Re: [PATCH v4 4/4] PM / QoS: Restore DEV_PM_QOS_MIN/MAX_FREQUENCY

On 26.11.2019 23:01, Matthias Kaehlcke wrote:

On Tue, Nov 26, 2019 at 05:17:13PM +0200, Leonard Crestez wrote:

...

Support for adding per-device frequency limits was removed in commit 2aac8bdf7a0f ("PM: QoS: Drop frequency QoS types from device PM QoS") after cpufreq switched to use a new "freq_constraints" construct.

Restore support for per-device freq limits but base this upon freq_constraints. This is primarily meant to be used by the devfreq subsystem.

This removes the "static" marking on freq_qos_apply but does not export it for modules.

Signed-off-by: Leonard Crestez leonard.crestez@nxp.com

drivers/base/power/qos.c | 73 ++++++++++++++++++++++++++++++++++++---- include/linux/pm_qos.h | 12 +++++++ kernel/power/qos.c | 4 ++- 3 files changed, 82 insertions(+), 7 deletions(-)

diff --git a/drivers/base/power/qos.c b/drivers/base/power/qos.c index 350dcafd751f..8e93167f1783 100644 --- a/drivers/base/power/qos.c +++ b/drivers/base/power/qos.c @@ -113,14 +113,24 @@ s32 dev_pm_qos_read_value(struct device *dev, enum dev_pm_qos_req_type type) unsigned long flags; s32 ret; spin_lock_irqsave(&dev->power.lock, flags);

• if (type == DEV_PM_QOS_RESUME_LATENCY) {

• switch (type) {
• case DEV_PM_QOS_RESUME_LATENCY: ret = IS_ERR_OR_NULL(qos) ? PM_QOS_RESUME_LATENCY_NO_CONSTRAINT : pm_qos_read_value(&qos->resume_latency);

• } else {

• break;
  

• case DEV_PM_QOS_MIN_FREQUENCY:

• ret = IS_ERR_OR_NULL(qos) ? PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE
  

• 	: freq_qos_read_value(&qos->freq, FREQ_QOS_MIN);
  

• break;
  

• case DEV_PM_QOS_MAX_FREQUENCY:

• ret = IS_ERR_OR_NULL(qos) ? PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE
  

• 	: freq_qos_read_value(&qos->freq, FREQ_QOS_MAX);
  

• break;
  

• default: WARN_ON(1); ret = 0; }

spin_unlock_irqrestore(&dev->power.lock, flags); @@ -157,10 +167,14 @@ static int apply_constraint(struct dev_pm_qos_request *req, if (ret) { value = pm_qos_read_value(&qos->latency_tolerance); req->dev->power.set_latency_tolerance(req->dev, value); } break;

• case DEV_PM_QOS_MIN_FREQUENCY:
• case DEV_PM_QOS_MAX_FREQUENCY:

• ret = freq_qos_apply(&req->data.freq, action, value);
  

• break;
  

  case DEV_PM_QOS_FLAGS: ret = pm_qos_update_flags(&qos->flags, &req->data.flr, action, value); break; default:

@@ -207,10 +221,12 @@ static int dev_pm_qos_constraints_allocate(struct device *dev) c->target_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE; c->default_value = PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE; c->no_constraint_value = PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT; c->type = PM_QOS_MIN;

• freq_constraints_init(&qos->freq);
• INIT_LIST_HEAD(&qos->flags.list);

spin_lock_irq(&dev->power.lock); dev->power.qos = qos; spin_unlock_irq(&dev->power.lock); @@ -267,10 +283,24 @@ void dev_pm_qos_constraints_destroy(struct device *dev) plist_for_each_entry_safe(req, tmp, &c->list, data.pnode) { apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); memset(req, 0, sizeof(*req)); }

• c = &qos->freq.min_freq;
• plist_for_each_entry_safe(req, tmp, &c->list, data.freq.pnode) {

• apply_constraint(req, PM_QOS_REMOVE_REQ,
  

• 		 PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE);
  

• memset(req, 0, sizeof(*req));
  

• }
• c = &qos->freq.max_freq;
• plist_for_each_entry_safe(req, tmp, &c->list, data.freq.pnode) {

• apply_constraint(req, PM_QOS_REMOVE_REQ,
  

• 		 PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE);
  

• memset(req, 0, sizeof(*req));
  

• }

nit: these loops look a bit redundant, might be worth to encapsulate them in a macro.

