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Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Browse Source 
Pull scheduler updates from Ingo Molnar:
 "The main changes in this cycle were:

   - refcount conversions

   - Solve the rq->leaf_cfs_rq_list can of worms for real.

   - improve power-aware scheduling

   - add sysctl knob for Energy Aware Scheduling

   - documentation updates

   - misc other changes"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (34 commits)
  kthread: Do not use TIMER_IRQSAFE
  kthread: Convert worker lock to raw spinlock
  sched/fair: Use non-atomic cpumask_{set,clear}_cpu()
  sched/fair: Remove unused 'sd' parameter from select_idle_smt()
  sched/wait: Use freezable_schedule() when possible
  sched/fair: Prune, fix and simplify the nohz_balancer_kick() comment block
  sched/fair: Explain LLC nohz kick condition
  sched/fair: Simplify nohz_balancer_kick()
  sched/topology: Fix percpu data types in struct sd_data & struct s_data
  sched/fair: Simplify post_init_entity_util_avg() by calling it with a task_struct pointer argument
  sched/fair: Fix O(nr_cgroups) in the load balancing path
  sched/fair: Optimize update_blocked_averages()
  sched/fair: Fix insertion in rq->leaf_cfs_rq_list
  sched/fair: Add tmp_alone_branch assertion
  sched/core: Use READ_ONCE()/WRITE_ONCE() in move_queued_task()/task_rq_lock()
  sched/debug: Initialize sd_sysctl_cpus if !CONFIG_CPUMASK_OFFSTACK
  sched/pelt: Skip updating util_est when utilization is higher than CPU's capacity
  sched/fair: Update scale invariance of PELT
  sched/fair: Move the rq_of() helper function
  sched/core: Convert task_struct.stack_refcount to refcount_t
  ...
This commit is contained in:
Linus Torvalds 2019-03-06 08:14:05 -08:00
commit 45802da05e
29 changed files with 1169 additions and 328 deletions
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144
Documentation/power/energy-model.txt Normal file
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====================
Energy Model of CPUs
====================
1. Overview
-----------
The Energy Model (EM) framework serves as an interface between drivers knowing
the power consumed by CPUs at various performance levels, and the kernel
subsystems willing to use that information to make energy-aware decisions.
The source of the information about the power consumed by CPUs can vary greatly
from one platform to another. These power costs can be estimated using
devicetree data in some cases. In others, the firmware will know better.
Alternatively, userspace might be best positioned. And so on. In order to avoid
each and every client subsystem to re-implement support for each and every
possible source of information on its own, the EM framework intervenes as an
abstraction layer which standardizes the format of power cost tables in the
kernel, hence enabling to avoid redundant work.
The figure below depicts an example of drivers (Arm-specific here, but the
approach is applicable to any architecture) providing power costs to the EM
framework, and interested clients reading the data from it.
+---------------+ +-----------------+ +---------------+
| Thermal (IPA) | | Scheduler (EAS) | | Other |
+---------------+ +-----------------+ +---------------+
| | em_pd_energy() |
| | em_cpu_get() |
+---------+ | +---------+
| | |
v v v
+---------------------+
| Energy Model |
| Framework |
+---------------------+
^ ^ ^
| | | em_register_perf_domain()
+----------+ | +---------+
| | |
+---------------+ +---------------+ +--------------+
| cpufreq-dt | | arm_scmi | | Other |
+---------------+ +---------------+ +--------------+
^ ^ ^
| | |
+--------------+ +---------------+ +--------------+
| Device Tree | | Firmware | | ? |
+--------------+ +---------------+ +--------------+
The EM framework manages power cost tables per 'performance domain' in the
system. A performance domain is a group of CPUs whose performance is scaled
together. Performance domains generally have a 1-to-1 mapping with CPUFreq
policies. All CPUs in a performance domain are required to have the same
micro-architecture. CPUs in different performance domains can have different
micro-architectures.
2. Core APIs
------------
2.1 Config options
CONFIG_ENERGY_MODEL must be enabled to use the EM framework.
2.2 Registration of performance domains
Drivers are expected to register performance domains into the EM framework by
calling the following API:
int em_register_perf_domain(cpumask_t *span, unsigned int nr_states,
struct em_data_callback *cb);
Drivers must specify the CPUs of the performance domains using the cpumask
argument, and provide a callback function returning <frequency, power> tuples
for each capacity state. The callback function provided by the driver is free
to fetch data from any relevant location (DT, firmware, ...), and by any mean
deemed necessary. See Section 3. for an example of driver implementing this
callback, and kernel/power/energy_model.c for further documentation on this
API.
2.3 Accessing performance domains
Subsystems interested in the energy model of a CPU can retrieve it using the
em_cpu_get() API. The energy model tables are allocated once upon creation of
the performance domains, and kept in memory untouched.
The energy consumed by a performance domain can be estimated using the
em_pd_energy() API. The estimation is performed assuming that the schedutil
CPUfreq governor is in use.
More details about the above APIs can be found in include/linux/energy_model.h.
3. Example driver
-----------------
This section provides a simple example of a CPUFreq driver registering a
performance domain in the Energy Model framework using the (fake) 'foo'
protocol. The driver implements an est_power() function to be provided to the
EM framework.
-> drivers/cpufreq/foo_cpufreq.c
01 static int est_power(unsigned long *mW, unsigned long *KHz, int cpu)
02 {
03 long freq, power;
04
05 /* Use the 'foo' protocol to ceil the frequency */
06 freq = foo_get_freq_ceil(cpu, *KHz);
07 if (freq < 0);
08 return freq;
09
10 /* Estimate the power cost for the CPU at the relevant freq. */
11 power = foo_estimate_power(cpu, freq);
12 if (power < 0);
13 return power;
14
15 /* Return the values to the EM framework */
16 *mW = power;
17 *KHz = freq;
18
19 return 0;
20 }
21
22 static int foo_cpufreq_init(struct cpufreq_policy *policy)
23 {
24 struct em_data_callback em_cb = EM_DATA_CB(est_power);
25 int nr_opp, ret;
26
27 /* Do the actual CPUFreq init work ... */
28 ret = do_foo_cpufreq_init(policy);
29 if (ret)
30 return ret;
31
32 /* Find the number of OPPs for this policy */
33 nr_opp = foo_get_nr_opp(policy);
34
35 /* And register the new performance domain */
36 em_register_perf_domain(policy->cpus, nr_opp, &em_cb);
37
38 return 0;
39 }

