| 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
| ||
|
Message-Id: <20200312113416.v3.1.I146403d05b9ec82f48b807efd416a57f545b447a@changeid>
Date: Thu, 12 Mar 2020 11:34:20 -0700
From: Matthias Kaehlcke <mka@...omium.org>
To: MyungJoo Ham <myungjoo.ham@...sung.com>,
Kyungmin Park <kyungmin.park@...sung.com>,
Chanwoo Choi <cw00.choi@...sung.com>,
Zhang Rui <rui.zhang@...el.com>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
Amit Kucheria <amit.kucheria@...durent.com>,
Lukasz Luba <lukasz.luba@....com>
Cc: linux-kernel@...r.kernel.org,
Leonard Crestez <leonard.crestez@....com>,
linux-pm@...r.kernel.org, Matthias Kaehlcke <mka@...omium.org>
Subject: [PATCH v3] thermal: devfreq_cooling: Use PM QoS to set frequency limits
Now that devfreq supports limiting the frequency range of a device
through PM QoS make use of it instead of disabling OPPs that should
not be used.
The switch from disabling OPPs to PM QoS introduces a subtle behavioral
change in case of conflicting requests (min > max): PM QoS gives
precedence to the MIN_FREQUENCY request, while higher OPPs disabled
with dev_pm_opp_disable() would override MIN_FREQUENCY.
Signed-off-by: Matthias Kaehlcke <mka@...omium.org>
Reviewed-by: Lukasz Luba <lukasz.luba@....com>
---
Changes in v3:
- rebased on bf3a650ab8df ("thermal: qoriq: Fix a compiling issue")
- added 'Reviewed-by' tag from Lukasz
Changes in v2:
- added documentation for 'req_max_freq'
- fixed jumps in of_devfreq_cooling_register_power() unwind
- added comment about behavioral change to the commit message
drivers/thermal/devfreq_cooling.c | 70 ++++++++++---------------------
1 file changed, 23 insertions(+), 47 deletions(-)
diff --git a/drivers/thermal/devfreq_cooling.c b/drivers/thermal/devfreq_cooling.c
index a87d4fa031c87..f7f32e98331b1 100644
--- a/drivers/thermal/devfreq_cooling.c
+++ b/drivers/thermal/devfreq_cooling.c
@@ -24,11 +24,13 @@
#include <linux/idr.h>
#include <linux/slab.h>
#include <linux/pm_opp.h>
+#include <linux/pm_qos.h>
#include <linux/thermal.h>
#include <trace/events/thermal.h>
-#define SCALE_ERROR_MITIGATION 100
+#define HZ_PER_KHZ 1000
+#define SCALE_ERROR_MITIGATION 100
static DEFINE_IDA(devfreq_ida);
@@ -54,6 +56,8 @@ static DEFINE_IDA(devfreq_ida);
* The 'res_util' range is from 100 to (power_table[state] * 100)
* for the corresponding 'state'.
* @capped_state: index to cooling state with in dynamic power budget
+ * @req_max_freq: PM QoS request for limiting the maximum frequency
+ * of the devfreq device.
*/
struct devfreq_cooling_device {
int id;
@@ -66,49 +70,9 @@ struct devfreq_cooling_device {
struct devfreq_cooling_power *power_ops;
u32 res_util;
int capped_state;
+ struct dev_pm_qos_request req_max_freq;
};
-/**
- * partition_enable_opps() - disable all opps above a given state
- * @dfc: Pointer to devfreq we are operating on
- * @cdev_state: cooling device state we're setting
- *
- * Go through the OPPs of the device, enabling all OPPs until
- * @cdev_state and disabling those frequencies above it.
- */
-static int partition_enable_opps(struct devfreq_cooling_device *dfc,
- unsigned long cdev_state)
-{
- int i;
- struct device *dev = dfc->devfreq->dev.parent;
-
- for (i = 0; i < dfc->freq_table_size; i++) {
- struct dev_pm_opp *opp;
- int ret = 0;
- unsigned int freq = dfc->freq_table[i];
- bool want_enable = i >= cdev_state ? true : false;
-
- opp = dev_pm_opp_find_freq_exact(dev, freq, !want_enable);
-
- if (PTR_ERR(opp) == -ERANGE)
- continue;
- else if (IS_ERR(opp))
- return PTR_ERR(opp);
-
- dev_pm_opp_put(opp);
-
- if (want_enable)
- ret = dev_pm_opp_enable(dev, freq);
- else
- ret = dev_pm_opp_disable(dev, freq);
-
- if (ret)
- return ret;
- }
-
- return 0;
-}
-
static int devfreq_cooling_get_max_state(struct thermal_cooling_device *cdev,
unsigned long *state)
{
@@ -135,7 +99,7 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
struct devfreq_cooling_device *dfc = cdev->devdata;
struct devfreq *df = dfc->devfreq;
struct device *dev = df->dev.parent;
- int ret;
+ unsigned long freq;
if (state == dfc->cooling_state)
return 0;
@@ -145,9 +109,10 @@ static int devfreq_cooling_set_cur_state(struct thermal_cooling_device *cdev,
if (state >= dfc->freq_table_size)
return -EINVAL;
- ret = partition_enable_opps(dfc, state);
- if (ret)
- return ret;
+ freq = dfc->freq_table[state];
+
+ dev_pm_qos_update_request(&dfc->req_max_freq,
+ DIV_ROUND_UP(freq, HZ_PER_KHZ));
dfc->cooling_state = state;
@@ -530,9 +495,15 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
if (err)
goto free_dfc;
- err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
+ err = dev_pm_qos_add_request(df->dev.parent, &dfc->req_max_freq,
+ DEV_PM_QOS_MAX_FREQUENCY,
+ PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
if (err < 0)
goto free_tables;
+
+ err = ida_simple_get(&devfreq_ida, 0, 0, GFP_KERNEL);
+ if (err < 0)
+ goto remove_qos_req;
dfc->id = err;
snprintf(dev_name, sizeof(dev_name), "thermal-devfreq-%d", dfc->id);
@@ -553,6 +524,10 @@ of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
release_ida:
ida_simple_remove(&devfreq_ida, dfc->id);
+
+remove_qos_req:
+ dev_pm_qos_remove_request(&dfc->req_max_freq);
+
free_tables:
kfree(dfc->power_table);
kfree(dfc->freq_table);
@@ -601,6 +576,7 @@ void devfreq_cooling_unregister(struct thermal_cooling_device *cdev)
thermal_cooling_device_unregister(dfc->cdev);
ida_simple_remove(&devfreq_ida, dfc->id);
+ dev_pm_qos_remove_request(&dfc->req_max_freq);
kfree(dfc->power_table);
kfree(dfc->freq_table);
--
2.25.1.481.gfbce0eb801-goog
Powered by blists - more mailing lists