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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-09-04 01:49:36 +00:00
![Linus Torvalds](/assets/img/avatar_default.png)
static priority level knowledge from non-scheduler code. The three APIs for non-scheduler code to set SCHED_FIFO are: - sched_set_fifo() - sched_set_fifo_low() - sched_set_normal() These are two FIFO priority levels: default (high), and a 'low' priority level, plus sched_set_normal() to set the policy back to non-SCHED_FIFO. Since the changes affect a lot of non-scheduler code, we kept this in a separate tree. When merging to the latest upstream tree there's a conflict in drivers/spi/spi.c, which can be resolved via: sched_set_fifo(ctlr->kworker_task); Signed-off-by: Ingo Molnar <mingo@kernel.org> -----BEGIN PGP SIGNATURE----- iQJFBAABCgAvFiEEBpT5eoXrXCwVQwEKEnMQ0APhK1gFAl8pPQIRHG1pbmdvQGtl cm5lbC5vcmcACgkQEnMQ0APhK1j0Jw/+LlSyX6gD2ATy3cizGL7DFPZogD5MVKTb IXbhXH/ACpuPQlBe1+haRLbJj6XfXqbOlAleVKt7eh+jZ1jYjC972RCSTO4566mJ 0v8Iy9kkEeb2TDbYx1H3bnk78lf85t0CB+sCzyKUYFuTrXU04eRj7MtN3vAQyRQU xJg83x/sT5DGdDTP50sL7lpbwk3INWkD0aDCJEaO/a9yHElMsTZiZBKoXxN/s30o FsfzW56jqtng771H2bo8ERN7+abwJg10crQU5mIaLhacNMETuz0NZ/f8fY/fydCL Ju8HAdNKNXyphWkAOmixQuyYtWKe2/GfbHg8hld0jmpwxkOSTgZjY+pFcv7/w306 g2l1TPOt8e1n5jbfnY3eig+9Kr8y0qHkXPfLfgRqKwMMaOqTTYixEzj+NdxEIRX9 Kr7oFAv6VEFfXGSpb5L1qyjIGVgQ5/JE/p3OC3GHEsw5VKiy5yjhNLoSmSGzdS61 1YurVvypSEUAn3DqTXgeGX76f0HH365fIKqmbFrUWxliF+YyflMhtrj2JFtejGzH Md3RgAzxusE9S6k3gw1ev4byh167bPBbY8jz0w3Gd7IBRKy9vo92h6ZRYIl6xeoC BU2To1IhCAydIr6hNsIiCSDTgiLbsYQzPuVVovUxNh+l1ZvKV2X+csEHhs8oW4pr 4BRU7dKL2NE= =/7JH -----END PGP SIGNATURE----- Merge tag 'sched-fifo-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull sched/fifo updates from Ingo Molnar: "This adds the sched_set_fifo*() encapsulation APIs to remove static priority level knowledge from non-scheduler code. The three APIs for non-scheduler code to set SCHED_FIFO are: - sched_set_fifo() - sched_set_fifo_low() - sched_set_normal() These are two FIFO priority levels: default (high), and a 'low' priority level, plus sched_set_normal() to set the policy back to non-SCHED_FIFO. Since the changes affect a lot of non-scheduler code, we kept this in a separate tree" * tag 'sched-fifo-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits) sched,tracing: Convert to sched_set_fifo() sched: Remove sched_set_*() return value sched: Remove sched_setscheduler*() EXPORTs sched,psi: Convert to sched_set_fifo_low() sched,rcutorture: Convert to sched_set_fifo_low() sched,rcuperf: Convert to sched_set_fifo_low() sched,locktorture: Convert to sched_set_fifo() sched,irq: Convert to sched_set_fifo() sched,watchdog: Convert to sched_set_fifo() sched,serial: Convert to sched_set_fifo() sched,powerclamp: Convert to sched_set_fifo() sched,ion: Convert to sched_set_normal() sched,powercap: Convert to sched_set_fifo*() sched,spi: Convert to sched_set_fifo*() sched,mmc: Convert to sched_set_fifo*() sched,ivtv: Convert to sched_set_fifo*() sched,drm/scheduler: Convert to sched_set_fifo*() sched,msm: Convert to sched_set_fifo*() sched,psci: Convert to sched_set_fifo*() sched,drbd: Convert to sched_set_fifo*() ...