425
Documentation/scheduler/sched-energy.txt Normal file
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=======================
Energy Aware Scheduling
=======================
1. Introduction
---------------
Energy Aware Scheduling (or EAS) gives the scheduler the ability to predict
the impact of its decisions on the energy consumed by CPUs. EAS relies on an
Energy Model (EM) of the CPUs to select an energy efficient CPU for each task,
with a minimal impact on throughput. This document aims at providing an
introduction on how EAS works, what are the main design decisions behind it, and
details what is needed to get it to run.
Before going any further, please note that at the time of writing:
/!\ EAS does not support platforms with symmetric CPU topologies /!\
EAS operates only on heterogeneous CPU topologies (such as Arm big.LITTLE)
because this is where the potential for saving energy through scheduling is
the highest.
The actual EM used by EAS is _not_ maintained by the scheduler, but by a
dedicated framework. For details about this framework and what it provides,
please refer to its documentation (see Documentation/power/energy-model.txt).
2. Background and Terminology
-----------------------------
To make it clear from the start:
- energy = [joule] (resource like a battery on powered devices)
- power = energy/time = [joule/second] = [watt]
The goal of EAS is to minimize energy, while still getting the job done. That
is, we want to maximize:
performance [inst/s]
--------------------
power [W]
which is equivalent to minimizing:
energy [J]
-----------
instruction
while still getting 'good' performance. It is essentially an alternative
optimization objective to the current performance-only objective for the
scheduler. This alternative considers two objectives: energy-efficiency and
performance.
The idea behind introducing an EM is to allow the scheduler to evaluate the
implications of its decisions rather than blindly applying energy-saving
techniques that may have positive effects only on some platforms. At the same
time, the EM must be as simple as possible to minimize the scheduler latency
impact.
In short, EAS changes the way CFS tasks are assigned to CPUs. When it is time
for the scheduler to decide where a task should run (during wake-up), the EM
is used to break the tie between several good CPU candidates and pick the one
that is predicted to yield the best energy consumption without harming the
system's throughput. The predictions made by EAS rely on specific elements of
knowledge about the platform's topology, which include the 'capacity' of CPUs,
and their respective energy costs.
3. Topology information
-----------------------
EAS (as well as the rest of the scheduler) uses the notion of 'capacity' to
differentiate CPUs with different computing throughput. The 'capacity' of a CPU
represents the amount of work it can absorb when running at its highest
frequency compared to the most capable CPU of the system. Capacity values are
normalized in a 1024 range, and are comparable with the utilization signals of
tasks and CPUs computed by the Per-Entity Load Tracking (PELT) mechanism. Thanks
to capacity and utilization values, EAS is able to estimate how big/busy a
task/CPU is, and to take this into consideration when evaluating performance vs
energy trade-offs. The capacity of CPUs is provided via arch-specific code
through the arch_scale_cpu_capacity() callback.
The rest of platform knowledge used by EAS is directly read from the Energy
Model (EM) framework. The EM of a platform is composed of a power cost table
per 'performance domain' in the system (see Documentation/power/energy-model.txt
for futher details about performance domains).
The scheduler manages references to the EM objects in the topology code when the
scheduling domains are built, or re-built. For each root domain (rd), the
scheduler maintains a singly linked list of all performance domains intersecting
the current rd->span. Each node in the list contains a pointer to a struct
em_perf_domain as provided by the EM framework.
The lists are attached to the root domains in order to cope with exclusive
cpuset configurations. Since the boundaries of exclusive cpusets do not
necessarily match those of performance domains, the lists of different root
domains can contain duplicate elements.
Example 1.
Let us consider a platform with 12 CPUs, split in 3 performance domains
(pd0, pd4 and pd8), organized as follows:
CPUs: 0 1 2 3 4 5 6 7 8 9 10 11
PDs: |--pd0--|--pd4--|---pd8---|
RDs: |----rd1----|-----rd2-----|
Now, consider that userspace decided to split the system with two
exclusive cpusets, hence creating two independent root domains, each
containing 6 CPUs. The two root domains are denoted rd1 and rd2 in the
above figure. Since pd4 intersects with both rd1 and rd2, it will be
present in the linked list '->pd' attached to each of them:
* rd1->pd: pd0 -> pd4
* rd2->pd: pd4 -> pd8
Please note that the scheduler will create two duplicate list nodes for
pd4 (one for each list). However, both just hold a pointer to the same
shared data structure of the EM framework.
Since the access to these lists can happen concurrently with hotplug and other
things, they are protected by RCU, like the rest of topology structures
manipulated by the scheduler.
EAS also maintains a static key (sched_energy_present) which is enabled when at
least one root domain meets all conditions for EAS to start. Those conditions
are summarized in Section 6.
4. Energy-Aware task placement
------------------------------
EAS overrides the CFS task wake-up balancing code. It uses the EM of the
platform and the PELT signals to choose an energy-efficient target CPU during
wake-up balance. When EAS is enabled, select_task_rq_fair() calls
find_energy_efficient_cpu() to do the placement decision. This function looks
for the CPU with the highest spare capacity (CPU capacity - CPU utilization) in
each performance domain since it is the one which will allow us to keep the
frequency the lowest. Then, the function checks if placing the task there could
save energy compared to leaving it on prev_cpu, i.e. the CPU where the task ran
in its previous activation.
find_energy_efficient_cpu() uses compute_energy() to estimate what will be the
energy consumed by the system if the waking task was migrated. compute_energy()
looks at the current utilization landscape of the CPUs and adjusts it to
'simulate' the task migration. The EM framework provides the em_pd_energy() API
which computes the expected energy consumption of each performance domain for
the given utilization landscape.
An example of energy-optimized task placement decision is detailed below.
Example 2.
Let us consider a (fake) platform with 2 independent performance domains
composed of two CPUs each. CPU0 and CPU1 are little CPUs; CPU2 and CPU3
are big.
The scheduler must decide where to place a task P whose util_avg = 200
and prev_cpu = 0.
The current utilization landscape of the CPUs is depicted on the graph
below. CPUs 0-3 have a util_avg of 400, 100, 600 and 500 respectively
Each performance domain has three Operating Performance Points (OPPs).
The CPU capacity and power cost associated with each OPP is listed in
the Energy Model table. The util_avg of P is shown on the figures
below as 'PP'.
CPU util.
1024 - - - - - - - Energy Model
+-----------+-------------+
| Little | Big |
768 ============= +-----+-----+------+------+
| Cap | Pwr | Cap | Pwr |
+-----+-----+------+------+
512 =========== - ##- - - - - | 170 | 50 | 512 | 400 |
## ## | 341 | 150 | 768 | 800 |
341 -PP - - - - ## ## | 512 | 300 | 1024 | 1700 |
PP ## ## +-----+-----+------+------+
170 -## - - - - ## ##
## ## ## ##
------------ -------------
CPU0 CPU1 CPU2 CPU3
Current OPP: ===== Other OPP: - - - util_avg (100 each): ##
find_energy_efficient_cpu() will first look for the CPUs with the
maximum spare capacity in the two performance domains. In this example,
CPU1 and CPU3. Then it will estimate the energy of the system if P was
placed on either of them, and check if that would save some energy
compared to leaving P on CPU0. EAS assumes that OPPs follow utilization
(which is coherent with the behaviour of the schedutil CPUFreq
governor, see Section 6. for more details on this topic).
Case 1. P is migrated to CPU1
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1024 - - - - - - -
Energy calculation:
768 ============= * CPU0: 200 / 341 * 150 = 88
* CPU1: 300 / 341 * 150 = 131
* CPU2: 600 / 768 * 800 = 625
512 - - - - - - - ##- - - - - * CPU3: 500 / 768 * 800 = 520
## ## => total_energy = 1364
341 =========== ## ##
PP ## ##
170 -## - - PP- ## ##
## ## ## ##
------------ -------------
CPU0 CPU1 CPU2 CPU3
Case 2. P is migrated to CPU3
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1024 - - - - - - -
Energy calculation:
768 ============= * CPU0: 200 / 341 * 150 = 88
* CPU1: 100 / 341 * 150 = 43
PP * CPU2: 600 / 768 * 800 = 625
512 - - - - - - - ##- - -PP - * CPU3: 700 / 768 * 800 = 729
## ## => total_energy = 1485
341 =========== ## ##
## ##
170 -## - - - - ## ##
## ## ## ##
------------ -------------
CPU0 CPU1 CPU2 CPU3
Case 3. P stays on prev_cpu / CPU 0
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1024 - - - - - - -
Energy calculation:
768 ============= * CPU0: 400 / 512 * 300 = 234
* CPU1: 100 / 512 * 300 = 58
* CPU2: 600 / 768 * 800 = 625
512 =========== - ##- - - - - * CPU3: 500 / 768 * 800 = 520
## ## => total_energy = 1437
341 -PP - - - - ## ##
PP ## ##
170 -## - - - - ## ##
## ## ## ##
------------ -------------
CPU0 CPU1 CPU2 CPU3
From these calculations, the Case 1 has the lowest total energy. So CPU 1
is be the best candidate from an energy-efficiency standpoint.
Big CPUs are generally more power hungry than the little ones and are thus used
mainly when a task doesn't fit the littles. However, little CPUs aren't always
necessarily more energy-efficient than big CPUs. For some systems, the high OPPs
of the little CPUs can be less energy-efficient than the lowest OPPs of the
bigs, for example. So, if the little CPUs happen to have enough utilization at
a specific point in time, a small task waking up at that moment could be better
of executing on the big side in order to save energy, even though it would fit
on the little side.
And even in the case where all OPPs of the big CPUs are less energy-efficient
than those of the little, using the big CPUs for a small task might still, under
specific conditions, save energy. Indeed, placing a task on a little CPU can
result in raising the OPP of the entire performance domain, and that will
increase the cost of the tasks already running there. If the waking task is
placed on a big CPU, its own execution cost might be higher than if it was
running on a little, but it won't impact the other tasks of the little CPUs
which will keep running at a lower OPP. So, when considering the total energy
consumed by CPUs, the extra cost of running that one task on a big core can be
smaller than the cost of raising the OPP on the little CPUs for all the other
tasks.
The examples above would be nearly impossible to get right in a generic way, and
for all platforms, without knowing the cost of running at different OPPs on all
CPUs of the system. Thanks to its EM-based design, EAS should cope with them
correctly without too many troubles. However, in order to ensure a minimal
impact on throughput for high-utilization scenarios, EAS also implements another
mechanism called 'over-utilization'.
5. Over-utilization
-------------------
From a general standpoint, the use-cases where EAS can help the most are those
involving a light/medium CPU utilization. Whenever long CPU-bound tasks are
being run, they will require all of the available CPU capacity, and there isn't
much that can be done by the scheduler to save energy without severly harming
throughput. In order to avoid hurting performance with EAS, CPUs are flagged as
'over-utilized' as soon as they are used at more than 80% of their compute
capacity. As long as no CPUs are over-utilized in a root domain, load balancing
is disabled and EAS overridess the wake-up balancing code. EAS is likely to load
the most energy efficient CPUs of the system more than the others if that can be
done without harming throughput. So, the load-balancer is disabled to prevent
it from breaking the energy-efficient task placement found by EAS. It is safe to
do so when the system isn't overutilized since being below the 80% tipping point
implies that:
a. there is some idle time on all CPUs, so the utilization signals used by
EAS are likely to accurately represent the 'size' of the various tasks
in the system;
b. all tasks should already be provided with enough CPU capacity,
regardless of their nice values;
c. since there is spare capacity all tasks must be blocking/sleeping
regularly and balancing at wake-up is sufficient.
As soon as one CPU goes above the 80% tipping point, at least one of the three
assumptions above becomes incorrect. In this scenario, the 'overutilized' flag
is raised for the entire root domain, EAS is disabled, and the load-balancer is
re-enabled. By doing so, the scheduler falls back onto load-based algorithms for
wake-up and load balance under CPU-bound conditions. This provides a better
respect of the nice values of tasks.
Since the notion of overutilization largely relies on detecting whether or not
there is some idle time in the system, the CPU capacity 'stolen' by higher
(than CFS) scheduling classes (as well as IRQ) must be taken into account. As
such, the detection of overutilization accounts for the capacity used not only
by CFS tasks, but also by the other scheduling classes and IRQ.
6. Dependencies and requirements for EAS
----------------------------------------
Energy Aware Scheduling depends on the CPUs of the system having specific
hardware properties and on other features of the kernel being enabled. This
section lists these dependencies and provides hints as to how they can be met.
6.1 - Asymmetric CPU topology
As mentioned in the introduction, EAS is only supported on platforms with
asymmetric CPU topologies for now. This requirement is checked at run-time by
looking for the presence of the SD_ASYM_CPUCAPACITY flag when the scheduling
domains are built.
The flag is set/cleared automatically by the scheduler topology code whenever
there are CPUs with different capacities in a root domain. The capacities of
CPUs are provided by arch-specific code through the arch_scale_cpu_capacity()
callback. As an example, arm and arm64 share an implementation of this callback
which uses a combination of CPUFreq data and device-tree bindings to compute the
capacity of CPUs (see drivers/base/arch_topology.c for more details).
So, in order to use EAS on your platform your architecture must implement the
arch_scale_cpu_capacity() callback, and some of the CPUs must have a lower
capacity than others.
Please note that EAS is not fundamentally incompatible with SMP, but no
significant savings on SMP platforms have been observed yet. This restriction
could be amended in the future if proven otherwise.
6.2 - Energy Model presence
EAS uses the EM of a platform to estimate the impact of scheduling decisions on
energy. So, your platform must provide power cost tables to the EM framework in
order to make EAS start. To do so, please refer to documentation of the
independent EM framework in Documentation/power/energy-model.txt.
Please also note that the scheduling domains need to be re-built after the
EM has been registered in order to start EAS.
6.3 - Energy Model complexity
The task wake-up path is very latency-sensitive. When the EM of a platform is
too complex (too many CPUs, too many performance domains, too many performance
states, ...), the cost of using it in the wake-up path can become prohibitive.
The energy-aware wake-up algorithm has a complexity of:
C = Nd * (Nc + Ns)
with: Nd the number of performance domains; Nc the number of CPUs; and Ns the
total number of OPPs (ex: for two perf. domains with 4 OPPs each, Ns = 8).
A complexity check is performed at the root domain level, when scheduling
domains are built. EAS will not start on a root domain if its C happens to be
higher than the completely arbitrary EM_MAX_COMPLEXITY threshold (2048 at the
time of writing).
If you really want to use EAS but the complexity of your platform's Energy
Model is too high to be used with a single root domain, you're left with only
two possible options:
1. split your system into separate, smaller, root domains using exclusive
cpusets and enable EAS locally on each of them. This option has the
benefit to work out of the box but the drawback of preventing load
balance between root domains, which can result in an unbalanced system
overall;
2. submit patches to reduce the complexity of the EAS wake-up algorithm,
hence enabling it to cope with larger EMs in reasonable time.
6.4 - Schedutil governor
EAS tries to predict at which OPP will the CPUs be running in the close future
in order to estimate their energy consumption. To do so, it is assumed that OPPs
of CPUs follow their utilization.
Although it is very difficult to provide hard guarantees regarding the accuracy
of this assumption in practice (because the hardware might not do what it is
told to do, for example), schedutil as opposed to other CPUFreq governors at
least _requests_ frequencies calculated using the utilization signals.
Consequently, the only sane governor to use together with EAS is schedutil,
because it is the only one providing some degree of consistency between
frequency requests and energy predictions.
Using EAS with any other governor than schedutil is not supported.
6.5 Scale-invariant utilization signals
In order to make accurate prediction across CPUs and for all performance
states, EAS needs frequency-invariant and CPU-invariant PELT signals. These can
be obtained using the architecture-defined arch_scale{cpu,freq}_capacity()
callbacks.
Using EAS on a platform that doesn't implement these two callbacks is not
supported.
6.6 Multithreading (SMT)
EAS in its current form is SMT unaware and is not able to leverage
multithreaded hardware to save energy. EAS considers threads as independent
CPUs, which can actually be counter-productive for both performance and energy.
EAS on SMT is not supported.

12
Documentation/sysctl/kernel.txt
View File

@ -79,6 +79,7 @@ show up in /proc/sys/kernel:
- reboot-cmd [ SPARC only ]
- rtsig-max
- rtsig-nr
- sched_energy_aware
- seccomp/ ==> Documentation/userspace-api/seccomp_filter.rst
- sem
- sem_next_id [ sysv ipc ]
@ -890,6 +891,17 @@ rtsig-nr shows the number of RT signals currently queued.
==============================================================
sched_energy_aware:
Enables/disables Energy Aware Scheduling (EAS). EAS starts
automatically on platforms where it can run (that is,
platforms with asymmetric CPU topologies and having an Energy
Model available). If your platform happens to meet the
requirements for EAS but you do not want to use it, change
this value to 0.
==============================================================
sched_schedstats:
Enables/disables scheduler statistics. Enabling this feature

9
MAINTAINERS
View File

@ -12280,14 +12280,6 @@ S: Maintained
F: drivers/net/ppp/pptp.c
W: http://sourceforge.net/projects/accel-pptp
PREEMPTIBLE KERNEL
M: Robert Love <rml@tech9.net>
L: kpreempt-tech@lists.sourceforge.net
W: https://www.kernel.org/pub/linux/kernel/people/rml/preempt-kernel
S: Supported
F: Documentation/preempt-locking.txt
F: include/linux/preempt.h
PRINTK
M: Petr Mladek <pmladek@suse.com>
M: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
@ -13525,6 +13517,7 @@ F: kernel/sched/
F: include/linux/sched.h
F: include/uapi/linux/sched.h
F: include/linux/wait.h
F: include/linux/preempt.h
SCR24X CHIP CARD INTERFACE DRIVER
M: Lubomir Rintel <lkundrak@v3.sk>

