[RFC PATCH] PM: QoS: Get rid of unused flags

From: Amit Kucheria
Date: Wed Jul 10 2019 - 06:12:39 EST


The network_latency and network_throughput flags for PM-QoS have not
found much use in drivers or in userspace since they were introduced.

Commit 4a733ef1bea7 ("mac80211: remove PM-QoS listener") removed the
only user PM_QOS_NETWORK_LATENCY in the kernel a while ago and there
don't seem to be any userspace tools using the character device files
either.

PM_QOS_MEMORY_BANDWIDTH was never even added to the trace events.

Remove all the flags except cpu_dma_latency.

Signed-off-by: Amit Kucheria <amit.kucheria@xxxxxxxxxx>
---
I've looked around for use of /dev/network_throughput and
/dev/network_bandwidth) and not found any userspace programs that seem to
use this currently. So this shouldn't be breaking our ABI contract with
userspace.

Documentation/power/pm_qos_interface.txt | 5 +--
include/linux/pm_qos.h | 6 ---
include/trace/events/power.h | 8 +---
kernel/power/qos.c | 48 ------------------------
4 files changed, 4 insertions(+), 63 deletions(-)

diff --git a/Documentation/power/pm_qos_interface.txt b/Documentation/power/pm_qos_interface.txt
index 19c5f7b1a7bab..ac53ca4ae24e1 100644
--- a/Documentation/power/pm_qos_interface.txt
+++ b/Documentation/power/pm_qos_interface.txt
@@ -5,8 +5,7 @@ performance expectations by drivers, subsystems and user space applications on
one of the parameters.

Two different PM QoS frameworks are available:
-1. PM QoS classes for cpu_dma_latency, network_latency, network_throughput,
-memory_bandwidth.
+1. PM QoS classes for cpu_dma_latency
2. the per-device PM QoS framework provides the API to manage the per-device latency
constraints and PM QoS flags.

@@ -74,7 +73,7 @@ cleanup of a process, the interface requires the process to register its
parameter requests in the following way:

To register the default pm_qos target for the specific parameter, the process
-must open one of /dev/[cpu_dma_latency, network_latency, network_throughput]
+must open /dev/cpu_dma_latency

As long as the device node is held open that process has a registered
request on the parameter.
diff --git a/include/linux/pm_qos.h b/include/linux/pm_qos.h
index 6ea1ae373d77c..2a3c237b1910d 100644
--- a/include/linux/pm_qos.h
+++ b/include/linux/pm_qos.h
@@ -13,9 +13,6 @@
enum {
PM_QOS_RESERVED = 0,
PM_QOS_CPU_DMA_LATENCY,
- PM_QOS_NETWORK_LATENCY,
- PM_QOS_NETWORK_THROUGHPUT,
- PM_QOS_MEMORY_BANDWIDTH,

/* insert new class ID */
PM_QOS_NUM_CLASSES,
@@ -33,9 +30,6 @@ enum pm_qos_flags_status {
#define PM_QOS_LATENCY_ANY_NS ((s64)PM_QOS_LATENCY_ANY * NSEC_PER_USEC)

#define PM_QOS_CPU_DMA_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
-#define PM_QOS_NETWORK_LAT_DEFAULT_VALUE (2000 * USEC_PER_SEC)
-#define PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE 0
-#define PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE 0
#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
diff --git a/include/trace/events/power.h b/include/trace/events/power.h
index f7aece721aed7..7457e238e1b74 100644
--- a/include/trace/events/power.h
+++ b/include/trace/events/power.h
@@ -379,9 +379,7 @@ DECLARE_EVENT_CLASS(pm_qos_request,

TP_printk("pm_qos_class=%s value=%d",
__print_symbolic(__entry->pm_qos_class,
- { PM_QOS_CPU_DMA_LATENCY, "CPU_DMA_LATENCY" },
- { PM_QOS_NETWORK_LATENCY, "NETWORK_LATENCY" },
- { PM_QOS_NETWORK_THROUGHPUT, "NETWORK_THROUGHPUT" }),
+ { PM_QOS_CPU_DMA_LATENCY, "CPU_DMA_LATENCY" }),
__entry->value)
);

@@ -426,9 +424,7 @@ TRACE_EVENT(pm_qos_update_request_timeout,

TP_printk("pm_qos_class=%s value=%d, timeout_us=%ld",
__print_symbolic(__entry->pm_qos_class,
- { PM_QOS_CPU_DMA_LATENCY, "CPU_DMA_LATENCY" },
- { PM_QOS_NETWORK_LATENCY, "NETWORK_LATENCY" },
- { PM_QOS_NETWORK_THROUGHPUT, "NETWORK_THROUGHPUT" }),
+ { PM_QOS_CPU_DMA_LATENCY, "CPU_DMA_LATENCY" }),
__entry->value, __entry->timeout_us)
);

diff --git a/kernel/power/qos.c b/kernel/power/qos.c
index 33e3febaba53f..9568a2fe7c116 100644
--- a/kernel/power/qos.c
+++ b/kernel/power/qos.c
@@ -78,57 +78,9 @@ static struct pm_qos_object cpu_dma_pm_qos = {
.name = "cpu_dma_latency",
};

-static BLOCKING_NOTIFIER_HEAD(network_lat_notifier);
-static struct pm_qos_constraints network_lat_constraints = {
- .list = PLIST_HEAD_INIT(network_lat_constraints.list),
- .target_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
- .default_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
- .no_constraint_value = PM_QOS_NETWORK_LAT_DEFAULT_VALUE,
- .type = PM_QOS_MIN,
- .notifiers = &network_lat_notifier,
-};
-static struct pm_qos_object network_lat_pm_qos = {
- .constraints = &network_lat_constraints,
- .name = "network_latency",
-};
-
-
-static BLOCKING_NOTIFIER_HEAD(network_throughput_notifier);
-static struct pm_qos_constraints network_tput_constraints = {
- .list = PLIST_HEAD_INIT(network_tput_constraints.list),
- .target_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
- .default_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
- .no_constraint_value = PM_QOS_NETWORK_THROUGHPUT_DEFAULT_VALUE,
- .type = PM_QOS_MAX,
- .notifiers = &network_throughput_notifier,
-};
-static struct pm_qos_object network_throughput_pm_qos = {
- .constraints = &network_tput_constraints,
- .name = "network_throughput",
-};
-
-
-static BLOCKING_NOTIFIER_HEAD(memory_bandwidth_notifier);
-static struct pm_qos_constraints memory_bw_constraints = {
- .list = PLIST_HEAD_INIT(memory_bw_constraints.list),
- .target_value = PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE,
- .default_value = PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE,
- .no_constraint_value = PM_QOS_MEMORY_BANDWIDTH_DEFAULT_VALUE,
- .type = PM_QOS_SUM,
- .notifiers = &memory_bandwidth_notifier,
-};
-static struct pm_qos_object memory_bandwidth_pm_qos = {
- .constraints = &memory_bw_constraints,
- .name = "memory_bandwidth",
-};
-
-
static struct pm_qos_object *pm_qos_array[] = {
&null_pm_qos,
&cpu_dma_pm_qos,
- &network_lat_pm_qos,
- &network_throughput_pm_qos,
- &memory_bandwidth_pm_qos,
};

static ssize_t pm_qos_power_write(struct file *filp, const char __user *buf,
--
2.17.1