492 lines
12 KiB
C
492 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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*
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* Copyright (C) 2016 ARM Limited
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/atomic.h>
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#include <linux/completion.h>
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#include <linux/cpu.h>
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#include <linux/cpuidle.h>
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#include <linux/cpu_pm.h>
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#include <linux/kernel.h>
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#include <linux/kthread.h>
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#include <uapi/linux/sched/types.h>
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#include <linux/module.h>
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#include <linux/preempt.h>
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#include <linux/psci.h>
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#include <linux/slab.h>
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#include <linux/tick.h>
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#include <linux/topology.h>
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#include <asm/cpuidle.h>
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#include <uapi/linux/psci.h>
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#define NUM_SUSPEND_CYCLE (10)
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static unsigned int nb_available_cpus;
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static int tos_resident_cpu = -1;
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static atomic_t nb_active_threads;
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static struct completion suspend_threads_started =
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COMPLETION_INITIALIZER(suspend_threads_started);
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static struct completion suspend_threads_done =
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COMPLETION_INITIALIZER(suspend_threads_done);
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/*
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* We assume that PSCI operations are used if they are available. This is not
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* necessarily true on arm64, since the decision is based on the
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* "enable-method" property of each CPU in the DT, but given that there is no
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* arch-specific way to check this, we assume that the DT is sensible.
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*/
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static int psci_ops_check(void)
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{
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int migrate_type = -1;
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int cpu;
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if (!(psci_ops.cpu_off && psci_ops.cpu_on && psci_ops.cpu_suspend)) {
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pr_warn("Missing PSCI operations, aborting tests\n");
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return -EOPNOTSUPP;
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}
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if (psci_ops.migrate_info_type)
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migrate_type = psci_ops.migrate_info_type();
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if (migrate_type == PSCI_0_2_TOS_UP_MIGRATE ||
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migrate_type == PSCI_0_2_TOS_UP_NO_MIGRATE) {
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/* There is a UP Trusted OS, find on which core it resides. */
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for_each_online_cpu(cpu)
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if (psci_tos_resident_on(cpu)) {
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tos_resident_cpu = cpu;
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break;
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}
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if (tos_resident_cpu == -1)
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pr_warn("UP Trusted OS resides on no online CPU\n");
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}
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return 0;
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}
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/*
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* offlined_cpus is a temporary array but passing it as an argument avoids
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* multiple allocations.
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*/
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static unsigned int down_and_up_cpus(const struct cpumask *cpus,
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struct cpumask *offlined_cpus)
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{
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int cpu;
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int err = 0;
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cpumask_clear(offlined_cpus);
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/* Try to power down all CPUs in the mask. */
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for_each_cpu(cpu, cpus) {
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int ret = remove_cpu(cpu);
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/*
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* cpu_down() checks the number of online CPUs before the TOS
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* resident CPU.
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*/
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if (cpumask_weight(offlined_cpus) + 1 == nb_available_cpus) {
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if (ret != -EBUSY) {
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pr_err("Unexpected return code %d while trying "
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"to power down last online CPU %d\n",
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ret, cpu);
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++err;
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}
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} else if (cpu == tos_resident_cpu) {
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if (ret != -EPERM) {
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pr_err("Unexpected return code %d while trying "
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"to power down TOS resident CPU %d\n",
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ret, cpu);
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++err;
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}
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} else if (ret != 0) {
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pr_err("Error occurred (%d) while trying "
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"to power down CPU %d\n", ret, cpu);
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++err;
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}
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if (ret == 0)
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cpumask_set_cpu(cpu, offlined_cpus);
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}
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/* Try to power up all the CPUs that have been offlined. */
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for_each_cpu(cpu, offlined_cpus) {
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int ret = add_cpu(cpu);
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if (ret != 0) {
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pr_err("Error occurred (%d) while trying "
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"to power up CPU %d\n", ret, cpu);
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++err;
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} else {
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cpumask_clear_cpu(cpu, offlined_cpus);
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}
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}
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/*
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* Something went bad at some point and some CPUs could not be turned
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* back on.