4
fs/exec.c
View File

@ -1189,7 +1189,7 @@ no_thread_group:
flush_itimer_signals();
#endif
if (atomic_read(&oldsighand->count) != 1) {
if (refcount_read(&oldsighand->count) != 1) {
struct sighand_struct *newsighand;
/*
* This ->sighand is shared with the CLONE_SIGHAND
@ -1199,7 +1199,7 @@ no_thread_group:
if (!newsighand)
return -ENOMEM;
atomic_set(&newsighand->count, 1);
refcount_set(&newsighand->count, 1);
memcpy(newsighand->action, oldsighand->action,
sizeof(newsighand->action));

2
fs/proc/task_nommu.c
View File

@ -64,7 +64,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
else
bytes += kobjsize(current->files);
if (current->sighand && atomic_read(&current->sighand->count) > 1)
if (current->sighand && refcount_read(&current->sighand->count) > 1)
sbytes += kobjsize(current->sighand);
else
bytes += kobjsize(current->sighand);

1
include/linux/init_task.h
View File

@ -13,6 +13,7 @@
#include <linux/securebits.h>
#include <linux/seqlock.h>
#include <linux/rbtree.h>
#include <linux/refcount.h>
#include <linux/sched/autogroup.h>
#include <net/net_namespace.h>
#include <linux/sched/rt.h>

9
include/linux/kthread.h
View File

@ -86,7 +86,7 @@ enum {
struct kthread_worker {
unsigned int flags;
spinlock_t lock;
raw_spinlock_t lock;
struct list_head work_list;
struct list_head delayed_work_list;
struct task_struct *task;
@ -107,7 +107,7 @@ struct kthread_delayed_work {
};
#define KTHREAD_WORKER_INIT(worker) { \
.lock = __SPIN_LOCK_UNLOCKED((worker).lock), \
.lock = __RAW_SPIN_LOCK_UNLOCKED((worker).lock), \
.work_list = LIST_HEAD_INIT((worker).work_list), \
.delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\
}
@ -165,9 +165,8 @@ extern void __kthread_init_worker(struct kthread_worker *worker,
#define kthread_init_delayed_work(dwork, fn) \
do { \
kthread_init_work(&(dwork)->work, (fn)); \
__init_timer(&(dwork)->timer, \
kthread_delayed_work_timer_fn, \
TIMER_IRQSAFE); \
timer_setup(&(dwork)->timer, \
kthread_delayed_work_timer_fn, 0); \
} while (0)
int kthread_worker_fn(void *worker_ptr);

33
include/linux/sched.h
View File

@ -21,6 +21,7 @@
#include <linux/seccomp.h>
#include <linux/nodemask.h>
#include <linux/rcupdate.h>
#include <linux/refcount.h>
#include <linux/resource.h>
#include <linux/latencytop.h>
#include <linux/sched/prio.h>
@ -356,12 +357,6 @@ struct util_est {
* For cfs_rq, it is the aggregated load_avg of all runnable and
* blocked sched_entities.
*
* load_avg may also take frequency scaling into account:
*
* load_avg = runnable% * scale_load_down(load) * freq%
*
* where freq% is the CPU frequency normalized to the highest frequency.
*
* [util_avg definition]
*
* util_avg = running% * SCHED_CAPACITY_SCALE
@ -370,17 +365,14 @@ struct util_est {
* a CPU. For cfs_rq, it is the aggregated util_avg of all runnable
* and blocked sched_entities.
*
* util_avg may also factor frequency scaling and CPU capacity scaling:
* load_avg and util_avg don't direcly factor frequency scaling and CPU
* capacity scaling. The scaling is done through the rq_clock_pelt that
* is used for computing those signals (see update_rq_clock_pelt())
*
* util_avg = running% * SCHED_CAPACITY_SCALE * freq% * capacity%
*
* where freq% is the same as above, and capacity% is the CPU capacity
* normalized to the greatest capacity (due to uarch differences, etc).
*
* N.B., the above ratios (runnable%, running%, freq%, and capacity%)
* themselves are in the range of [0, 1]. To do fixed point arithmetics,
* we therefore scale them to as large a range as necessary. This is for
* example reflected by util_avg's SCHED_CAPACITY_SCALE.
* N.B., the above ratios (runnable% and running%) themselves are in the
* range of [0, 1]. To do fixed point arithmetics, we therefore scale them
* to as large a range as necessary. This is for example reflected by
* util_avg's SCHED_CAPACITY_SCALE.
*
* [Overflow issue]
*
@ -607,7 +599,7 @@ struct task_struct {
randomized_struct_fields_start
void *stack;
atomic_t usage;
refcount_t usage;
/* Per task flags (PF_*), defined further below: */
unsigned int flags;
unsigned int ptrace;
@ -1187,7 +1179,7 @@ struct task_struct {
#endif
#ifdef CONFIG_THREAD_INFO_IN_TASK
/* A live task holds one reference: */
atomic_t stack_refcount;
refcount_t stack_refcount;
#endif
#ifdef CONFIG_LIVEPATCH
int patch_state;
@ -1403,7 +1395,6 @@ extern struct pid *cad_pid;
#define PF_UMH 0x02000000 /* I'm an Usermodehelper process */
#define PF_NO_SETAFFINITY 0x04000000 /* Userland is not allowed to meddle with cpus_allowed */
#define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */
#define PF_MUTEX_TESTER 0x20000000 /* Thread belongs to the rt mutex tester */
#define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */
#define PF_SUSPEND_TASK 0x80000000 /* This thread called freeze_processes() and should not be frozen */
@ -1753,9 +1744,9 @@ static __always_inline bool need_resched(void)
static inline unsigned int task_cpu(const struct task_struct *p)
{
#ifdef CONFIG_THREAD_INFO_IN_TASK
return p->cpu;
return READ_ONCE(p->cpu);
#else
return task_thread_info(p)->cpu;
return READ_ONCE(task_thread_info(p)->cpu);
#endif
}

5
include/linux/sched/signal.h
View File

@ -8,13 +8,14 @@
#include <linux/sched/jobctl.h>
#include <linux/sched/task.h>
#include <linux/cred.h>
#include <linux/refcount.h>
/*
* Types defining task->signal and task->sighand and APIs using them:
*/
struct sighand_struct {
atomic_t count;
refcount_t count;
struct k_sigaction action[_NSIG];
spinlock_t siglock;
wait_queue_head_t signalfd_wqh;
@ -82,7 +83,7 @@ struct multiprocess_signals {
* the locking of signal_struct.
*/
struct signal_struct {
atomic_t sigcnt;
refcount_t sigcnt;
atomic_t live;
int nr_threads;
struct list_head thread_head;

7
include/linux/sched/sysctl.h
View File

@ -83,4 +83,11 @@ extern int sysctl_schedstats(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos);
#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
extern unsigned int sysctl_sched_energy_aware;
extern int sched_energy_aware_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos);
#endif
#endif /* _LINUX_SCHED_SYSCTL_H */

4
include/linux/sched/task.h
View File

@ -88,13 +88,13 @@ extern void sched_exec(void);
#define sched_exec() {}
#endif
#define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0)
#define get_task_struct(tsk) do { refcount_inc(&(tsk)->usage); } while(0)
extern void __put_task_struct(struct task_struct *t);
static inline void put_task_struct(struct task_struct *t)
{
if (atomic_dec_and_test(&t->usage))
if (refcount_dec_and_test(&t->usage))
__put_task_struct(t);
}

2
include/linux/sched/task_stack.h
View File

@ -61,7 +61,7 @@ static inline unsigned long *end_of_stack(struct task_struct *p)
#ifdef CONFIG_THREAD_INFO_IN_TASK
static inline void *try_get_task_stack(struct task_struct *tsk)
{
return atomic_inc_not_zero(&tsk->stack_refcount) ?
return refcount_inc_not_zero(&tsk->stack_refcount) ?
task_stack_page(tsk) : NULL;
}

8
include/linux/sched/topology.h
View File

@ -176,10 +176,10 @@ typedef int (*sched_domain_flags_f)(void);
#define SDTL_OVERLAP 0x01
struct sd_data {
struct sched_domain **__percpu sd;
struct sched_domain_shared **__percpu sds;
struct sched_group **__percpu sg;
struct sched_group_capacity **__percpu sgc;
struct sched_domain *__percpu *sd;
struct sched_domain_shared *__percpu *sds;
struct sched_group *__percpu *sg;
struct sched_group_capacity *__percpu *sgc;
};
struct sched_domain_topology_level {

6
include/linux/wait.h
View File

@ -308,7 +308,7 @@ do { \
#define __wait_event_freezable(wq_head, condition) \
___wait_event(wq_head, condition, TASK_INTERRUPTIBLE, 0, 0, \
schedule(); try_to_freeze())
freezable_schedule())
/**
* wait_event_freezable - sleep (or freeze) until a condition gets true
@ -367,7 +367,7 @@ do { \
#define __wait_event_freezable_timeout(wq_head, condition, timeout) \
___wait_event(wq_head, ___wait_cond_timeout(condition), \
TASK_INTERRUPTIBLE, 0, timeout, \
__ret = schedule_timeout(__ret); try_to_freeze())
__ret = freezable_schedule_timeout(__ret))
/*
* like wait_event_timeout() -- except it uses TASK_INTERRUPTIBLE to avoid
@ -588,7 +588,7 @@ do { \
#define __wait_event_freezable_exclusive(wq, condition) \
___wait_event(wq, condition, TASK_INTERRUPTIBLE, 1, 0, \
schedule(); try_to_freeze())
freezable_schedule())
#define wait_event_freezable_exclusive(wq, condition) \
({ \

6
init/init_task.c
View File

@ -44,7 +44,7 @@ static struct signal_struct init_signals = {
};
static struct sighand_struct init_sighand = {
.count = ATOMIC_INIT(1),
.count = REFCOUNT_INIT(1),
.action = { { { .sa_handler = SIG_DFL, } }, },
.siglock = __SPIN_LOCK_UNLOCKED(init_sighand.siglock),
.signalfd_wqh = __WAIT_QUEUE_HEAD_INITIALIZER(init_sighand.signalfd_wqh),
@ -61,11 +61,11 @@ struct task_struct init_task
= {
#ifdef CONFIG_THREAD_INFO_IN_TASK
.thread_info = INIT_THREAD_INFO(init_task),
.stack_refcount = ATOMIC_INIT(1),
.stack_refcount = REFCOUNT_INIT(1),
#endif
.state = 0,
.stack = init_stack,
.usage = ATOMIC_INIT(2),
.usage = REFCOUNT_INIT(2),
.flags = PF_KTHREAD,
.prio = MAX_PRIO - 20,
.static_prio = MAX_PRIO - 20,

