From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: linux-pm@vger.kernel.org
Cc: Viresh Kumar <viresh.kumar@linaro.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
claudio@evidence.eu.com, patrick.bellasi@arm.com,
juri.lelli@redhat.com, joelaf@google.com,
linux-kernel@vger.kernel.org
Subject: [PATCH] cpufreq: schedutil: Avoid using invalid next_freq
Date: Wed, 09 May 2018 11:44:56 +0200 [thread overview]
Message-ID: <2276196.ev9rMjHTR0@aspire.rjw.lan> (raw)
In-Reply-To: <872c3f8690d9362820639d91a807e535f10a9a36.1525761635.git.viresh.kumar@linaro.org>
From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
If the next_freq field of struct sugov_policy is set to UINT_MAX,
it shouldn't be used for updating the CPU frequency (this is a
special "invalid" value), but after commit b7eaf1aab9f8 (cpufreq:
schedutil: Avoid reducing frequency of busy CPUs prematurely) it
may be passed as the new frequency to sugov_update_commit() in
sugov_update_single().
Fix that by adding an extra check for the special UINT_MAX value
of next_freq to sugov_update_single().
Fixes: b7eaf1aab9f8 (cpufreq: schedutil: Avoid reducing frequency of busy CPUs prematurely)
Reported-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.12+ <stable@vger.kernel.org> # 4.12+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
kernel/sched/cpufreq_schedutil.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
Index: linux-pm/kernel/sched/cpufreq_schedutil.c
===================================================================
--- linux-pm.orig/kernel/sched/cpufreq_schedutil.c
+++ linux-pm/kernel/sched/cpufreq_schedutil.c
@@ -305,7 +305,8 @@ static void sugov_update_single(struct u
* Do not reduce the frequency if the CPU has not been idle
* recently, as the reduction is likely to be premature then.
*/
- if (busy && next_f < sg_policy->next_freq) {
+ if (busy && next_f < sg_policy->next_freq &&
+ sg_policy->next_freq != UINT_MAX) {
next_f = sg_policy->next_freq;
/* Reset cached freq as next_freq has changed */
next prev parent reply other threads:[~2018-05-09 9:45 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-08 6:42 [PATCH] sched/schedutil: Don't set next_freq to UINT_MAX Viresh Kumar
2018-05-08 20:54 ` Rafael J. Wysocki
2018-05-09 8:41 ` Viresh Kumar
2018-05-09 8:56 ` Rafael J. Wysocki
2018-05-09 9:15 ` Viresh Kumar
2018-05-09 9:23 ` Rafael J. Wysocki
2018-05-09 9:30 ` Viresh Kumar
2018-05-09 9:32 ` Rafael J. Wysocki
2018-05-09 9:44 ` Rafael J. Wysocki [this message]
2018-05-09 9:46 ` [PATCH] cpufreq: schedutil: Avoid using invalid next_freq Viresh Kumar
2018-05-09 10:35 ` [PATCH V2] sched/schedutil: Don't set next_freq to UINT_MAX Viresh Kumar
2018-05-11 20:47 ` [V2] " Joel Fernandes
2018-05-17 10:33 ` Rafael J. Wysocki
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