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*/
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WARN_ON(!cpumask_empty(offlined_cpus) ||
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num_online_cpus() != nb_available_cpus);
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return err;
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}
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static void free_cpu_groups(int num, cpumask_var_t **pcpu_groups)
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{
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int i;
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cpumask_var_t *cpu_groups = *pcpu_groups;
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for (i = 0; i < num; ++i)
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free_cpumask_var(cpu_groups[i]);
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kfree(cpu_groups);
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}
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static int alloc_init_cpu_groups(cpumask_var_t **pcpu_groups)
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{
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int num_groups = 0;
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cpumask_var_t tmp, *cpu_groups;
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if (!alloc_cpumask_var(&tmp, GFP_KERNEL))
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return -ENOMEM;
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cpu_groups = kcalloc(nb_available_cpus, sizeof(cpu_groups),
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GFP_KERNEL);
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if (!cpu_groups) {
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free_cpumask_var(tmp);
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return -ENOMEM;
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}
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cpumask_copy(tmp, cpu_online_mask);
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while (!cpumask_empty(tmp)) {
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const struct cpumask *cpu_group =
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topology_core_cpumask(cpumask_any(tmp));
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if (!alloc_cpumask_var(&cpu_groups[num_groups], GFP_KERNEL)) {
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free_cpumask_var(tmp);
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free_cpu_groups(num_groups, &cpu_groups);
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return -ENOMEM;
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}
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cpumask_copy(cpu_groups[num_groups++], cpu_group);
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cpumask_andnot(tmp, tmp, cpu_group);
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}
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free_cpumask_var(tmp);
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*pcpu_groups = cpu_groups;
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return num_groups;
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}
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static int hotplug_tests(void)
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{
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int i, nb_cpu_group, err = -ENOMEM;
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cpumask_var_t offlined_cpus, *cpu_groups;
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char *page_buf;
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if (!alloc_cpumask_var(&offlined_cpus, GFP_KERNEL))
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return err;
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nb_cpu_group = alloc_init_cpu_groups(&cpu_groups);
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if (nb_cpu_group < 0)
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goto out_free_cpus;
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page_buf = (char *)__get_free_page(GFP_KERNEL);
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if (!page_buf)
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goto out_free_cpu_groups;
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/*
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* Of course the last CPU cannot be powered down and cpu_down() should
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* refuse doing that.
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*/
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pr_info("Trying to turn off and on again all CPUs\n");
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err = down_and_up_cpus(cpu_online_mask, offlined_cpus);
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/*
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* Take down CPUs by cpu group this time. When the last CPU is turned
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* off, the cpu group itself should shut down.
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*/
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for (i = 0; i < nb_cpu_group; ++i) {
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ssize_t len = cpumap_print_to_pagebuf(true, page_buf,
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cpu_groups[i]);
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/* Remove trailing newline. */
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page_buf[len - 1] = '\0';
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pr_info("Trying to turn off and on again group %d (CPUs %s)\n",
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i, page_buf);
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err += down_and_up_cpus(cpu_groups[i], offlined_cpus);
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}
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free_page((unsigned long)page_buf);
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out_free_cpu_groups:
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free_cpu_groups(nb_cpu_group, &cpu_groups);
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out_free_cpus:
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free_cpumask_var(offlined_cpus);
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return err;
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}
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static void dummy_callback(struct timer_list *unused) {}
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static int suspend_cpu(struct cpuidle_device *dev,
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struct cpuidle_driver *drv, int index)
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{
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struct cpuidle_state *state = &drv->states[index];
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bool broadcast = state->flags & CPUIDLE_FLAG_TIMER_STOP;
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int ret;
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arch_cpu_idle_enter();
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if (broadcast) {
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/*
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* The local timer will be shut down, we need to enter tick
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* broadcast.
