summaryrefslogtreecommitdiffstats
path: root/kernel/rcu/rcuscale.c
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/rcu/rcuscale.c')
-rw-r--r--kernel/rcu/rcuscale.c1058
1 files changed, 1058 insertions, 0 deletions
diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
new file mode 100644
index 0000000000..ffdb30495e
--- /dev/null
+++ b/kernel/rcu/rcuscale.c
@@ -0,0 +1,1058 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Read-Copy Update module-based scalability-test facility
+ *
+ * Copyright (C) IBM Corporation, 2015
+ *
+ * Authors: Paul E. McKenney <paulmck@linux.ibm.com>
+ */
+
+#define pr_fmt(fmt) fmt
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/kthread.h>
+#include <linux/err.h>
+#include <linux/spinlock.h>
+#include <linux/smp.h>
+#include <linux/rcupdate.h>
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <uapi/linux/sched/types.h>
+#include <linux/atomic.h>
+#include <linux/bitops.h>
+#include <linux/completion.h>
+#include <linux/moduleparam.h>
+#include <linux/percpu.h>
+#include <linux/notifier.h>
+#include <linux/reboot.h>
+#include <linux/freezer.h>
+#include <linux/cpu.h>
+#include <linux/delay.h>
+#include <linux/stat.h>
+#include <linux/srcu.h>
+#include <linux/slab.h>
+#include <asm/byteorder.h>
+#include <linux/torture.h>
+#include <linux/vmalloc.h>
+#include <linux/rcupdate_trace.h>
+
+#include "rcu.h"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Paul E. McKenney <paulmck@linux.ibm.com>");
+
+#define SCALE_FLAG "-scale:"
+#define SCALEOUT_STRING(s) \
+ pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s)
+#define VERBOSE_SCALEOUT_STRING(s) \
+ do { if (verbose) pr_alert("%s" SCALE_FLAG " %s\n", scale_type, s); } while (0)
+#define SCALEOUT_ERRSTRING(s) \
+ pr_alert("%s" SCALE_FLAG "!!! %s\n", scale_type, s)
+
+/*
+ * The intended use cases for the nreaders and nwriters module parameters
+ * are as follows:
+ *
+ * 1. Specify only the nr_cpus kernel boot parameter. This will
+ * set both nreaders and nwriters to the value specified by
+ * nr_cpus for a mixed reader/writer test.
+ *
+ * 2. Specify the nr_cpus kernel boot parameter, but set
+ * rcuscale.nreaders to zero. This will set nwriters to the
+ * value specified by nr_cpus for an update-only test.
+ *
+ * 3. Specify the nr_cpus kernel boot parameter, but set
+ * rcuscale.nwriters to zero. This will set nreaders to the
+ * value specified by nr_cpus for a read-only test.
+ *
+ * Various other use cases may of course be specified.
+ *
+ * Note that this test's readers are intended only as a test load for
+ * the writers. The reader scalability statistics will be overly
+ * pessimistic due to the per-critical-section interrupt disabling,
+ * test-end checks, and the pair of calls through pointers.
+ */
+
+#ifdef MODULE
+# define RCUSCALE_SHUTDOWN 0
+#else
+# define RCUSCALE_SHUTDOWN 1
+#endif
+
+torture_param(bool, gp_async, false, "Use asynchronous GP wait primitives");
+torture_param(int, gp_async_max, 1000, "Max # outstanding waits per writer");
+torture_param(bool, gp_exp, false, "Use expedited GP wait primitives");
+torture_param(int, holdoff, 10, "Holdoff time before test start (s)");
+torture_param(int, minruntime, 0, "Minimum run time (s)");
+torture_param(int, nreaders, -1, "Number of RCU reader threads");
+torture_param(int, nwriters, -1, "Number of RCU updater threads");
+torture_param(bool, shutdown, RCUSCALE_SHUTDOWN,
+ "Shutdown at end of scalability tests.");
+torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
+torture_param(int, writer_holdoff, 0, "Holdoff (us) between GPs, zero to disable");
+torture_param(int, writer_holdoff_jiffies, 0, "Holdoff (jiffies) between GPs, zero to disable");
+torture_param(int, kfree_rcu_test, 0, "Do we run a kfree_rcu() scale test?");
+torture_param(int, kfree_mult, 1, "Multiple of kfree_obj size to allocate.");
+torture_param(int, kfree_by_call_rcu, 0, "Use call_rcu() to emulate kfree_rcu()?");
+
+static char *scale_type = "rcu";
+module_param(scale_type, charp, 0444);
+MODULE_PARM_DESC(scale_type, "Type of RCU to scalability-test (rcu, srcu, ...)");
+
+static int nrealreaders;
+static int nrealwriters;
+static struct task_struct **writer_tasks;
+static struct task_struct **reader_tasks;
+static struct task_struct *shutdown_task;
+
+static u64 **writer_durations;
+static int *writer_n_durations;
+static atomic_t n_rcu_scale_reader_started;
+static atomic_t n_rcu_scale_writer_started;
+static atomic_t n_rcu_scale_writer_finished;
+static wait_queue_head_t shutdown_wq;
+static u64 t_rcu_scale_writer_started;
+static u64 t_rcu_scale_writer_finished;
+static unsigned long b_rcu_gp_test_started;
+static unsigned long b_rcu_gp_test_finished;
+static DEFINE_PER_CPU(atomic_t, n_async_inflight);
+
+#define MAX_MEAS 10000
+#define MIN_MEAS 100
+
+/*
+ * Operations vector for selecting different types of tests.