24
kernel/fork.c
View File

@ -429,7 +429,7 @@ static void release_task_stack(struct task_struct *tsk)
#ifdef CONFIG_THREAD_INFO_IN_TASK
void put_task_stack(struct task_struct *tsk)
{
if (atomic_dec_and_test(&tsk->stack_refcount))
if (refcount_dec_and_test(&tsk->stack_refcount))
release_task_stack(tsk);
}
#endif
@ -447,7 +447,7 @@ void free_task(struct task_struct *tsk)
* If the task had a separate stack allocation, it should be gone
* by now.
*/
WARN_ON_ONCE(atomic_read(&tsk->stack_refcount) != 0);
WARN_ON_ONCE(refcount_read(&tsk->stack_refcount) != 0);
#endif
rt_mutex_debug_task_free(tsk);
ftrace_graph_exit_task(tsk);
@ -710,14 +710,14 @@ static inline void free_signal_struct(struct signal_struct *sig)
static inline void put_signal_struct(struct signal_struct *sig)
{
if (atomic_dec_and_test(&sig->sigcnt))
if (refcount_dec_and_test(&sig->sigcnt))
free_signal_struct(sig);
}
void __put_task_struct(struct task_struct *tsk)
{
WARN_ON(!tsk->exit_state);
WARN_ON(atomic_read(&tsk->usage));
WARN_ON(refcount_read(&tsk->usage));
WARN_ON(tsk == current);
cgroup_free(tsk);
@ -867,7 +867,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
tsk->stack_vm_area = stack_vm_area;
#endif
#ifdef CONFIG_THREAD_INFO_IN_TASK
atomic_set(&tsk->stack_refcount, 1);
refcount_set(&tsk->stack_refcount, 1);
#endif
if (err)
@ -896,7 +896,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
* One for us, one for whoever does the "release_task()" (usually
* parent)
*/
atomic_set(&tsk->usage, 2);
refcount_set(&tsk->usage, 2);
#ifdef CONFIG_BLK_DEV_IO_TRACE
tsk->btrace_seq = 0;
#endif
@ -1463,7 +1463,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
struct sighand_struct *sig;
if (clone_flags & CLONE_SIGHAND) {
atomic_inc(&current->sighand->count);
refcount_inc(&current->sighand->count);
return 0;
}
sig = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
@ -1471,7 +1471,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
if (!sig)
return -ENOMEM;
atomic_set(&sig->count, 1);
refcount_set(&sig->count, 1);
spin_lock_irq(&current->sighand->siglock);
memcpy(sig->action, current->sighand->action, sizeof(sig->action));
spin_unlock_irq(&current->sighand->siglock);
@ -1480,7 +1480,7 @@ static int copy_sighand(unsigned long clone_flags, struct task_struct *tsk)
void __cleanup_sighand(struct sighand_struct *sighand)
{
if (atomic_dec_and_test(&sighand->count)) {
if (refcount_dec_and_test(&sighand->count)) {
signalfd_cleanup(sighand);
/*
* sighand_cachep is SLAB_TYPESAFE_BY_RCU so we can free it
@ -1527,7 +1527,7 @@ static int copy_signal(unsigned long clone_flags, struct task_struct *tsk)
sig->nr_threads = 1;
atomic_set(&sig->live, 1);
atomic_set(&sig->sigcnt, 1);
refcount_set(&sig->sigcnt, 1);
/* list_add(thread_node, thread_head) without INIT_LIST_HEAD() */
sig->thread_head = (struct list_head)LIST_HEAD_INIT(tsk->thread_node);
@ -2082,7 +2082,7 @@ static __latent_entropy struct task_struct *copy_process(
} else {
current->signal->nr_threads++;
atomic_inc(&current->signal->live);
atomic_inc(&current->signal->sigcnt);
refcount_inc(&current->signal->sigcnt);
task_join_group_stop(p);
list_add_tail_rcu(&p->thread_group,
&p->group_leader->thread_group);
@ -2439,7 +2439,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
return -EINVAL;
}
if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) {
if (atomic_read(&current->sighand->count) > 1)
if (refcount_read(&current->sighand->count) > 1)
return -EINVAL;
}
if (unshare_flags & CLONE_VM) {

43
kernel/kthread.c
View File

@ -605,7 +605,7 @@ void __kthread_init_worker(struct kthread_worker *worker,
struct lock_class_key *key)
{
memset(worker, 0, sizeof(struct kthread_worker));
spin_lock_init(&worker->lock);
raw_spin_lock_init(&worker->lock);
lockdep_set_class_and_name(&worker->lock, key, name);
INIT_LIST_HEAD(&worker->work_list);
INIT_LIST_HEAD(&worker->delayed_work_list);
@ -647,21 +647,21 @@ repeat:
if (kthread_should_stop()) {
__set_current_state(TASK_RUNNING);
spin_lock_irq(&worker->lock);
raw_spin_lock_irq(&worker->lock);
worker->task = NULL;
spin_unlock_irq(&worker->lock);
raw_spin_unlock_irq(&worker->lock);
return 0;
}
work = NULL;
spin_lock_irq(&worker->lock);
raw_spin_lock_irq(&worker->lock);
if (!list_empty(&worker->work_list)) {
work = list_first_entry(&worker->work_list,
struct kthread_work, node);
list_del_init(&work->node);
}
worker->current_work = work;
spin_unlock_irq(&worker->lock);
raw_spin_unlock_irq(&worker->lock);
if (work) {
__set_current_state(TASK_RUNNING);
@ -818,12 +818,12 @@ bool kthread_queue_work(struct kthread_worker *worker,
bool ret = false;
unsigned long flags;
spin_lock_irqsave(&worker->lock, flags);
raw_spin_lock_irqsave(&worker->lock, flags);
if (!queuing_blocked(worker, work)) {
kthread_insert_work(worker, work, &worker->work_list);
ret = true;
}
spin_unlock_irqrestore(&worker->lock, flags);
raw_spin_unlock_irqrestore(&worker->lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(kthread_queue_work);
@ -841,6 +841,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t)
struct kthread_delayed_work *dwork = from_timer(dwork, t, timer);
struct kthread_work *work = &dwork->work;
struct kthread_worker *worker = work->worker;
unsigned long flags;
/*
* This might happen when a pending work is reinitialized.
@ -849,7 +850,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t)
if (WARN_ON_ONCE(!worker))
return;
spin_lock(&worker->lock);
raw_spin_lock_irqsave(&worker->lock, flags);
/* Work must not be used with >1 worker, see kthread_queue_work(). */
WARN_ON_ONCE(work->worker != worker);
@ -858,7 +859,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t)
list_del_init(&work->node);
kthread_insert_work(worker, work, &worker->work_list);
spin_unlock(&worker->lock);
raw_spin_unlock_irqrestore(&worker->lock, flags);
}
EXPORT_SYMBOL(kthread_delayed_work_timer_fn);
@ -914,14 +915,14 @@ bool kthread_queue_delayed_work(struct kthread_worker *worker,
unsigned long flags;
bool ret = false;
spin_lock_irqsave(&worker->lock, flags);
raw_spin_lock_irqsave(&worker->lock, flags);
if (!queuing_blocked(worker, work)) {
__kthread_queue_delayed_work(worker, dwork, delay);
ret = true;
}
spin_unlock_irqrestore(&worker->lock, flags);
raw_spin_unlock_irqrestore(&worker->lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(kthread_queue_delayed_work);
@ -957,7 +958,7 @@ void kthread_flush_work(struct kthread_work *work)
if (!worker)
return;
spin_lock_irq(&worker->lock);
raw_spin_lock_irq(&worker->lock);
/* Work must not be used with >1 worker, see kthread_queue_work(). */
WARN_ON_ONCE(work->worker != worker);
@ -969,7 +970,7 @@ void kthread_flush_work(struct kthread_work *work)
else
noop = true;
spin_unlock_irq(&worker->lock);
raw_spin_unlock_irq(&worker->lock);
if (!noop)
wait_for_completion(&fwork.done);
@ -1002,9 +1003,9 @@ static bool __kthread_cancel_work(struct kthread_work *work, bool is_dwork,
* any queuing is blocked by setting the canceling counter.
*/
work->canceling++;
spin_unlock_irqrestore(&worker->lock, *flags);
raw_spin_unlock_irqrestore(&worker->lock, *flags);
del_timer_sync(&dwork->timer);
spin_lock_irqsave(&worker->lock, *flags);
raw_spin_lock_irqsave(&worker->lock, *flags);
work->canceling--;
}
@ -1051,7 +1052,7 @@ bool kthread_mod_delayed_work(struct kthread_worker *worker,
unsigned long flags;
int ret = false;
spin_lock_irqsave(&worker->lock, flags);
raw_spin_lock_irqsave(&worker->lock, flags);
/* Do not bother with canceling when never queued. */
if (!work->worker)
@ -1068,7 +1069,7 @@ bool kthread_mod_delayed_work(struct kthread_worker *worker,
fast_queue:
__kthread_queue_delayed_work(worker, dwork, delay);
out:
spin_unlock_irqrestore(&worker->lock, flags);
raw_spin_unlock_irqrestore(&worker->lock, flags);
return ret;
}
EXPORT_SYMBOL_GPL(kthread_mod_delayed_work);
@ -1082,7 +1083,7 @@ static bool __kthread_cancel_work_sync(struct kthread_work *work, bool is_dwork)
if (!worker)
goto out;
spin_lock_irqsave(&worker->lock, flags);
raw_spin_lock_irqsave(&worker->lock, flags);
/* Work must not be used with >1 worker, see kthread_queue_work(). */
WARN_ON_ONCE(work->worker != worker);
@ -1096,13 +1097,13 @@ static bool __kthread_cancel_work_sync(struct kthread_work *work, bool is_dwork)
* In the meantime, block any queuing by setting the canceling counter.
*/
work->canceling++;
spin_unlock_irqrestore(&worker->lock, flags);
raw_spin_unlock_irqrestore(&worker->lock, flags);
kthread_flush_work(work);
spin_lock_irqsave(&worker->lock, flags);
raw_spin_lock_irqsave(&worker->lock, flags);
work->canceling--;
out_fast:
spin_unlock_irqrestore(&worker->lock, flags);
raw_spin_unlock_irqrestore(&worker->lock, flags);
out:
return ret;
}

12
kernel/sched/core.c
View File

@ -107,11 +107,12 @@ struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
* [L] ->on_rq
* RELEASE (rq->lock)
*
* If we observe the old CPU in task_rq_lock, the acquire of
* If we observe the old CPU in task_rq_lock(), the acquire of
* the old rq->lock will fully serialize against the stores.
*
* If we observe the new CPU in task_rq_lock, the acquire will
* pair with the WMB to ensure we must then also see migrating.
* If we observe the new CPU in task_rq_lock(), the address
* dependency headed by '[L] rq = task_rq()' and the acquire
* will pair with the WMB to ensure we then also see migrating.
*/
if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
rq_pin_lock(rq, rf);
@ -180,6 +181,7 @@ static void update_rq_clock_task(struct rq *rq, s64 delta)
if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY))
update_irq_load_avg(rq, irq_delta + steal);
#endif
update_rq_clock_pelt(rq, delta);
}
void update_rq_clock(struct rq *rq)
@ -956,7 +958,7 @@ static struct rq *move_queued_task(struct rq *rq, struct rq_flags *rf,
{
lockdep_assert_held(&rq->lock);
p->on_rq = TASK_ON_RQ_MIGRATING;
WRITE_ONCE(p->on_rq, TASK_ON_RQ_MIGRATING);
dequeue_task(rq, p, DEQUEUE_NOCLOCK);
set_task_cpu(p, new_cpu);
rq_unlock(rq, rf);
@ -2459,7 +2461,7 @@ void wake_up_new_task(struct task_struct *p)
#endif
rq = __task_rq_lock(p, &rf);
update_rq_clock(rq);
post_init_entity_util_avg(&p->se);
post_init_entity_util_avg(p);
activate_task(rq, p, ENQUEUE_NOCLOCK);
p->on_rq = TASK_ON_RQ_QUEUED;

6
kernel/sched/deadline.c
View File

@ -1767,7 +1767,7 @@ pick_next_task_dl(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
deadline_queue_push_tasks(rq);
if (rq->curr->sched_class != &dl_sched_class)
update_dl_rq_load_avg(rq_clock_task(rq), rq, 0);
update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 0);
return p;
}
@ -1776,7 +1776,7 @@ static void put_prev_task_dl(struct rq *rq, struct task_struct *p)
{
update_curr_dl(rq);
update_dl_rq_load_avg(rq_clock_task(rq), rq, 1);
update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1);
if (on_dl_rq(&p->dl) && p->nr_cpus_allowed > 1)
enqueue_pushable_dl_task(rq, p);
}
@ -1793,7 +1793,7 @@ static void task_tick_dl(struct rq *rq, struct task_struct *p, int queued)
{
update_curr_dl(rq);
update_dl_rq_load_avg(rq_clock_task(rq), rq, 1);
update_dl_rq_load_avg(rq_clock_pelt(rq), rq, 1);
/*
* Even when we have runtime, update_curr_dl() might have resulted in us
* not being the leftmost task anymore. In that case NEED_RESCHED will

4
kernel/sched/debug.c
View File

@ -315,6 +315,7 @@ void register_sched_domain_sysctl(void)
{
static struct ctl_table *cpu_entries;
static struct ctl_table **cpu_idx;
static bool init_done = false;
char buf[32];
int i;
@ -344,7 +345,10 @@ void register_sched_domain_sysctl(void)
if (!cpumask_available(sd_sysctl_cpus)) {
if (!alloc_cpumask_var(&sd_sysctl_cpus, GFP_KERNEL))
return;
}
if (!init_done) {
init_done = true;
/* init to possible to not have holes in @cpu_entries */
cpumask_copy(sd_sysctl_cpus, cpu_possible_mask);
}