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*/
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ret = tick_broadcast_enter();
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if (ret) {
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/*
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* In the absence of hardware broadcast mechanism,
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* this CPU might be used to broadcast wakeups, which
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* may be why entering tick broadcast has failed.
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* There is little the kernel can do to work around
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* that, so enter WFI instead (idle state 0).
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*/
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cpu_do_idle();
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ret = 0;
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goto out_arch_exit;
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}
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}
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ret = state->enter(dev, drv, index);
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if (broadcast)
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tick_broadcast_exit();
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out_arch_exit:
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arch_cpu_idle_exit();
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return ret;
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}
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static int suspend_test_thread(void *arg)
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{
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int cpu = (long)arg;
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int i, nb_suspend = 0, nb_shallow_sleep = 0, nb_err = 0;
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struct cpuidle_device *dev;
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struct cpuidle_driver *drv;
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/* No need for an actual callback, we just want to wake up the CPU. */
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struct timer_list wakeup_timer;
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/* Wait for the main thread to give the start signal. */
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wait_for_completion(&suspend_threads_started);
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/* Set maximum priority to preempt all other threads on this CPU. */
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sched_set_fifo(current);
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dev = this_cpu_read(cpuidle_devices);
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drv = cpuidle_get_cpu_driver(dev);
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pr_info("CPU %d entering suspend cycles, states 1 through %d\n",
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cpu, drv->state_count - 1);
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timer_setup_on_stack(&wakeup_timer, dummy_callback, 0);
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for (i = 0; i < NUM_SUSPEND_CYCLE; ++i) {
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int index;
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/*
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* Test all possible states, except 0 (which is usually WFI and
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* doesn't use PSCI).
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*/
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for (index = 1; index < drv->state_count; ++index) {
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int ret;
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struct cpuidle_state *state = &drv->states[index];
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/*
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* Set the timer to wake this CPU up in some time (which
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* should be largely sufficient for entering suspend).
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* If the local tick is disabled when entering suspend,
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* suspend_cpu() takes care of switching to a broadcast
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* tick, so the timer will still wake us up.
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*/
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mod_timer(&wakeup_timer, jiffies +
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usecs_to_jiffies(state->target_residency));
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/* IRQs must be disabled during suspend operations. */
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local_irq_disable();
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ret = suspend_cpu(dev, drv, index);
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/*
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* We have woken up. Re-enable IRQs to handle any
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* pending interrupt, do not wait until the end of the
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* loop.
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*/
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local_irq_enable();
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if (ret == index) {
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++nb_suspend;
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} else if (ret >= 0) {
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/* We did not enter the expected state. */
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++nb_shallow_sleep;
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} else {
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pr_err("Failed to suspend CPU %d: error %d "
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"(requested state %d, cycle %d)\n",
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cpu, ret, index, i);
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++nb_err;
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}
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}
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}
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/*
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* Disable the timer to make sure that the timer will not trigger
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* later.
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*/
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del_timer(&wakeup_timer);
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destroy_timer_on_stack(&wakeup_timer);
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if (atomic_dec_return_relaxed(&nb_active_threads) == 0)
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complete(&suspend_threads_done);
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for (;;) {
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/* Needs to be set first to avoid missing a wakeup. */
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set_current_state(TASK_INTERRUPTIBLE);
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if (kthread_should_park())
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break;
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schedule();
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}
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pr_info("CPU %d suspend test results: success %d, shallow states %d, errors %d\n",
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cpu, nb_suspend, nb_shallow_sleep, nb_err);
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kthread_parkme();
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return nb_err;
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}
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static int suspend_tests(void)
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{
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int i, cpu, err = 0;
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struct task_struct **threads;
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int nb_threads = 0;
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threads = kmalloc_array(nb_available_cpus, sizeof(*threads),
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GFP_KERNEL);
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if (!threads)
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return -ENOMEM;
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/*
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* Stop cpuidle to prevent the idle tasks from entering a deep sleep
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* mode, as it might interfere with the suspend threads on other CPUs.