+ */
+
+struct rcu_scale_ops {
+ int ptype;
+ void (*init)(void);
+ void (*cleanup)(void);
+ int (*readlock)(void);
+ void (*readunlock)(int idx);
+ unsigned long (*get_gp_seq)(void);
+ unsigned long (*gp_diff)(unsigned long new, unsigned long old);
+ unsigned long (*exp_completed)(void);
+ void (*async)(struct rcu_head *head, rcu_callback_t func);
+ void (*gp_barrier)(void);
+ void (*sync)(void);
+ void (*exp_sync)(void);
+ struct task_struct *(*rso_gp_kthread)(void);
+ const char *name;
+};
+
+static struct rcu_scale_ops *cur_ops;
+
+/*
+ * Definitions for rcu scalability testing.
+ */
+
+static int rcu_scale_read_lock(void) __acquires(RCU)
+{
+ rcu_read_lock();
+ return 0;
+}
+
+static void rcu_scale_read_unlock(int idx) __releases(RCU)
+{
+ rcu_read_unlock();
+}
+
+static unsigned long __maybe_unused rcu_no_completed(void)
+{
+ return 0;
+}
+
+static void rcu_sync_scale_init(void)
+{
+}
+
+static struct rcu_scale_ops rcu_ops = {
+ .ptype = RCU_FLAVOR,
+ .init = rcu_sync_scale_init,
+ .readlock = rcu_scale_read_lock,
+ .readunlock = rcu_scale_read_unlock,
+ .get_gp_seq = rcu_get_gp_seq,
+ .gp_diff = rcu_seq_diff,
+ .exp_completed = rcu_exp_batches_completed,
+ .async = call_rcu_hurry,
+ .gp_barrier = rcu_barrier,
+ .sync = synchronize_rcu,
+ .exp_sync = synchronize_rcu_expedited,
+ .name = "rcu"
+};
+
+/*
+ * Definitions for srcu scalability testing.
+ */
+
+DEFINE_STATIC_SRCU(srcu_ctl_scale);
+static struct srcu_struct *srcu_ctlp = &srcu_ctl_scale;
+
+static int srcu_scale_read_lock(void) __acquires(srcu_ctlp)
+{
+ return srcu_read_lock(srcu_ctlp);
+}
+
+static void srcu_scale_read_unlock(int idx) __releases(srcu_ctlp)
+{
+ srcu_read_unlock(srcu_ctlp, idx);
+}
+
+static unsigned long srcu_scale_completed(void)
+{
+ return srcu_batches_completed(srcu_ctlp);
+}
+
+static void srcu_call_rcu(struct rcu_head *head, rcu_callback_t func)
+{
+ call_srcu(srcu_ctlp, head, func);
+}
+
+static void srcu_rcu_barrier(void)
+{
+ srcu_barrier(srcu_ctlp);
+}
+
+static void srcu_scale_synchronize(void)
+{
+ synchronize_srcu(srcu_ctlp);
+}
+
+static void srcu_scale_synchronize_expedited(void)
+{
+ synchronize_srcu_expedited(srcu_ctlp);
+}
+
+static struct rcu_scale_ops srcu_ops = {
+ .ptype = SRCU_FLAVOR,
+ .init = rcu_sync_scale_init,
+ .readlock = srcu_scale_read_lock,
+ .readunlock = srcu_scale_read_unlock,
+ .get_gp_seq = srcu_scale_completed,
+ .gp_diff = rcu_seq_diff,
+ .exp_completed = srcu_scale_completed,
+ .async = srcu_call_rcu,
+ .gp_barrier = srcu_rcu_barrier,
+ .sync = srcu_scale_synchronize,
+ .exp_sync = srcu_scale_synchronize_expedited,
+ .name = "srcu"
+};
+
+static struct srcu_struct srcud;
+
+static void srcu_sync_scale_init(void)
+{
+ srcu_ctlp = &srcud;
+ init_srcu_struct(srcu_ctlp);
+}
+
+static void srcu_sync_scale_cleanup(void)
+{
+ cleanup_srcu_struct(srcu_ctlp);
+}
+
+static struct rcu_scale_ops srcud_ops = {
+ .ptype = SRCU_FLAVOR,
+ .init = srcu_sync_scale_init,
+ .cleanup = srcu_sync_scale_cleanup,
+ .readlock = srcu_scale_read_lock,
+ .readunlock = srcu_scale_read_unlock,
+ .get_gp_seq = srcu_scale_completed,
+ .gp_diff = rcu_seq_diff,
+ .exp_completed = srcu_scale_completed,
+ .async = srcu_call_rcu,
+ .gp_barrier = srcu_rcu_barrier,
+ .sync = srcu_scale_synchronize,
+ .exp_sync = srcu_scale_synchronize_expedited,
+ .name = "srcud"
+};
+
+#ifdef CONFIG_TASKS_RCU
+
+/*
+ * Definitions for RCU-tasks scalability testing.
