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Diffstat (limited to '')
| -rw-r--r-- | kernel/rcu/rcuscale.c | 1058 |
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); |