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* This does not prevent the suspend threads from using cpuidle (only
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* the idle tasks check this status). Take the idle lock so that
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* the cpuidle driver and device look-up can be carried out safely.
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*/
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cpuidle_pause_and_lock();
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for_each_online_cpu(cpu) {
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struct task_struct *thread;
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/* Check that cpuidle is available on that CPU. */
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struct cpuidle_device *dev = per_cpu(cpuidle_devices, cpu);
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struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
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if (!dev || !drv) {
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pr_warn("cpuidle not available on CPU %d, ignoring\n",
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cpu);
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continue;
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}
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thread = kthread_create_on_cpu(suspend_test_thread,
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(void *)(long)cpu, cpu,
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"psci_suspend_test");
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if (IS_ERR(thread))
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pr_err("Failed to create kthread on CPU %d\n", cpu);
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else
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threads[nb_threads++] = thread;
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}
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if (nb_threads < 1) {
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err = -ENODEV;
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goto out;
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}
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atomic_set(&nb_active_threads, nb_threads);
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/*
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* Wake up the suspend threads. To avoid the main thread being preempted
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* before all the threads have been unparked, the suspend threads will
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* wait for the completion of suspend_threads_started.
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*/
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for (i = 0; i < nb_threads; ++i)
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wake_up_process(threads[i]);
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complete_all(&suspend_threads_started);
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wait_for_completion(&suspend_threads_done);
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/* Stop and destroy all threads, get return status. */
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for (i = 0; i < nb_threads; ++i) {
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err += kthread_park(threads[i]);
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err += kthread_stop(threads[i]);
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}
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out:
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cpuidle_resume_and_unlock();
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kfree(threads);
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return err;
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}
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static int __init psci_checker(void)
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{
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int ret;
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/*
|
|
* Since we're in an initcall, we assume that all the CPUs that all
|
|
* CPUs that can be onlined have been onlined.
|
|
*
|
|
* The tests assume that hotplug is enabled but nobody else is using it,
|
|
* otherwise the results will be unpredictable. However, since there
|
|
* is no userspace yet in initcalls, that should be fine, as long as
|
|
* no torture test is running at the same time (see Kconfig).
|
|
*/
|
|
nb_available_cpus = num_online_cpus();
|
|
|
|
/* Check PSCI operations are set up and working. */
|
|
ret = psci_ops_check();
|
|
if (ret)
|
|
return ret;
|
|
|
|
pr_info("PSCI checker started using %u CPUs\n", nb_available_cpus);
|
|
|
|
pr_info("Starting hotplug tests\n");
|
|
ret = hotplug_tests();
|
|
if (ret == 0)
|
|
pr_info("Hotplug tests passed OK\n");
|
|
else if (ret > 0)
|
|
pr_err("%d error(s) encountered in hotplug tests\n", ret);
|
|
else {
|
|
pr_err("Out of memory\n");
|
|
return ret;
|
|
}
|
|
|
|
pr_info("Starting suspend tests (%d cycles per state)\n",
|
|
NUM_SUSPEND_CYCLE);
|
|
ret = suspend_tests();
|
|
if (ret == 0)
|
|
pr_info("Suspend tests passed OK\n");
|
|
else if (ret > 0)
|
|
pr_err("%d error(s) encountered in suspend tests\n", ret);
|
|
else {
|
|
switch (ret) {
|
|
case -ENOMEM:
|
|
pr_err("Out of memory\n");
|
|
break;
|
|
case -ENODEV:
|
|
pr_warn("Could not start suspend tests on any CPU\n");
|
|
break;
|
|
}
|
|
}
|
|
|
|
pr_info("PSCI checker completed\n");
|
|
return ret < 0 ? ret : 0;
|
|
}
|
|
late_initcall(psci_checker);
|