+ */
+
+static int tasks_scale_read_lock(void)
+{
+ return 0;
+}
+
+static void tasks_scale_read_unlock(int idx)
+{
+}
+
+static struct rcu_scale_ops tasks_ops = {
+ .ptype = RCU_TASKS_FLAVOR,
+ .init = rcu_sync_scale_init,
+ .readlock = tasks_scale_read_lock,
+ .readunlock = tasks_scale_read_unlock,
+ .get_gp_seq = rcu_no_completed,
+ .gp_diff = rcu_seq_diff,
+ .async = call_rcu_tasks,
+ .gp_barrier = rcu_barrier_tasks,
+ .sync = synchronize_rcu_tasks,
+ .exp_sync = synchronize_rcu_tasks,
+ .rso_gp_kthread = get_rcu_tasks_gp_kthread,
+ .name = "tasks"
+};
+
+#define TASKS_OPS &tasks_ops,
+
+#else // #ifdef CONFIG_TASKS_RCU
+
+#define TASKS_OPS
+
+#endif // #else // #ifdef CONFIG_TASKS_RCU
+
+#ifdef CONFIG_TASKS_RUDE_RCU
+
+/*
+ * Definitions for RCU-tasks-rude scalability testing.
+ */
+
+static int tasks_rude_scale_read_lock(void)
+{
+ return 0;
+}
+
+static void tasks_rude_scale_read_unlock(int idx)
+{
+}
+
+static struct rcu_scale_ops tasks_rude_ops = {
+ .ptype = RCU_TASKS_RUDE_FLAVOR,
+ .init = rcu_sync_scale_init,
+ .readlock = tasks_rude_scale_read_lock,
+ .readunlock = tasks_rude_scale_read_unlock,
+ .get_gp_seq = rcu_no_completed,
+ .gp_diff = rcu_seq_diff,
+ .async = call_rcu_tasks_rude,
+ .gp_barrier = rcu_barrier_tasks_rude,
+ .sync = synchronize_rcu_tasks_rude,
+ .exp_sync = synchronize_rcu_tasks_rude,
+ .rso_gp_kthread = get_rcu_tasks_rude_gp_kthread,
+ .name = "tasks-rude"
+};
+
+#define TASKS_RUDE_OPS &tasks_rude_ops,
+
+#else // #ifdef CONFIG_TASKS_RUDE_RCU
+
+#define TASKS_RUDE_OPS
+
+#endif // #else // #ifdef CONFIG_TASKS_RUDE_RCU
+
+#ifdef CONFIG_TASKS_TRACE_RCU
+
+/*
+ * Definitions for RCU-tasks-trace scalability testing.
+ */
+
+static int tasks_trace_scale_read_lock(void)
+{
+ rcu_read_lock_trace();
+ return 0;
+}
+
+static void tasks_trace_scale_read_unlock(int idx)
+{
+ rcu_read_unlock_trace();
+}
+
+static struct rcu_scale_ops tasks_tracing_ops = {
+ .ptype = RCU_TASKS_FLAVOR,
+ .init = rcu_sync_scale_init,
+ .readlock = tasks_trace_scale_read_lock,
+ .readunlock = tasks_trace_scale_read_unlock,
+ .get_gp_seq = rcu_no_completed,
+ .gp_diff = rcu_seq_diff,
+ .async = call_rcu_tasks_trace,
+ .gp_barrier = rcu_barrier_tasks_trace,
+ .sync = synchronize_rcu_tasks_trace,
+ .exp_sync = synchronize_rcu_tasks_trace,
+ .rso_gp_kthread = get_rcu_tasks_trace_gp_kthread,
+ .name = "tasks-tracing"
+};
+
+#define TASKS_TRACING_OPS &tasks_tracing_ops,
+
+#else // #ifdef CONFIG_TASKS_TRACE_RCU
+
+#define TASKS_TRACING_OPS
+
+#endif // #else // #ifdef CONFIG_TASKS_TRACE_RCU
+
+static unsigned long rcuscale_seq_diff(unsigned long new, unsigned long old)
+{
+ if (!cur_ops->gp_diff)
+ return new - old;
+ return cur_ops->gp_diff(new, old);
+}
+
+/*
+ * If scalability tests complete, wait for shutdown to commence.