462
kernel/sched/fair.c
View File

@ -248,13 +248,6 @@ const struct sched_class fair_sched_class;
*/
#ifdef CONFIG_FAIR_GROUP_SCHED
/* cpu runqueue to which this cfs_rq is attached */
static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
{
return cfs_rq->rq;
}
static inline struct task_struct *task_of(struct sched_entity *se)
{
SCHED_WARN_ON(!entity_is_task(se));
@ -282,79 +275,103 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
return grp->my_q;
}
static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
{
if (!cfs_rq->on_list) {
struct rq *rq = rq_of(cfs_rq);
int cpu = cpu_of(rq);
/*
* Ensure we either appear before our parent (if already
* enqueued) or force our parent to appear after us when it is
* enqueued. The fact that we always enqueue bottom-up
* reduces this to two cases and a special case for the root
* cfs_rq. Furthermore, it also means that we will always reset
* tmp_alone_branch either when the branch is connected
* to a tree or when we reach the beg of the tree
*/
if (cfs_rq->tg->parent &&
cfs_rq->tg->parent->cfs_rq[cpu]->on_list) {
/*
* If parent is already on the list, we add the child
* just before. Thanks to circular linked property of
* the list, this means to put the child at the tail
* of the list that starts by parent.
*/
list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
&(cfs_rq->tg->parent->cfs_rq[cpu]->leaf_cfs_rq_list));
/*
* The branch is now connected to its tree so we can
* reset tmp_alone_branch to the beginning of the
* list.
*/
rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
} else if (!cfs_rq->tg->parent) {
/*
* cfs rq without parent should be put
* at the tail of the list.
*/
list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
&rq->leaf_cfs_rq_list);
/*
* We have reach the beg of a tree so we can reset
* tmp_alone_branch to the beginning of the list.
*/
rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
} else {
/*
* The parent has not already been added so we want to
* make sure that it will be put after us.
* tmp_alone_branch points to the beg of the branch
* where we will add parent.
*/
list_add_rcu(&cfs_rq->leaf_cfs_rq_list,
rq->tmp_alone_branch);
/*
* update tmp_alone_branch to points to the new beg
* of the branch
*/
rq->tmp_alone_branch = &cfs_rq->leaf_cfs_rq_list;
}
struct rq *rq = rq_of(cfs_rq);
int cpu = cpu_of(rq);
cfs_rq->on_list = 1;
if (cfs_rq->on_list)
return rq->tmp_alone_branch == &rq->leaf_cfs_rq_list;
cfs_rq->on_list = 1;
/*
* Ensure we either appear before our parent (if already
* enqueued) or force our parent to appear after us when it is
* enqueued. The fact that we always enqueue bottom-up
* reduces this to two cases and a special case for the root
* cfs_rq. Furthermore, it also means that we will always reset
* tmp_alone_branch either when the branch is connected
* to a tree or when we reach the top of the tree
*/
if (cfs_rq->tg->parent &&
cfs_rq->tg->parent->cfs_rq[cpu]->on_list) {
/*
* If parent is already on the list, we add the child
* just before. Thanks to circular linked property of
* the list, this means to put the child at the tail
* of the list that starts by parent.
*/
list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
&(cfs_rq->tg->parent->cfs_rq[cpu]->leaf_cfs_rq_list));
/*
* The branch is now connected to its tree so we can
* reset tmp_alone_branch to the beginning of the
* list.
*/
rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
return true;
}
if (!cfs_rq->tg->parent) {
/*
* cfs rq without parent should be put
* at the tail of the list.
*/
list_add_tail_rcu(&cfs_rq->leaf_cfs_rq_list,
&rq->leaf_cfs_rq_list);
/*
* We have reach the top of a tree so we can reset
* tmp_alone_branch to the beginning of the list.
*/
rq->tmp_alone_branch = &rq->leaf_cfs_rq_list;
return true;
}
/*
* The parent has not already been added so we want to
* make sure that it will be put after us.
* tmp_alone_branch points to the begin of the branch
* where we will add parent.
*/
list_add_rcu(&cfs_rq->leaf_cfs_rq_list, rq->tmp_alone_branch);
/*
* update tmp_alone_branch to points to the new begin
* of the branch
*/
rq->tmp_alone_branch = &cfs_rq->leaf_cfs_rq_list;
return false;
}
static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
{
if (cfs_rq->on_list) {
struct rq *rq = rq_of(cfs_rq);
/*
* With cfs_rq being unthrottled/throttled during an enqueue,
* it can happen the tmp_alone_branch points the a leaf that
* we finally want to del. In this case, tmp_alone_branch moves
* to the prev element but it will point to rq->leaf_cfs_rq_list
* at the end of the enqueue.
*/
if (rq->tmp_alone_branch == &cfs_rq->leaf_cfs_rq_list)
rq->tmp_alone_branch = cfs_rq->leaf_cfs_rq_list.prev;
list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
cfs_rq->on_list = 0;
}
}
/* Iterate through all leaf cfs_rq's on a runqueue: */
#define for_each_leaf_cfs_rq(rq, cfs_rq) \
list_for_each_entry_rcu(cfs_rq, &rq->leaf_cfs_rq_list, leaf_cfs_rq_list)
static inline void assert_list_leaf_cfs_rq(struct rq *rq)
{
SCHED_WARN_ON(rq->tmp_alone_branch != &rq->leaf_cfs_rq_list);
}
/* Iterate thr' all leaf cfs_rq's on a runqueue */
#define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) \
list_for_each_entry_safe(cfs_rq, pos, &rq->leaf_cfs_rq_list, \
leaf_cfs_rq_list)
/* Do the two (enqueued) entities belong to the same group ? */
static inline struct cfs_rq *
@ -410,12 +427,6 @@ static inline struct task_struct *task_of(struct sched_entity *se)
return container_of(se, struct task_struct, se);
}
static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
{
return container_of(cfs_rq, struct rq, cfs);
}
#define for_each_sched_entity(se) \
for (; se; se = NULL)
@ -438,16 +449,21 @@ static inline struct cfs_rq *group_cfs_rq(struct sched_entity *grp)
return NULL;
}
static inline void list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
static inline bool list_add_leaf_cfs_rq(struct cfs_rq *cfs_rq)
{
return true;
}
static inline void list_del_leaf_cfs_rq(struct cfs_rq *cfs_rq)
{
}
#define for_each_leaf_cfs_rq(rq, cfs_rq) \
for (cfs_rq = &rq->cfs; cfs_rq; cfs_rq = NULL)
static inline void assert_list_leaf_cfs_rq(struct rq *rq)
{
}
#define for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) \
for (cfs_rq = &rq->cfs, pos = NULL; cfs_rq; cfs_rq = pos)
static inline struct sched_entity *parent_entity(struct sched_entity *se)
{
@ -686,9 +702,8 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
return calc_delta_fair(sched_slice(cfs_rq, se), se);
}
#ifdef CONFIG_SMP
#include "pelt.h"
#include "sched-pelt.h"
#ifdef CONFIG_SMP
static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu);
static unsigned long task_h_load(struct task_struct *p);
@ -744,8 +759,9 @@ static void attach_entity_cfs_rq(struct sched_entity *se);
* Finally, that extrapolated util_avg is clamped to the cap (util_avg_cap)
* if util_avg > util_avg_cap.
*/
void post_init_entity_util_avg(struct sched_entity *se)
void post_init_entity_util_avg(struct task_struct *p)
{
struct sched_entity *se = &p->se;
struct cfs_rq *cfs_rq = cfs_rq_of(se);
struct sched_avg *sa = &se->avg;
long cpu_scale = arch_scale_cpu_capacity(NULL, cpu_of(rq_of(cfs_rq)));
@ -763,22 +779,19 @@ void post_init_entity_util_avg(struct sched_entity *se)
}
}
if (entity_is_task(se)) {
struct task_struct *p = task_of(se);
if (p->sched_class != &fair_sched_class) {
/*
* For !fair tasks do:
*
update_cfs_rq_load_avg(now, cfs_rq);
attach_entity_load_avg(cfs_rq, se, 0);
switched_from_fair(rq, p);
*
* such that the next switched_to_fair() has the
* expected state.
*/
se->avg.last_update_time = cfs_rq_clock_task(cfs_rq);
return;
}
if (p->sched_class != &fair_sched_class) {
/*
* For !fair tasks do:
*
update_cfs_rq_load_avg(now, cfs_rq);
attach_entity_load_avg(cfs_rq, se, 0);
switched_from_fair(rq, p);
*
* such that the next switched_to_fair() has the
* expected state.
*/
se->avg.last_update_time = cfs_rq_clock_pelt(cfs_rq);
return;
}
attach_entity_cfs_rq(se);
@ -788,7 +801,7 @@ void post_init_entity_util_avg(struct sched_entity *se)
void init_entity_runnable_average(struct sched_entity *se)
{
}
void post_init_entity_util_avg(struct sched_entity *se)
void post_init_entity_util_avg(struct task_struct *p)
{
}
static void update_tg_load_avg(struct cfs_rq *cfs_rq, int force)
@ -1035,7 +1048,7 @@ unsigned int sysctl_numa_balancing_scan_size = 256;
unsigned int sysctl_numa_balancing_scan_delay = 1000;
struct numa_group {
atomic_t refcount;
refcount_t refcount;
spinlock_t lock; /* nr_tasks, tasks */
int nr_tasks;
@ -1104,7 +1117,7 @@ static unsigned int task_scan_start(struct task_struct *p)
unsigned long shared = group_faults_shared(ng);
unsigned long private = group_faults_priv(ng);
period *= atomic_read(&ng->refcount);
period *= refcount_read(&ng->refcount);
period *= shared + 1;
period /= private + shared + 1;
}
@ -1127,7 +1140,7 @@ static unsigned int task_scan_max(struct task_struct *p)
unsigned long private = group_faults_priv(ng);
unsigned long period = smax;
period *= atomic_read(&ng->refcount);
period *= refcount_read(&ng->refcount);
period *= shared + 1;
period /= private + shared + 1;
@ -2203,12 +2216,12 @@ static void task_numa_placement(struct task_struct *p)
static inline int get_numa_group(struct numa_group *grp)
{
return atomic_inc_not_zero(&grp->refcount);
return refcount_inc_not_zero(&grp->refcount);
}
static inline void put_numa_group(struct numa_group *grp)
{
if (atomic_dec_and_test(&grp->refcount))
if (refcount_dec_and_test(&grp->refcount))
kfree_rcu(grp, rcu);
}
@ -2229,7 +2242,7 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
if (!grp)
return;
atomic_set(&grp->refcount, 1);
refcount_set(&grp->refcount, 1);
grp->active_nodes = 1;
grp->max_faults_cpu = 0;
spin_lock_init(&grp->lock);
@ -3122,7 +3135,7 @@ void set_task_rq_fair(struct sched_entity *se,
p_last_update_time = prev->avg.last_update_time;
n_last_update_time = next->avg.last_update_time;
#endif
__update_load_avg_blocked_se(p_last_update_time, cpu_of(rq_of(prev)), se);
__update_load_avg_blocked_se(p_last_update_time, se);
se->avg.last_update_time = n_last_update_time;
}
@ -3257,11 +3270,11 @@ update_tg_cfs_runnable(struct cfs_rq *cfs_rq, struct sched_entity *se, struct cf
/*
* runnable_sum can't be lower than running_sum
* As running sum is scale with CPU capacity wehreas the runnable sum
* is not we rescale running_sum 1st
* Rescale running sum to be in the same range as runnable sum
* running_sum is in [0 : LOAD_AVG_MAX << SCHED_CAPACITY_SHIFT]
* runnable_sum is in [0 : LOAD_AVG_MAX]
*/
running_sum = se->avg.util_sum /
arch_scale_cpu_capacity(NULL, cpu_of(rq_of(cfs_rq)));
running_sum = se->avg.util_sum >> SCHED_CAPACITY_SHIFT;
runnable_sum = max(runnable_sum, running_sum);
load_sum = (s64)se_weight(se) * runnable_sum;
@ -3364,7 +3377,7 @@ static inline void add_tg_cfs_propagate(struct cfs_rq *cfs_rq, long runnable_sum
/**
* update_cfs_rq_load_avg - update the cfs_rq's load/util averages
* @now: current time, as per cfs_rq_clock_task()
* @now: current time, as per cfs_rq_clock_pelt()
* @cfs_rq: cfs_rq to update
*
* The cfs_rq avg is the direct sum of all its entities (blocked and runnable)
@ -3409,7 +3422,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
decayed = 1;
}
decayed |= __update_load_avg_cfs_rq(now, cpu_of(rq_of(cfs_rq)), cfs_rq);
decayed |= __update_load_avg_cfs_rq(now, cfs_rq);
#ifndef CONFIG_64BIT
smp_wmb();
@ -3499,9 +3512,7 @@ static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
/* Update task and its cfs_rq load average */
static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
{
u64 now = cfs_rq_clock_task(cfs_rq);
struct rq *rq = rq_of(cfs_rq);
int cpu = cpu_of(rq);
u64 now = cfs_rq_clock_pelt(cfs_rq);
int decayed;
/*
@ -3509,7 +3520,7 @@ static inline void update_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *s
* track group sched_entity load average for task_h_load calc in migration
*/
if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD))
__update_load_avg_se(now, cpu, cfs_rq, se);
__update_load_avg_se(now, cfs_rq, se);
decayed = update_cfs_rq_load_avg(now, cfs_rq);
decayed |= propagate_entity_load_avg(se);
@ -3561,7 +3572,7 @@ void sync_entity_load_avg(struct sched_entity *se)
u64 last_update_time;
last_update_time = cfs_rq_last_update_time(cfs_rq);
__update_load_avg_blocked_se(last_update_time, cpu_of(rq_of(cfs_rq)), se);
__update_load_avg_blocked_se(last_update_time, se);
}
/*
@ -3577,10 +3588,6 @@ void remove_entity_load_avg(struct sched_entity *se)
* tasks cannot exit without having gone through wake_up_new_task() ->
* post_init_entity_util_avg() which will have added things to the
* cfs_rq, so we can remove unconditionally.
*
* Similarly for groups, they will have passed through
* post_init_entity_util_avg() before unregister_sched_fair_group()
* calls this.
*/
sync_entity_load_avg(se);
@ -3654,6 +3661,7 @@ util_est_dequeue(struct cfs_rq *cfs_rq, struct task_struct *p, bool task_sleep)
{
long last_ewma_diff;
struct util_est ue;
int cpu;
if (!sched_feat(UTIL_EST))
return;
@ -3687,6 +3695,14 @@ util_est_dequeue(struct cfs_rq *cfs_rq, struct task_struct *p, bool task_sleep)
if (within_margin(last_ewma_diff, (SCHED_CAPACITY_SCALE / 100)))
return;
/*
* To avoid overestimation of actual task utilization, skip updates if
* we cannot grant there is idle time in this CPU.
*/
cpu = cpu_of(rq_of(cfs_rq));
if (task_util(p) > capacity_orig_of(cpu))
return;
/*
* Update Task's estimated utilization
*
@ -4429,6 +4445,10 @@ static int tg_unthrottle_up(struct task_group *tg, void *data)
/* adjust cfs_rq_clock_task() */
cfs_rq->throttled_clock_task_time += rq_clock_task(rq) -
cfs_rq->throttled_clock_task;
/* Add cfs_rq with already running entity in the list */
if (cfs_rq->nr_running >= 1)
list_add_leaf_cfs_rq(cfs_rq);
}
return 0;
@ -4440,8 +4460,10 @@ static int tg_throttle_down(struct task_group *tg, void *data)
struct cfs_rq *cfs_rq = tg->cfs_rq[cpu_of(rq)];
/* group is entering throttled state, stop time */
if (!cfs_rq->throttle_count)
