>
---
 drivers/cpufreq/cpufreq_interactive.c |    8 --------
 1 file changed, 8 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_interactive.c b/drivers/cpufreq/cpufreq_interactive.c
index 064ab56..95525b3 100644
--- a/drivers/cpufreq/cpufreq_interactive.c
+++ b/drivers/cpufreq/cpufreq_interactive.c
@@ -606,14 +606,6 @@ static void cpufreq_interactive_boost(void)
 				ktime_to_us(ktime_get());
 			anyboost = 1;
 		}
-
-		/*
-		 * Set floor freq and (re)start timer for when last
-		 * validated.
-		 */
-
-		pcpu->floor_freq = tunables->hispeed_freq;
-		pcpu->floor_validate_time = ktime_to_us(ktime_get());
 		spin_unlock_irqrestore(&pcpu->target_freq_lock, flags[1]);
 	}

-- 
1.7.9.5

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/