+ */
+static void rcu_scale_wait_shutdown(void)
+{
+ cond_resched_tasks_rcu_qs();
+ if (atomic_read(&n_rcu_scale_writer_finished) < nrealwriters)
+ return;
+ while (!torture_must_stop())
+ schedule_timeout_uninterruptible(1);
+}
+
+/*
+ * RCU scalability reader kthread. Repeatedly does empty RCU read-side
+ * critical section, minimizing update-side interference. However, the
+ * point of this test is not to evaluate reader scalability, but instead
+ * to serve as a test load for update-side scalability testing.
+ */
+static int
+rcu_scale_reader(void *arg)
+{
+ unsigned long flags;
+ int idx;
+ long me = (long)arg;
+
+ VERBOSE_SCALEOUT_STRING("rcu_scale_reader task started");
+ set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
+ set_user_nice(current, MAX_NICE);
+ atomic_inc(&n_rcu_scale_reader_started);
+
+ do {
+ local_irq_save(flags);
+ idx = cur_ops->readlock();
+ cur_ops->readunlock(idx);
+ local_irq_restore(flags);
+ rcu_scale_wait_shutdown();
+ } while (!torture_must_stop());
+ torture_kthread_stopping("rcu_scale_reader");
+ return 0;
+}
+
+/*
+ * Callback function for asynchronous grace periods from rcu_scale_writer().
+ */
+static void rcu_scale_async_cb(struct rcu_head *rhp)
+{
+ atomic_dec(this_cpu_ptr(&n_async_inflight));
+ kfree(rhp);
+}
+
+/*
+ * RCU scale writer kthread. Repeatedly does a grace period.
+ */
+static int
+rcu_scale_writer(void *arg)
+{
+ int i = 0;
+ int i_max;
+ unsigned long jdone;
+ long me = (long)arg;
+ struct rcu_head *rhp = NULL;
+ bool started = false, done = false, alldone = false;
+ u64 t;
+ DEFINE_TORTURE_RANDOM(tr);
+ u64 *wdp;
+ u64 *wdpp = writer_durations[me];
+
+ VERBOSE_SCALEOUT_STRING("rcu_scale_writer task started");
+ WARN_ON(!wdpp);
+ set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
+ current->flags |= PF_NO_SETAFFINITY;
+ sched_set_fifo_low(current);
+
+ if (holdoff)
+ schedule_timeout_idle(holdoff * HZ);
+
+ /*
+ * Wait until rcu_end_inkernel_boot() is called for normal GP tests
+ * so that RCU is not always expedited for normal GP tests.
+ * The system_state test is approximate, but works well in practice.
+ */
+ while (!gp_exp && system_state != SYSTEM_RUNNING)
+ schedule_timeout_uninterruptible(1);
+
+ t = ktime_get_mono_fast_ns();
+ if (atomic_inc_return(&n_rcu_scale_writer_started) >= nrealwriters) {
+ t_rcu_scale_writer_started = t;
+ if (gp_exp) {
+ b_rcu_gp_test_started =
+ cur_ops->exp_completed() / 2;
+ } else {
+ b_rcu_gp_test_started = cur_ops->get_gp_seq();
+ }
+ }
+
+ jdone = jiffies + minruntime * HZ;
+ do {
+ if (writer_holdoff)
+ udelay(writer_holdoff);
+ if (writer_holdoff_jiffies)
+ schedule_timeout_idle(torture_random(&tr) % writer_holdoff_jiffies + 1);
+ wdp = &wdpp[i];
+ *wdp = ktime_get_mono_fast_ns();
+ if (gp_async) {
+retry:
+ if (!rhp)
+ rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
+ if (rhp && atomic_read(this_cpu_ptr(&n_async_inflight)) < gp_async_max) {
+ atomic_inc(this_cpu_ptr(&n_async_inflight));
+ cur_ops->async(rhp, rcu_scale_async_cb);
+ rhp = NULL;
+ } else if (!kthread_should_stop()) {
+ cur_ops->gp_barrier();
+ goto retry;
+ } else {
+ kfree(rhp); /* Because we are stopping. */
+ }
+ } else if (gp_exp) {
+ cur_ops->exp_sync();
+ } else {
+ cur_ops->sync();
+ }
+ t = ktime_get_mono_fast_ns();
+ *wdp = t - *wdp;
+ i_max = i;
+ if (!started &&
+ atomic_read(&n_rcu_scale_writer_started) >= nrealwriters)
+ started = true;
+ if (!done && i >= MIN_MEAS && time_after(jiffies, jdone)) {
+ done = true;
+ sched_set_normal(current, 0);
+ pr_alert("%s%s rcu_scale_writer %ld has %d measurements\n",
+ scale_type, SCALE_FLAG, me, MIN_MEAS);
+ if (atomic_inc_return(&n_rcu_scale_writer_finished) >=
+ nrealwriters) {
+ schedule_timeout_interruptible(10);
+ rcu_ftrace_dump(DUMP_ALL);
+ SCALEOUT_STRING("Test complete");
+ t_rcu_scale_writer_finished = t;
+ if (gp_exp) {
+ b_rcu_gp_test_finished =
+ cur_ops->exp_completed() / 2;
+ } else {
+ b_rcu_gp_test_finished =
+ cur_ops->get_gp_seq();
+ }
+ if (shutdown) {
+ smp_mb(); /* Assign before wake. */
+ wake_up(&shutdown_wq);
+ }
+ }
+ }
+ if (done && !alldone &&
+ atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters)
+ alldone = true;
+ if (started && !alldone && i < MAX_MEAS - 1)
+ i++;
+ rcu_scale_wait_shutdown();
+ } while (!torture_must_stop());
+ if (gp_async) {
+ cur_ops->gp_barrier();
+ }
+ writer_n_durations[me] = i_max + 1;
+ torture_kthread_stopping("rcu_scale_writer");
+ return 0;
+}
+
+static void
+rcu_scale_print_module_parms(struct rcu_scale_ops *cur_ops, const char *tag)
+{
+ pr_alert("%s" SCALE_FLAG
+ "--- %s: gp_async=%d gp_async_max=%d gp_exp=%d holdoff=%d minruntime=%d nreaders=%d nwriters=%d writer_holdoff=%d writer_holdoff_jiffies=%d verbose=%d shutdown=%d\n",
+ scale_type, tag, gp_async, gp_async_max, gp_exp, holdoff, minruntime, nrealreaders, nrealwriters, writer_holdoff, writer_holdoff_jiffies, verbose, shutdown);
+}
+
+/*
+ * Return the number if non-negative. If -1, the number of CPUs.