There are only 2 identical loops though? Other requests to be cleared are enumerated in slightly different ways.

A pm_qos_for_each_request macro could be added but it would only be used in a handful of places.

...

f = &qos->flags; list_for_each_entry_safe(req, tmp, &f->list, data.flr.node) { apply_constraint(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE); memset(req, 0, sizeof(*req)); } @@ -312,15 +342,26 @@ static int __dev_pm_qos_add_request(struct device *dev, ret = -ENODEV; else if (!dev->power.qos) ret = dev_pm_qos_constraints_allocate(dev); trace_dev_pm_qos_add_request(dev_name(dev), type, value);

• if (!ret) {

• req->dev = dev;
  

• req->type = type;
  

• if (ret)

• return ret;
  

• req->dev = dev;
• req->type = type;
• if (req->type == DEV_PM_QOS_MIN_FREQUENCY)

• ret = freq_qos_add_request(&dev->power.qos->freq,
  

• 			   &req->data.freq,
  

• 			   FREQ_QOS_MIN, value);
  

• else if (req->type == DEV_PM_QOS_MAX_FREQUENCY)

• ret = freq_qos_add_request(&dev->power.qos->freq,
  

• 			   &req->data.freq,
  

• 			   FREQ_QOS_MAX, value);
  

• else ret = apply_constraint(req, PM_QOS_ADD_REQ, value);

• }

• return ret; }

/**

• dev_pm_qos_add_request - inserts new qos request into the list

@@ -380,10 +421,14 @@ static int __dev_pm_qos_update_request(struct dev_pm_qos_request *req, switch(req->type) { case DEV_PM_QOS_RESUME_LATENCY: case DEV_PM_QOS_LATENCY_TOLERANCE: curr_value = req->data.pnode.prio; break;

• case DEV_PM_QOS_MIN_FREQUENCY:
• case DEV_PM_QOS_MAX_FREQUENCY:

• curr_value = req->data.freq.pnode.prio;
  

• break;
  

  case DEV_PM_QOS_FLAGS: curr_value = req->data.flr.flags; break; default: return -EINVAL;

@@ -505,10 +550,18 @@ int dev_pm_qos_add_notifier(struct device *dev, struct notifier_block *notifier, switch (type) { case DEV_PM_QOS_RESUME_LATENCY: ret = blocking_notifier_chain_register(dev->power.qos->resume_latency.notifiers, notifier); break;

• case DEV_PM_QOS_MIN_FREQUENCY:

• ret = freq_qos_add_notifier(&dev->power.qos->freq,
  

• 			    FREQ_QOS_MIN, notifier);
  

• break;
  

• case DEV_PM_QOS_MAX_FREQUENCY:

• ret = freq_qos_add_notifier(&dev->power.qos->freq,
  

• 			    FREQ_QOS_MAX, notifier);
  

• break;
  

  default: WARN_ON(1); ret = -EINVAL; }

@@ -544,10 +597,18 @@ int dev_pm_qos_remove_notifier(struct device *dev, switch (type) { case DEV_PM_QOS_RESUME_LATENCY: ret = blocking_notifier_chain_unregister(dev->power.qos->resume_latency.notifiers, notifier); break;

• case DEV_PM_QOS_MIN_FREQUENCY:

• ret = freq_qos_remove_notifier(&dev->power.qos->freq,
  

• 			       FREQ_QOS_MIN, notifier);
  

• break;
  

• case DEV_PM_QOS_MAX_FREQUENCY:

• ret = freq_qos_remove_notifier(&dev->power.qos->freq,
  

• 			       FREQ_QOS_MAX, notifier);
  