if (!cfs_rq->throttle_count) {
cfs_rq->throttled_clock_task = rq_clock_task(rq);
list_del_leaf_cfs_rq(cfs_rq);
}
cfs_rq->throttle_count++;
return 0;
@ -4544,6 +4566,8 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
break;
}
assert_list_leaf_cfs_rq(rq);
if (!se)
add_nr_running(rq, task_delta);
@ -4565,7 +4589,7 @@ static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b,
struct rq *rq = rq_of(cfs_rq);
struct rq_flags rf;
rq_lock(rq, &rf);
rq_lock_irqsave(rq, &rf);
if (!cfs_rq_throttled(cfs_rq))
goto next;
@ -4582,7 +4606,7 @@ static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b,
unthrottle_cfs_rq(cfs_rq);
next:
rq_unlock(rq, &rf);
rq_unlock_irqrestore(rq, &rf);
if (!remaining)
break;
@ -4598,7 +4622,7 @@ next:
* period the timer is deactivated until scheduling resumes; cfs_b->idle is
* used to track this state.
*/
static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun, unsigned long flags)
{
u64 runtime, runtime_expires;
int throttled;
@ -4640,11 +4664,11 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
while (throttled && cfs_b->runtime > 0 && !cfs_b->distribute_running) {
runtime = cfs_b->runtime;
cfs_b->distribute_running = 1;
raw_spin_unlock(&cfs_b->lock);
raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
/* we can't nest cfs_b->lock while distributing bandwidth */
runtime = distribute_cfs_runtime(cfs_b, runtime,
runtime_expires);
raw_spin_lock(&cfs_b->lock);
raw_spin_lock_irqsave(&cfs_b->lock, flags);
cfs_b->distribute_running = 0;
throttled = !list_empty(&cfs_b->throttled_cfs_rq);
@ -4753,17 +4777,18 @@ static __always_inline void return_cfs_rq_runtime(struct cfs_rq *cfs_rq)
static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
{
u64 runtime = 0, slice = sched_cfs_bandwidth_slice();
unsigned long flags;
u64 expires;
/* confirm we're still not at a refresh boundary */
raw_spin_lock(&cfs_b->lock);
raw_spin_lock_irqsave(&cfs_b->lock, flags);
if (cfs_b->distribute_running) {
raw_spin_unlock(&cfs_b->lock);
raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
return;
}
if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) {
raw_spin_unlock(&cfs_b->lock);
raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
return;
}
@ -4774,18 +4799,18 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
if (runtime)
cfs_b->distribute_running = 1;
raw_spin_unlock(&cfs_b->lock);
raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
if (!runtime)
return;
runtime = distribute_cfs_runtime(cfs_b, runtime, expires);
raw_spin_lock(&cfs_b->lock);
raw_spin_lock_irqsave(&cfs_b->lock, flags);
if (expires == cfs_b->runtime_expires)
lsub_positive(&cfs_b->runtime, runtime);
cfs_b->distribute_running = 0;
raw_spin_unlock(&cfs_b->lock);
raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
}
/*
@ -4863,20 +4888,21 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
{
struct cfs_bandwidth *cfs_b =
container_of(timer, struct cfs_bandwidth, period_timer);
unsigned long flags;
int overrun;
int idle = 0;
raw_spin_lock(&cfs_b->lock);
raw_spin_lock_irqsave(&cfs_b->lock, flags);
for (;;) {
overrun = hrtimer_forward_now(timer, cfs_b->period);
if (!overrun)
break;
idle = do_sched_cfs_period_timer(cfs_b, overrun);
idle = do_sched_cfs_period_timer(cfs_b, overrun, flags);
}
if (idle)
cfs_b->period_active = 0;
raw_spin_unlock(&cfs_b->lock);
raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
}
@ -4986,6 +5012,12 @@ static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq)
}
#else /* CONFIG_CFS_BANDWIDTH */
static inline bool cfs_bandwidth_used(void)
{
return false;
}
static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq)
{
return rq_clock_task(rq_of(cfs_rq));
@ -5177,6 +5209,23 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
}
if (cfs_bandwidth_used()) {
/*
* When bandwidth control is enabled; the cfs_rq_throttled()
* breaks in the above iteration can result in incomplete
* leaf list maintenance, resulting in triggering the assertion
* below.
*/
for_each_sched_entity(se) {
cfs_rq = cfs_rq_of(se);
if (list_add_leaf_cfs_rq(cfs_rq))
break;
}
}
assert_list_leaf_cfs_rq(rq);
hrtick_update(rq);
}
@ -5556,11 +5605,6 @@ static unsigned long capacity_of(int cpu)
return cpu_rq(cpu)->cpu_capacity;
}
static unsigned long capacity_orig_of(int cpu)
{
return cpu_rq(cpu)->cpu_capacity_orig;
}
static unsigned long cpu_avg_load_per_task(int cpu)
{
struct rq *rq = cpu_rq(cpu);
@ -6053,7 +6097,7 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int
bool idle = true;
for_each_cpu(cpu, cpu_smt_mask(core)) {
cpumask_clear_cpu(cpu, cpus);
__cpumask_clear_cpu(cpu, cpus);
if (!available_idle_cpu(cpu))
idle = false;
}
@ -6073,7 +6117,7 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int
/*
* Scan the local SMT mask for idle CPUs.
*/
static int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int target)
static int select_idle_smt(struct task_struct *p, int target)
{
int cpu;
@ -6097,7 +6141,7 @@ static inline int select_idle_core(struct task_struct *p, struct sched_domain *s
return -1;
}
static inline int select_idle_smt(struct task_struct *p, struct sched_domain *sd, int target)
static inline int select_idle_smt(struct task_struct *p, int target)
{
return -1;
}
@ -6202,7 +6246,7 @@ static int select_idle_sibling(struct task_struct *p, int prev, int target)
if ((unsigned)i < nr_cpumask_bits)
return i;
i = select_idle_smt(p, sd, target);
i = select_idle_smt(p, target);
if ((unsigned)i < nr_cpumask_bits)
return i;
@ -6608,7 +6652,7 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
if (sd_flag & SD_BALANCE_WAKE) {
record_wakee(p);
if (static_branch_unlikely(&sched_energy_present)) {
if (sched_energy_enabled()) {
new_cpu = find_energy_efficient_cpu(p, prev_cpu);
if (new_cpu >= 0)
return new_cpu;
@ -7027,6 +7071,12 @@ idle:
if (new_tasks > 0)
goto again;
/*
* rq is about to be idle, check if we need to update the
* lost_idle_time of clock_pelt
*/
update_idle_rq_clock_pelt(rq);
return NULL;
}
@ -7647,10 +7697,27 @@ static inline bool others_have_blocked(struct rq *rq)
#ifdef CONFIG_FAIR_GROUP_SCHED
static inline bool cfs_rq_is_decayed(struct cfs_rq *cfs_rq)
{
if (cfs_rq->load.weight)
return false;
if (cfs_rq->avg.load_sum)
return false;
if (cfs_rq->avg.util_sum)
return false;
if (cfs_rq->avg.runnable_load_sum)
return false;
return true;
}
static void update_blocked_averages(int cpu)
{
struct rq *rq = cpu_rq(cpu);
struct cfs_rq *cfs_rq;
struct cfs_rq *cfs_rq, *pos;
const struct sched_class *curr_class;
struct rq_flags rf;
bool done = true;
@ -7662,14 +7729,10 @@ static void update_blocked_averages(int cpu)
* Iterates the task_group tree in a bottom up fashion, see
* list_add_leaf_cfs_rq() for details.
*/
for_each_leaf_cfs_rq(rq, cfs_rq) {
for_each_leaf_cfs_rq_safe(rq, cfs_rq, pos) {
struct sched_entity *se;
/* throttled entities do not contribute to load */
if (throttled_hierarchy(cfs_rq))
continue;
if (update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq))
if (update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq))
update_tg_load_avg(cfs_rq, 0);
/* Propagate pending load changes to the parent, if any: */
@ -7677,14 +7740,21 @@ static void update_blocked_averages(int cpu)
if (se && !skip_blocked_update(se))
update_load_avg(cfs_rq_of(se), se, 0);
/*
* There can be a lot of idle CPU cgroups. Don't let fully
* decayed cfs_rqs linger on the list.
*/
if (cfs_rq_is_decayed(cfs_rq))
list_del_leaf_cfs_rq(cfs_rq);
/* Don't need periodic decay once load/util_avg are null */
if (cfs_rq_has_blocked(cfs_rq))
done = false;
}
curr_class = rq->curr->sched_class;
update_rt_rq_load_avg(rq_clock_task(rq), rq, curr_class == &rt_sched_class);
update_dl_rq_load_avg(rq_clock_task(rq), rq, curr_class == &dl_sched_class);
update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);
update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);
update_irq_load_avg(rq, 0);
/* Don't need periodic decay once load/util_avg are null */
if (others_have_blocked(rq))
@ -7754,11 +7824,11 @@ static inline void update_blocked_averages(int cpu)
rq_lock_irqsave(rq, &rf);
update_rq_clock(rq);
update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq);
update_cfs_rq_load_avg(cfs_rq_clock_pelt(cfs_rq), cfs_rq);
curr_class = rq->curr->sched_class;
update_rt_rq_load_avg(rq_clock_task(rq), rq, curr_class == &rt_sched_class);
update_dl_rq_load_avg(rq_clock_task(rq), rq, curr_class == &dl_sched_class);
update_rt_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &rt_sched_class);
update_dl_rq_load_avg(rq_clock_pelt(rq), rq, curr_class == &dl_sched_class);
update_irq_load_avg(rq, 0);
#ifdef CONFIG_NO_HZ_COMMON
rq->last_blocked_load_update_tick = jiffies;
@ -8452,9 +8522,7 @@ static int check_asym_packing(struct lb_env *env, struct sd_lb_stats *sds)
if (sched_asym_prefer(busiest_cpu, env->dst_cpu))
return 0;
env->imbalance = DIV_ROUND_CLOSEST(
sds->busiest_stat.avg_load * sds->busiest_stat.group_capacity,
SCHED_CAPACITY_SCALE);
env->imbalance = sds->busiest_stat.group_load;
return 1;
}
@ -8636,7 +8704,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
*/
update_sd_lb_stats(env, &sds);
if (static_branch_unlikely(&sched_energy_present)) {
if (sched_energy_enabled()) {
struct root_domain *rd = env->dst_rq->rd;
if (rcu_dereference(rd->pd) && !READ_ONCE(rd->overutilized))
@ -8827,21 +8895,25 @@ static struct rq *find_busiest_queue(struct lb_env *env,
*/
#define MAX_PINNED_INTERVAL 512
static int need_active_balance(struct lb_env *env)
static inline bool
asym_active_balance(struct lb_env *env)
{
/*
* ASYM_PACKING needs to force migrate tasks from busy but
* lower priority CPUs in order to pack all tasks in the
* highest priority CPUs.
*/
return env->idle != CPU_NOT_IDLE && (env->sd->flags & SD_ASYM_PACKING) &&
sched_asym_prefer(env->dst_cpu, env->src_cpu);
}
static inline bool
voluntary_active_balance(struct lb_env *env)
{
struct sched_domain *sd = env->sd;
if (env->idle == CPU_NEWLY_IDLE) {
/*
* ASYM_PACKING needs to force migrate tasks from busy but
* lower priority CPUs in order to pack all tasks in the
* highest priority CPUs.
*/
if ((sd->flags & SD_ASYM_PACKING) &&
sched_asym_prefer(env->dst_cpu, env->src_cpu))
return 1;
}
if (asym_active_balance(env))
return 1;
/*
* The dst_cpu is idle and the src_cpu CPU has only 1 CFS task.
@ -8859,6 +8931,16 @@ static int need_active_balance(struct lb_env *env)
if (env->src_grp_type == group_misfit_task)
return 1;
return 0;
}
static int need_active_balance(struct lb_env *env)
{
struct sched_domain *sd = env->sd;
if (voluntary_active_balance(env))
return 1;
return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2);
}
@ -9023,7 +9105,7 @@ more_balance:
if ((env.flags & LBF_DST_PINNED) && env.imbalance > 0) {
/* Prevent to re-select dst_cpu via env's CPUs */
cpumask_clear_cpu(env.dst_cpu, env.cpus);
__cpumask_clear_cpu(env.dst_cpu, env.cpus);
env.dst_rq = cpu_rq(env.new_dst_cpu);
env.dst_cpu = env.new_dst_cpu;
@ -9050,7 +9132,7 @@ more_balance:
/* All tasks on this runqueue were pinned by CPU affinity */
if (unlikely(env.flags & LBF_ALL_PINNED)) {
cpumask_clear_cpu(cpu_of(busiest), cpus);
__cpumask_clear_cpu(cpu_of(busiest), cpus);
/*
* Attempting to continue load balancing at the current
* sched_domain level only makes sense if there are
@ -9120,7 +9202,7 @@ more_balance:
} else
sd->nr_balance_failed = 0;
if (likely(!active_balance)) {
if (likely(!active_balance) || voluntary_active_balance(&env)) {
/* We were unbalanced, so reset the balancing interval */
sd->balance_interval = sd->min_interval;
} else {
@ -9469,15 +9551,8 @@ static void kick_ilb(unsigned int flags)
}
/*
* Current heuristic for kicking the idle load balancer in the presence
* of an idle cpu in the system.
* - This rq has more than one task.
* - This rq has at least one CFS task and the capacity of the CPU is
* significantly reduced because of RT tasks or IRQs.
* - At parent of LLC scheduler domain level, this cpu's scheduler group has
* multiple busy cpu.
* - For SD_ASYM_PACKING, if the lower numbered cpu's in the scheduler
* domain span are idle.
* Current decision point for kicking the idle load balancer in the presence
* of idle CPUs in the system.
*/
static void nohz_balancer_kick(struct rq *rq)
{
@ -9519,8 +9594,13 @@ static void nohz_balancer_kick(struct rq *rq)
sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
if (sds) {
/*
* XXX: write a coherent comment on why we do this.
* See also: http://lkml.kernel.org/r/20111202010832.602203411@sbsiddha-desk.sc.intel.com
* If there is an imbalance between LLC domains (IOW we could
* increase the overall cache use), we need some less-loaded LLC
* domain to pull some load. Likewise, we may need to spread
* load within the current LLC domain (e.g. packed SMT cores but
* other CPUs are idle). We can't really know from here how busy
* the others are - so just get a nohz balance going if it looks
* like this LLC domain has tasks we could move.
*/
nr_busy = atomic_read(&sds->nr_busy_cpus);
if (nr_busy > 1) {
@ -9533,7 +9613,7 @@ static void nohz_balancer_kick(struct rq *rq)
sd = rcu_dereference(rq->sd);
if (sd) {
if ((rq->cfs.h_nr_running >= 1) &&
check_cpu_capacity(rq, sd)) {
check_cpu_capacity(rq, sd)) {
flags = NOHZ_KICK_MASK;
goto unlock;
}
@ -9541,11 +9621,7 @@ static void nohz_balancer_kick(struct rq *rq)
sd = rcu_dereference(per_cpu(sd_asym_packing, cpu));
if (sd) {
for_each_cpu(i, sched_domain_span(sd)) {
if (i == cpu ||
!cpumask_test_cpu(i, nohz.idle_cpus_mask))
continue;
for_each_cpu_and(i, sched_domain_span(sd), nohz.idle_cpus_mask) {
if (sched_asym_prefer(i, cpu)) {
flags = NOHZ_KICK_MASK;
goto unlock;
@ -10546,10 +10622,10 @@ const struct sched_class fair_sched_class = {
#ifdef CONFIG_SCHED_DEBUG
void print_cfs_stats(struct seq_file *m, int cpu)
{
struct cfs_rq *cfs_rq;
struct cfs_rq *cfs_rq, *pos;
rcu_read_lock();
for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq)
for_each_leaf_cfs_rq_safe(cpu_rq(cpu), cfs_rq, pos)
print_cfs_rq(m, cpu, cfs_rq);
rcu_read_unlock();
}