+ * If less than -1, that much less than the number of CPUs, but
+ * at least one.
+ */
+static int compute_real(int n)
+{
+ int nr;
+
+ if (n >= 0) {
+ nr = n;
+ } else {
+ nr = num_online_cpus() + 1 + n;
+ if (nr <= 0)
+ nr = 1;
+ }
+ return nr;
+}
+
+/*
+ * kfree_rcu() scalability tests: Start a kfree_rcu() loop on all CPUs for number
+ * of iterations and measure total time and number of GP for all iterations to complete.
+ */
+
+torture_param(int, kfree_nthreads, -1, "Number of threads running loops of kfree_rcu().");
+torture_param(int, kfree_alloc_num, 8000, "Number of allocations and frees done in an iteration.");
+torture_param(int, kfree_loops, 10, "Number of loops doing kfree_alloc_num allocations and frees.");
+torture_param(bool, kfree_rcu_test_double, false, "Do we run a kfree_rcu() double-argument scale test?");
+torture_param(bool, kfree_rcu_test_single, false, "Do we run a kfree_rcu() single-argument scale test?");
+
+static struct task_struct **kfree_reader_tasks;
+static int kfree_nrealthreads;
+static atomic_t n_kfree_scale_thread_started;
+static atomic_t n_kfree_scale_thread_ended;
+static struct task_struct *kthread_tp;
+static u64 kthread_stime;
+
+struct kfree_obj {
+ char kfree_obj[8];
+ struct rcu_head rh;
+};
+
+/* Used if doing RCU-kfree'ing via call_rcu(). */
+static void kfree_call_rcu(struct rcu_head *rh)
+{
+ struct kfree_obj *obj = container_of(rh, struct kfree_obj, rh);
+
+ kfree(obj);
+}
+
+static int
+kfree_scale_thread(void *arg)
+{
+ int i, loop = 0;
+ long me = (long)arg;
+ struct kfree_obj *alloc_ptr;
+ u64 start_time, end_time;
+ long long mem_begin, mem_during = 0;
+ bool kfree_rcu_test_both;
+ DEFINE_TORTURE_RANDOM(tr);
+
+ VERBOSE_SCALEOUT_STRING("kfree_scale_thread task started");
+ set_cpus_allowed_ptr(current, cpumask_of(me % nr_cpu_ids));
+ set_user_nice(current, MAX_NICE);
+ kfree_rcu_test_both = (kfree_rcu_test_single == kfree_rcu_test_double);
+
+ start_time = ktime_get_mono_fast_ns();
+
+ if (atomic_inc_return(&n_kfree_scale_thread_started) >= kfree_nrealthreads) {
+ if (gp_exp)
+ b_rcu_gp_test_started = cur_ops->exp_completed() / 2;
+ else
+ b_rcu_gp_test_started = cur_ops->get_gp_seq();
+ }
+
+ do {
+ if (!mem_during) {
+ mem_during = mem_begin = si_mem_available();
+ } else if (loop % (kfree_loops / 4) == 0) {
+ mem_during = (mem_during + si_mem_available()) / 2;
+ }
+
+ for (i = 0; i < kfree_alloc_num; i++) {
+ alloc_ptr = kmalloc(kfree_mult * sizeof(struct kfree_obj), GFP_KERNEL);
+ if (!alloc_ptr)
+ return -ENOMEM;
+
+ if (kfree_by_call_rcu) {
+ call_rcu(&(alloc_ptr->rh), kfree_call_rcu);
+ continue;
+ }
+
+ // By default kfree_rcu_test_single and kfree_rcu_test_double are
+ // initialized to false. If both have the same value (false or true)
+ // both are randomly tested, otherwise only the one with value true
+ // is tested.