• break;
  

  default: WARN_ON(1); ret = -EINVAL; }

diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h index 678fec6da5b9..19eafca5680e 100644 --- a/include/linux/pm_qos.h +++ b/include/linux/pm_qos.h @@ -32,10 +32,12 @@ enum pm_qos_flags_status { #define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC) #define PM_QOS_RESUME_LATENCY_DEFAULT_VALUE PM_QOS_LATENCY_ANY #define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT PM_QOS_LATENCY_ANY #define PM_QOS_RESUME_LATENCY_NO_CONSTRAINT_NS PM_QOS_LATENCY_ANY_NS #define PM_QOS_LATENCY_TOLERANCE_DEFAULT_VALUE 0 +#define PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE 0 +#define PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE FREQ_QOS_MAX_DEFAULT_VALUE #define PM_QOS_LATENCY_TOLERANCE_NO_CONSTRAINT (-1) #define PM_QOS_FLAG_NO_POWER_OFF (1 << 0) struct pm_qos_request { @@ -99,25 +101,29 @@ struct freq_qos_request { enum dev_pm_qos_req_type { DEV_PM_QOS_RESUME_LATENCY = 1, DEV_PM_QOS_LATENCY_TOLERANCE,

• DEV_PM_QOS_MIN_FREQUENCY,
• DEV_PM_QOS_MAX_FREQUENCY, DEV_PM_QOS_FLAGS, };

struct dev_pm_qos_request { enum dev_pm_qos_req_type type; union { struct plist_node pnode; struct pm_qos_flags_request flr;

• struct freq_qos_request freq;
  

  } data; struct device *dev; };

struct dev_pm_qos { struct pm_qos_constraints resume_latency; struct pm_qos_constraints latency_tolerance;

• struct freq_constraints freq; struct pm_qos_flags flags; struct dev_pm_qos_request *resume_latency_req; struct dev_pm_qos_request *latency_tolerance_req; struct dev_pm_qos_request *flags_req; };

@@ -212,10 +218,14 @@ static inline s32 dev_pm_qos_read_value(struct device *dev, enum dev_pm_qos_req_type type) { switch (type) { case DEV_PM_QOS_RESUME_LATENCY: return PM_QOS_RESUME_LATENCY_NO_CONSTRAINT;

• case DEV_PM_QOS_MIN_FREQUENCY:

• return PM_QOS_MIN_FREQUENCY_DEFAULT_VALUE;
  

• case DEV_PM_QOS_MAX_FREQUENCY:

• return PM_QOS_MAX_FREQUENCY_DEFAULT_VALUE;
  

  default: WARN_ON(1); return 0; } }

@@ -291,10 +301,12 @@ s32 freq_qos_read_value(struct freq_constraints *qos, int freq_qos_add_request(struct freq_constraints *qos, struct freq_qos_request *req, enum freq_qos_req_type type, s32 value); int freq_qos_update_request(struct freq_qos_request *req, s32 new_value); int freq_qos_remove_request(struct freq_qos_request *req); +int freq_qos_apply(struct freq_qos_request *req,

•    enum pm_qos_req_action action, s32 value);
  

int freq_qos_add_notifier(struct freq_constraints *qos, enum freq_qos_req_type type, struct notifier_block *notifier); int freq_qos_remove_notifier(struct freq_constraints *qos, diff --git a/kernel/power/qos.c b/kernel/power/qos.c index a45cba7df0ae..83edf8698118 100644 --- a/kernel/power/qos.c +++ b/kernel/power/qos.c @@ -712,12 +712,14 @@ s32 freq_qos_read_value(struct freq_constraints *qos, /**

• freq_qos_apply - Add/modify/remove frequency QoS request.
• @req: Constraint request to apply.
• @action: Action to perform (add/update/remove).
• @value: Value to assign to the QoS request.

• • This is only meant to be called from inside pm_qos, not drivers.
  */

-static int freq_qos_apply(struct freq_qos_request *req, +int freq_qos_apply(struct freq_qos_request *req, enum pm_qos_req_action action, s32 value) { int ret; switch(req->type) {

Reviewed-by: Matthias Kaehlcke mka@chromium.org Tested-by: Matthias Kaehlcke mka@chromium.org

Thanks for taking the time to look into this.