2
kernel/sched/isolation.c
View File

@ -80,7 +80,7 @@ static int __init housekeeping_setup(char *str, enum hk_flags flags)
cpumask_andnot(housekeeping_mask,
cpu_possible_mask, non_housekeeping_mask);
if (cpumask_empty(housekeeping_mask))
cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
__cpumask_set_cpu(smp_processor_id(), housekeeping_mask);
} else {
cpumask_var_t tmp;

45
kernel/sched/pelt.c
View File

@ -26,7 +26,6 @@
#include <linux/sched.h>
#include "sched.h"
#include "sched-pelt.h"
#include "pelt.h"
/*
@ -106,16 +105,12 @@ static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3)
* n=1
*/
static __always_inline u32
accumulate_sum(u64 delta, int cpu, struct sched_avg *sa,
accumulate_sum(u64 delta, struct sched_avg *sa,
unsigned long load, unsigned long runnable, int running)
{
unsigned long scale_freq, scale_cpu;
u32 contrib = (u32)delta; /* p == 0 -> delta < 1024 */
u64 periods;
scale_freq = arch_scale_freq_capacity(cpu);
scale_cpu = arch_scale_cpu_capacity(NULL, cpu);
delta += sa->period_contrib;
periods = delta / 1024; /* A period is 1024us (~1ms) */
@ -137,13 +132,12 @@ accumulate_sum(u64 delta, int cpu, struct sched_avg *sa,
}
sa->period_contrib = delta;
contrib = cap_scale(contrib, scale_freq);
if (load)
sa->load_sum += load * contrib;
if (runnable)
sa->runnable_load_sum += runnable * contrib;
if (running)
sa->util_sum += contrib * scale_cpu;
sa->util_sum += contrib << SCHED_CAPACITY_SHIFT;
return periods;
}
@ -177,7 +171,7 @@ accumulate_sum(u64 delta, int cpu, struct sched_avg *sa,
* = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}]
*/
static __always_inline int
___update_load_sum(u64 now, int cpu, struct sched_avg *sa,
___update_load_sum(u64 now, struct sched_avg *sa,
unsigned long load, unsigned long runnable, int running)
{
u64 delta;
@ -221,7 +215,7 @@ ___update_load_sum(u64 now, int cpu, struct sched_avg *sa,
* Step 1: accumulate *_sum since last_update_time. If we haven't
* crossed period boundaries, finish.
*/
if (!accumulate_sum(delta, cpu, sa, load, runnable, running))
if (!accumulate_sum(delta, sa, load, runnable, running))
return 0;
return 1;
@ -267,9 +261,9 @@ ___update_load_avg(struct sched_avg *sa, unsigned long load, unsigned long runna
* runnable_load_avg = \Sum se->avg.runable_load_avg
*/
int __update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se)
int __update_load_avg_blocked_se(u64 now, struct sched_entity *se)
{
if (___update_load_sum(now, cpu, &se->avg, 0, 0, 0)) {
if (___update_load_sum(now, &se->avg, 0, 0, 0)) {
___update_load_avg(&se->avg, se_weight(se), se_runnable(se));
return 1;
}
@ -277,9 +271,9 @@ int __update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se)
return 0;
}
int __update_load_avg_se(u64 now, int cpu, struct cfs_rq *cfs_rq, struct sched_entity *se)
int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se)
{
if (___update_load_sum(now, cpu, &se->avg, !!se->on_rq, !!se->on_rq,
if (___update_load_sum(now, &se->avg, !!se->on_rq, !!se->on_rq,
cfs_rq->curr == se)) {
___update_load_avg(&se->avg, se_weight(se), se_runnable(se));
@ -290,9 +284,9 @@ int __update_load_avg_se(u64 now, int cpu, struct cfs_rq *cfs_rq, struct sched_e
return 0;
}
int __update_load_avg_cfs_rq(u64 now, int cpu, struct cfs_rq *cfs_rq)
int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq)
{
if (___update_load_sum(now, cpu, &cfs_rq->avg,
if (___update_load_sum(now, &cfs_rq->avg,
scale_load_down(cfs_rq->load.weight),
scale_load_down(cfs_rq->runnable_weight),
cfs_rq->curr != NULL)) {
@ -317,7 +311,7 @@ int __update_load_avg_cfs_rq(u64 now, int cpu, struct cfs_rq *cfs_rq)
int update_rt_rq_load_avg(u64 now, struct rq *rq, int running)
{
if (___update_load_sum(now, rq->cpu, &rq->avg_rt,
if (___update_load_sum(now, &rq->avg_rt,
running,
running,
running)) {
@ -340,7 +334,7 @@ int update_rt_rq_load_avg(u64 now, struct rq *rq, int running)
int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
{
if (___update_load_sum(now, rq->cpu, &rq->avg_dl,
if (___update_load_sum(now, &rq->avg_dl,
running,
running,
running)) {
@ -365,22 +359,31 @@ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
int update_irq_load_avg(struct rq *rq, u64 running)
{
int ret = 0;
/*
* We can't use clock_pelt because irq time is not accounted in
* clock_task. Instead we directly scale the running time to
* reflect the real amount of computation
*/
running = cap_scale(running, arch_scale_freq_capacity(cpu_of(rq)));
running = cap_scale(running, arch_scale_cpu_capacity(NULL, cpu_of(rq)));
/*
* We know the time that has been used by interrupt since last update
* but we don't when. Let be pessimistic and assume that interrupt has
* happened just before the update. This is not so far from reality
* because interrupt will most probably wake up task and trig an update
* of rq clock during which the metric si updated.
* of rq clock during which the metric is updated.
* We start to decay with normal context time and then we add the
* interrupt context time.
* We can safely remove running from rq->clock because
* rq->clock += delta with delta >= running
*/
ret = ___update_load_sum(rq->clock - running, rq->cpu, &rq->avg_irq,
ret = ___update_load_sum(rq->clock - running, &rq->avg_irq,
0,
0,
0);
ret += ___update_load_sum(rq->clock, rq->cpu, &rq->avg_irq,
ret += ___update_load_sum(rq->clock, &rq->avg_irq,
1,
1,
1);