+ if ((kfree_rcu_test_single && !kfree_rcu_test_double) ||
+ (kfree_rcu_test_both && torture_random(&tr) & 0x800))
+ kfree_rcu_mightsleep(alloc_ptr);
+ else
+ kfree_rcu(alloc_ptr, rh);
+ }
+
+ cond_resched();
+ } while (!torture_must_stop() && ++loop < kfree_loops);
+
+ if (atomic_inc_return(&n_kfree_scale_thread_ended) >= kfree_nrealthreads) {
+ end_time = ktime_get_mono_fast_ns();
+
+ if (gp_exp)
+ b_rcu_gp_test_finished = cur_ops->exp_completed() / 2;
+ else
+ b_rcu_gp_test_finished = cur_ops->get_gp_seq();
+
+ pr_alert("Total time taken by all kfree'ers: %llu ns, loops: %d, batches: %ld, memory footprint: %lldMB\n",
+ (unsigned long long)(end_time - start_time), kfree_loops,
+ rcuscale_seq_diff(b_rcu_gp_test_finished, b_rcu_gp_test_started),
+ (mem_begin - mem_during) >> (20 - PAGE_SHIFT));
+
+ if (shutdown) {
+ smp_mb(); /* Assign before wake. */
+ wake_up(&shutdown_wq);
+ }
+ }
+
+ torture_kthread_stopping("kfree_scale_thread");
+ return 0;
+}
+
+static void
+kfree_scale_cleanup(void)
+{
+ int i;
+
+ if (torture_cleanup_begin())
+ return;
+
+ if (kfree_reader_tasks) {
+ for (i = 0; i < kfree_nrealthreads; i++)
+ torture_stop_kthread(kfree_scale_thread,
+ kfree_reader_tasks[i]);
+ kfree(kfree_reader_tasks);
+ }
+
+ torture_cleanup_end();
+}
+
+/*
+ * shutdown kthread. Just waits to be awakened, then shuts down system.
+ */
+static int
+kfree_scale_shutdown(void *arg)
+{
+ wait_event_idle(shutdown_wq,
+ atomic_read(&n_kfree_scale_thread_ended) >= kfree_nrealthreads);
+
+ smp_mb(); /* Wake before output. */
+
+ kfree_scale_cleanup();
+ kernel_power_off();
+ return -EINVAL;
+}
+
+// Used if doing RCU-kfree'ing via call_rcu().
+static unsigned long jiffies_at_lazy_cb;
+static struct rcu_head lazy_test1_rh;
+static int rcu_lazy_test1_cb_called;
+static void call_rcu_lazy_test1(struct rcu_head *rh)
+{
+ jiffies_at_lazy_cb = jiffies;
+ WRITE_ONCE(rcu_lazy_test1_cb_called, 1);
+}
+
+static int __init
+kfree_scale_init(void)
+{
+ int firsterr = 0;
+ long i;
+ unsigned long jif_start;
+ unsigned long orig_jif;
+
+ pr_alert("%s" SCALE_FLAG
+ "--- kfree_rcu_test: kfree_mult=%d kfree_by_call_rcu=%d kfree_nthreads=%d kfree_alloc_num=%d kfree_loops=%d kfree_rcu_test_double=%d kfree_rcu_test_single=%d\n",
+ scale_type, kfree_mult, kfree_by_call_rcu, kfree_nthreads, kfree_alloc_num, kfree_loops, kfree_rcu_test_double, kfree_rcu_test_single);
+
+ // Also, do a quick self-test to ensure laziness is as much as
+ // expected.
+ if (kfree_by_call_rcu && !IS_ENABLED(CONFIG_RCU_LAZY)) {
+ pr_alert("CONFIG_RCU_LAZY is disabled, falling back to kfree_rcu() for delayed RCU kfree'ing\n");
+ kfree_by_call_rcu = 0;
+ }
+
+ if (kfree_by_call_rcu) {
+ /* do a test to check the timeout. */
+ orig_jif = rcu_lazy_get_jiffies_till_flush();
+
+ rcu_lazy_set_jiffies_till_flush(2 * HZ);
+ rcu_barrier();
+
+ jif_start = jiffies;
+ jiffies_at_lazy_cb = 0;
+ call_rcu(&lazy_test1_rh, call_rcu_lazy_test1);
+
+ smp_cond_load_relaxed(&rcu_lazy_test1_cb_called, VAL == 1);
+
+ rcu_lazy_set_jiffies_till_flush(orig_jif);
+
+ if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start < 2 * HZ)) {
+ pr_alert("ERROR: call_rcu() CBs are not being lazy as expected!\n");
+ WARN_ON_ONCE(1);
+ return -1;
+ }
+
+ if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start > 3 * HZ)) {
+ pr_alert("ERROR: call_rcu() CBs are being too lazy!\n");
+ WARN_ON_ONCE(1);
+ return -1;
+ }
+ }
+
+ kfree_nrealthreads = compute_real(kfree_nthreads);
+ /* Start up the kthreads. */
+ if (shutdown) {
+ init_waitqueue_head(&shutdown_wq);
+ firsterr = torture_create_kthread(kfree_scale_shutdown, NULL,
+ shutdown_task);
+ if (torture_init_error(firsterr))
+ goto unwind;
+ schedule_timeout_uninterruptible(1);
+ }
+
+ pr_alert("kfree object size=%zu, kfree_by_call_rcu=%d\n",
+ kfree_mult * sizeof(struct kfree_obj),
+ kfree_by_call_rcu);
+
+ kfree_reader_tasks = kcalloc(kfree_nrealthreads, sizeof(kfree_reader_tasks[0]),
+ GFP_KERNEL);
+ if (kfree_reader_tasks == NULL) {
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
+
+ for (i = 0; i < kfree_nrealthreads; i++) {
+ firsterr = torture_create_kthread(kfree_scale_thread, (void *)i,
+ kfree_reader_tasks[i]);
+ if (torture_init_error(firsterr))
+ goto unwind;
+ }
+
+ while (atomic_read(&n_kfree_scale_thread_started) < kfree_nrealthreads)
+ schedule_timeout_uninterruptible(1);
+
+ torture_init_end();
+ return 0;
+
+unwind:
+ torture_init_end();
+ kfree_scale_cleanup();
+ return firsterr;
+}
+
+static void
+rcu_scale_cleanup(void)
+{
+ int i;
+ int j;
+ int ngps = 0;
+ u64 *wdp;
+ u64 *wdpp;
+
+ /*
+ * Would like warning at start, but everything is expedited
+ * during the mid-boot phase, so have to wait till the end.
+ */
+ if (rcu_gp_is_expedited() && !rcu_gp_is_normal() && !gp_exp)
+ SCALEOUT_ERRSTRING("All grace periods expedited, no normal ones to measure!");
+ if (rcu_gp_is_normal() && gp_exp)
+ SCALEOUT_ERRSTRING("All grace periods normal, no expedited ones to measure!");
+ if (gp_exp && gp_async)
+ SCALEOUT_ERRSTRING("No expedited async GPs, so went with async!");
+
+ // If built-in, just report all of the GP kthread's CPU time.
+ if (IS_BUILTIN(CONFIG_RCU_SCALE_TEST) && !kthread_tp && cur_ops->rso_gp_kthread)
+ kthread_tp = cur_ops->rso_gp_kthread();
+ if (kthread_tp) {
+ u32 ns;
+ u64 us;
+
+ kthread_stime = kthread_tp->stime - kthread_stime;
+ us = div_u64_rem(kthread_stime, 1000, &ns);
+ pr_info("rcu_scale: Grace-period kthread CPU time: %llu.%03u us\n", us, ns);
+ show_rcu_gp_kthreads();
+ }
+ if (kfree_rcu_test) {
+ kfree_scale_cleanup();
+ return;
+ }
+
+ if (torture_cleanup_begin())
+ return;
+ if (!cur_ops) {
+ torture_cleanup_end();
+ return;
+ }
+
+ if (reader_tasks) {
+ for (i = 0; i < nrealreaders; i++)
+ torture_stop_kthread(rcu_scale_reader,
+ reader_tasks[i]);
+ kfree(reader_tasks);
+ }
+
+ if (writer_tasks) {
+ for (i = 0; i < nrealwriters; i++) {
+ torture_stop_kthread(rcu_scale_writer,
+ writer_tasks[i]);
+ if (!writer_n_durations)
+ continue;
+ j = writer_n_durations[i];
+ pr_alert("%s%s writer %d gps: %d\n",
+ scale_type, SCALE_FLAG, i, j);
+ ngps += j;
+ }
+ pr_alert("%s%s start: %llu end: %llu duration: %llu gps: %d batches: %ld\n",
+ scale_type, SCALE_FLAG,
+ t_rcu_scale_writer_started, t_rcu_scale_writer_finished,
+ t_rcu_scale_writer_finished -
+ t_rcu_scale_writer_started,
+ ngps,
+ rcuscale_seq_diff(b_rcu_gp_test_finished,
+ b_rcu_gp_test_started));
+ for (i = 0; i < nrealwriters; i++) {
+ if (!writer_durations)
+ break;
+ if (!writer_n_durations)
+ continue;
+ wdpp = writer_durations[i];
+ if (!wdpp)
+ continue;
+ for (j = 0; j < writer_n_durations[i]; j++) {
+ wdp = &wdpp[j];
+ pr_alert("%s%s %4d writer-duration: %5d %llu\n",
+ scale_type, SCALE_FLAG,
+ i, j, *wdp);
+ if (j % 100 == 0)
+ schedule_timeout_uninterruptible(1);
+ }
+ kfree(writer_durations[i]);
+ }
+ kfree(writer_tasks);
+ kfree(writer_durations);
+ kfree(writer_n_durations);
+ }
+
+ /* Do torture-type-specific cleanup operations. */
+ if (cur_ops->cleanup != NULL)
+ cur_ops->cleanup();
+
+ torture_cleanup_end();
+}
+
+/*
+ * RCU scalability shutdown kthread. Just waits to be awakened, then shuts
+ * down system.