114
kernel/sched/pelt.h
View File

@ -1,8 +1,9 @@
#ifdef CONFIG_SMP
#include "sched-pelt.h"
int __update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se);
int __update_load_avg_se(u64 now, int cpu, struct cfs_rq *cfs_rq, struct sched_entity *se);
int __update_load_avg_cfs_rq(u64 now, int cpu, struct cfs_rq *cfs_rq);
int __update_load_avg_blocked_se(u64 now, struct sched_entity *se);
int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se);
int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
@ -42,6 +43,101 @@ static inline void cfs_se_util_change(struct sched_avg *avg)
WRITE_ONCE(avg->util_est.enqueued, enqueued);
}
/*
* The clock_pelt scales the time to reflect the effective amount of
* computation done during the running delta time but then sync back to
* clock_task when rq is idle.
*
*
* absolute time | 1| 2| 3| 4| 5| 6| 7| 8| 9|10|11|12|13|14|15|16
* @ max capacity ------******---------------******---------------
* @ half capacity ------************---------************---------
* clock pelt | 1| 2| 3| 4| 7| 8| 9| 10| 11|14|15|16
*
*/
static inline void update_rq_clock_pelt(struct rq *rq, s64 delta)
{
if (unlikely(is_idle_task(rq->curr))) {
/* The rq is idle, we can sync to clock_task */
rq->clock_pelt = rq_clock_task(rq);
return;
}
/*
* When a rq runs at a lower compute capacity, it will need
* more time to do the same amount of work than at max
* capacity. In order to be invariant, we scale the delta to
* reflect how much work has been really done.
* Running longer results in stealing idle time that will
* disturb the load signal compared to max capacity. This
* stolen idle time will be automatically reflected when the
* rq will be idle and the clock will be synced with
* rq_clock_task.
*/
/*
* Scale the elapsed time to reflect the real amount of
* computation
*/
delta = cap_scale(delta, arch_scale_cpu_capacity(NULL, cpu_of(rq)));
delta = cap_scale(delta, arch_scale_freq_capacity(cpu_of(rq)));
rq->clock_pelt += delta;
}
/*
* When rq becomes idle, we have to check if it has lost idle time
* because it was fully busy. A rq is fully used when the /Sum util_sum
* is greater or equal to:
* (LOAD_AVG_MAX - 1024 + rq->cfs.avg.period_contrib) << SCHED_CAPACITY_SHIFT;
* For optimization and computing rounding purpose, we don't take into account
* the position in the current window (period_contrib) and we use the higher
* bound of util_sum to decide.
*/
static inline void update_idle_rq_clock_pelt(struct rq *rq)
{
u32 divider = ((LOAD_AVG_MAX - 1024) << SCHED_CAPACITY_SHIFT) - LOAD_AVG_MAX;
u32 util_sum = rq->cfs.avg.util_sum;
util_sum += rq->avg_rt.util_sum;
util_sum += rq->avg_dl.util_sum;
/*
* Reflecting stolen time makes sense only if the idle
* phase would be present at max capacity. As soon as the
* utilization of a rq has reached the maximum value, it is
* considered as an always runnig rq without idle time to
* steal. This potential idle time is considered as lost in
* this case. We keep track of this lost idle time compare to
* rq's clock_task.
*/
if (util_sum >= divider)
rq->lost_idle_time += rq_clock_task(rq) - rq->clock_pelt;
}
static inline u64 rq_clock_pelt(struct rq *rq)
{
lockdep_assert_held(&rq->lock);
assert_clock_updated(rq);
return rq->clock_pelt - rq->lost_idle_time;
}
#ifdef CONFIG_CFS_BANDWIDTH
/* rq->task_clock normalized against any time this cfs_rq has spent throttled */
static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
{
if (unlikely(cfs_rq->throttle_count))
return cfs_rq->throttled_clock_task - cfs_rq->throttled_clock_task_time;
return rq_clock_pelt(rq_of(cfs_rq)) - cfs_rq->throttled_clock_task_time;
}
#else
static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
{
return rq_clock_pelt(rq_of(cfs_rq));
}
#endif
#else
static inline int
@ -67,6 +163,18 @@ update_irq_load_avg(struct rq *rq, u64 running)
{
return 0;
}
static inline u64 rq_clock_pelt(struct rq *rq)
{
return rq_clock_task(rq);
}
static inline void
update_rq_clock_pelt(struct rq *rq, s64 delta) { }
static inline void
update_idle_rq_clock_pelt(struct rq *rq) { }
#endif

6
kernel/sched/rt.c
View File

@ -1587,7 +1587,7 @@ pick_next_task_rt(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
* rt task
*/
if (rq->curr->sched_class != &rt_sched_class)
update_rt_rq_load_avg(rq_clock_task(rq), rq, 0);
update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 0);
return p;
}
@ -1596,7 +1596,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
{
update_curr_rt(rq);
update_rt_rq_load_avg(rq_clock_task(rq), rq, 1);
update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 1);
/*
* The previous task needs to be made eligible for pushing
@ -2325,7 +2325,7 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
struct sched_rt_entity *rt_se = &p->rt;
update_curr_rt(rq);
update_rt_rq_load_avg(rq_clock_task(rq), rq, 1);
update_rt_rq_load_avg(rq_clock_pelt(rq), rq, 1);
watchdog(rq, p);

58
kernel/sched/sched.h
View File

@ -861,7 +861,10 @@ struct rq {
unsigned int clock_update_flags;
u64 clock;
u64 clock_task;
/* Ensure that all clocks are in the same cache line */
u64 clock_task ____cacheline_aligned;
u64 clock_pelt;
unsigned long lost_idle_time;
atomic_t nr_iowait;
@ -951,6 +954,22 @@ struct rq {
#endif
};
#ifdef CONFIG_FAIR_GROUP_SCHED
/* CPU runqueue to which this cfs_rq is attached */
static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
{
return cfs_rq->rq;
}
#else
static inline struct rq *rq_of(struct cfs_rq *cfs_rq)
{
return container_of(cfs_rq, struct rq, cfs);
}
#endif
static inline int cpu_of(struct rq *rq)
{
#ifdef CONFIG_SMP
@ -1460,9 +1479,9 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
*/
smp_wmb();
#ifdef CONFIG_THREAD_INFO_IN_TASK
p->cpu = cpu;
WRITE_ONCE(p->cpu, cpu);
#else
task_thread_info(p)->cpu = cpu;
WRITE_ONCE(task_thread_info(p)->cpu, cpu);
#endif
p->wake_cpu = cpu;
#endif
@ -1563,7 +1582,7 @@ static inline int task_on_rq_queued(struct task_struct *p)
static inline int task_on_rq_migrating(struct task_struct *p)
{
return p->on_rq == TASK_ON_RQ_MIGRATING;
return READ_ONCE(p->on_rq) == TASK_ON_RQ_MIGRATING;
}
/*
@ -1781,7 +1800,7 @@ extern void init_dl_rq_bw_ratio(struct dl_rq *dl_rq);
unsigned long to_ratio(u64 period, u64 runtime);
extern void init_entity_runnable_average(struct sched_entity *se);
extern void post_init_entity_util_avg(struct sched_entity *se);
extern void post_init_entity_util_avg(struct task_struct *p);
#ifdef CONFIG_NO_HZ_FULL
extern bool sched_can_stop_tick(struct rq *rq);
@ -2211,6 +2230,13 @@ static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
# define arch_scale_freq_invariant() false
#endif
#ifdef CONFIG_SMP
static inline unsigned long capacity_orig_of(int cpu)
{
return cpu_rq(cpu)->cpu_capacity_orig;
}
#endif
#ifdef CONFIG_CPU_FREQ_GOV_SCHEDUTIL
/**
* enum schedutil_type - CPU utilization type
@ -2299,11 +2325,19 @@ unsigned long scale_irq_capacity(unsigned long util, unsigned long irq, unsigned
#endif
#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
#define perf_domain_span(pd) (to_cpumask(((pd)->em_pd->cpus)))
#else
#define perf_domain_span(pd) NULL
#endif
#ifdef CONFIG_SMP
extern struct static_key_false sched_energy_present;
#endif
#define perf_domain_span(pd) (to_cpumask(((pd)->em_pd->cpus)))
DECLARE_STATIC_KEY_FALSE(sched_energy_present);
static inline bool sched_energy_enabled(void)
{
return static_branch_unlikely(&sched_energy_present);
}
#else /* ! (CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL) */
#define perf_domain_span(pd) NULL
static inline bool sched_energy_enabled(void) { return false; }
#endif /* CONFIG_ENERGY_MODEL && CONFIG_CPU_FREQ_GOV_SCHEDUTIL */

33
kernel/sched/topology.c
View File

@ -201,11 +201,37 @@ sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
return 1;
}
DEFINE_STATIC_KEY_FALSE(sched_energy_present);
#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
DEFINE_STATIC_KEY_FALSE(sched_energy_present);
unsigned int sysctl_sched_energy_aware = 1;
DEFINE_MUTEX(sched_energy_mutex);
bool sched_energy_update;
#ifdef CONFIG_PROC_SYSCTL
int sched_energy_aware_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
int ret, state;
if (write && !capable(CAP_SYS_ADMIN))
return -EPERM;
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (!ret && write) {
state = static_branch_unlikely(&sched_energy_present);
if (state != sysctl_sched_energy_aware) {
mutex_lock(&sched_energy_mutex);
sched_energy_update = 1;
rebuild_sched_domains();
sched_energy_update = 0;
mutex_unlock(&sched_energy_mutex);
}
}
return ret;
}
#endif
static void free_pd(struct perf_domain *pd)
{
struct perf_domain *tmp;
@ -322,6 +348,9 @@ static bool build_perf_domains(const struct cpumask *cpu_map)
struct cpufreq_policy *policy;
struct cpufreq_governor *gov;
if (!sysctl_sched_energy_aware)
goto free;
/* EAS is enabled for asymmetric CPU capacity topologies. */
if (!per_cpu(sd_asym_cpucapacity, cpu)) {
if (sched_debug()) {
@ -676,7 +705,7 @@ cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
}
struct s_data {
struct sched_domain ** __percpu sd;
struct sched_domain * __percpu *sd;
struct root_domain *rd;
};

11
kernel/sysctl.c
View File

@ -472,6 +472,17 @@ static struct ctl_table kern_table[] = {
.extra1 = &one,
},
#endif
#if defined(CONFIG_ENERGY_MODEL) && defined(CONFIG_CPU_FREQ_GOV_SCHEDUTIL)
{
.procname = "sched_energy_aware",
.data = &sysctl_sched_energy_aware,
.maxlen = sizeof(unsigned int),
.mode = 0644,
.proc_handler = sched_energy_aware_handler,
.extra1 = &zero,
.extra2 = &one,
},
#endif
#ifdef CONFIG_PROVE_LOCKING
{
.procname = "prove_locking",