+ */
+static int
+rcu_scale_shutdown(void *arg)
+{
+ wait_event_idle(shutdown_wq, atomic_read(&n_rcu_scale_writer_finished) >= nrealwriters);
+ smp_mb(); /* Wake before output. */
+ rcu_scale_cleanup();
+ kernel_power_off();
+ return -EINVAL;
+}
+
+static int __init
+rcu_scale_init(void)
+{
+ long i;
+ int firsterr = 0;
+ static struct rcu_scale_ops *scale_ops[] = {
+ &rcu_ops, &srcu_ops, &srcud_ops, TASKS_OPS TASKS_RUDE_OPS TASKS_TRACING_OPS
+ };
+
+ if (!torture_init_begin(scale_type, verbose))
+ return -EBUSY;
+
+ /* Process args and announce that the scalability'er is on the job. */
+ for (i = 0; i < ARRAY_SIZE(scale_ops); i++) {
+ cur_ops = scale_ops[i];
+ if (strcmp(scale_type, cur_ops->name) == 0)
+ break;
+ }
+ if (i == ARRAY_SIZE(scale_ops)) {
+ pr_alert("rcu-scale: invalid scale type: \"%s\"\n", scale_type);
+ pr_alert("rcu-scale types:");
+ for (i = 0; i < ARRAY_SIZE(scale_ops); i++)
+ pr_cont(" %s", scale_ops[i]->name);
+ pr_cont("\n");
+ firsterr = -EINVAL;
+ cur_ops = NULL;
+ goto unwind;
+ }
+ if (cur_ops->init)
+ cur_ops->init();
+
+ if (cur_ops->rso_gp_kthread) {
+ kthread_tp = cur_ops->rso_gp_kthread();
+ if (kthread_tp)
+ kthread_stime = kthread_tp->stime;
+ }
+ if (kfree_rcu_test)
+ return kfree_scale_init();
+
+ nrealwriters = compute_real(nwriters);
+ nrealreaders = compute_real(nreaders);
+ atomic_set(&n_rcu_scale_reader_started, 0);
+ atomic_set(&n_rcu_scale_writer_started, 0);
+ atomic_set(&n_rcu_scale_writer_finished, 0);
+ rcu_scale_print_module_parms(cur_ops, "Start of test");
+
+ /* Start up the kthreads. */
+
+ if (shutdown) {
+ init_waitqueue_head(&shutdown_wq);
+ firsterr = torture_create_kthread(rcu_scale_shutdown, NULL,
+ shutdown_task);
+ if (torture_init_error(firsterr))
+ goto unwind;
+ schedule_timeout_uninterruptible(1);
+ }
+ reader_tasks = kcalloc(nrealreaders, sizeof(reader_tasks[0]),
+ GFP_KERNEL);
+ if (reader_tasks == NULL) {
+ SCALEOUT_ERRSTRING("out of memory");
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
+ for (i = 0; i < nrealreaders; i++) {
+ firsterr = torture_create_kthread(rcu_scale_reader, (void *)i,
+ reader_tasks[i]);
+ if (torture_init_error(firsterr))
+ goto unwind;
+ }
+ while (atomic_read(&n_rcu_scale_reader_started) < nrealreaders)
+ schedule_timeout_uninterruptible(1);
+ writer_tasks = kcalloc(nrealwriters, sizeof(reader_tasks[0]),
+ GFP_KERNEL);
+ writer_durations = kcalloc(nrealwriters, sizeof(*writer_durations),
+ GFP_KERNEL);
+ writer_n_durations =
+ kcalloc(nrealwriters, sizeof(*writer_n_durations),
+ GFP_KERNEL);
+ if (!writer_tasks || !writer_durations || !writer_n_durations) {
+ SCALEOUT_ERRSTRING("out of memory");
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
+ for (i = 0; i < nrealwriters; i++) {
+ writer_durations[i] =
+ kcalloc(MAX_MEAS, sizeof(*writer_durations[i]),
+ GFP_KERNEL);
+ if (!writer_durations[i]) {
+ firsterr = -ENOMEM;
+ goto unwind;
+ }
+ firsterr = torture_create_kthread(rcu_scale_writer, (void *)i,
+ writer_tasks[i]);
+ if (torture_init_error(firsterr))
+ goto unwind;
+ }
+ torture_init_end();
+ return 0;
+
+unwind:
+ torture_init_end();
+ rcu_scale_cleanup();
+ if (shutdown) {
+ WARN_ON(!IS_MODULE(CONFIG_RCU_SCALE_TEST));
+ kernel_power_off();
+ }
+ return firsterr;
+}
+
+module_init(rcu_scale_init);
+module_exit(rcu_scale_cleanup);