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![Paul E. McKenney](/assets/img/avatar_default.png)
The TREE01 rcutorture scenario intentionally creates confusion as to the number of available CPUs by specifying the "maxcpus=8 nr_cpus=43" kernel boot parameters. This can disable rcutorture's load shedding, which currently uses num_online_cpus(), which would count the extra 35 CPUs. However, the rcutorture guest OS will be provisioned with only 8 CPUs, which means that rcutorture will present full load even when all but one of the original 8 CPUs are offline. This can result in spurious errors due to extreme overloading of that single remaining CPU. This commit therefore keeps a separate set of books on the number of usable online CPUs, so that torture_num_online_cpus() is used for load shedding instead of num_online_cpus(). Note that initial sizing must use num_online_cpus() because torture_num_online_cpus() will return NR_CPUS until shortly after torture_onoff_init() is invoked. Reported-by: Frederic Weisbecker <frederic@kernel.org> [ paulmck: Apply feedback from kernel test robot. ] Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
123 lines
4.2 KiB
C
123 lines
4.2 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Common functions for in-kernel torture tests.
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*
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* Copyright IBM Corporation, 2014
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*
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* Author: Paul E. McKenney <paulmck@linux.ibm.com>
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*/
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#ifndef __LINUX_TORTURE_H
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#define __LINUX_TORTURE_H
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#include <linux/types.h>
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#include <linux/cache.h>
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#include <linux/spinlock.h>
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#include <linux/threads.h>
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#include <linux/cpumask.h>
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#include <linux/seqlock.h>
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#include <linux/lockdep.h>
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#include <linux/completion.h>
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#include <linux/debugobjects.h>
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#include <linux/bug.h>
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#include <linux/compiler.h>
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/* Definitions for a non-string torture-test module parameter. */
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#define torture_param(type, name, init, msg) \
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static type name = init; \
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module_param(name, type, 0444); \
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MODULE_PARM_DESC(name, msg);
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#define TORTURE_FLAG "-torture:"
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#define TOROUT_STRING(s) \
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pr_alert("%s" TORTURE_FLAG " %s\n", torture_type, s)
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#define VERBOSE_TOROUT_STRING(s) \
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do { \
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if (verbose) { \
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verbose_torout_sleep(); \
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pr_alert("%s" TORTURE_FLAG " %s\n", torture_type, s); \
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} \
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} while (0)
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#define VERBOSE_TOROUT_ERRSTRING(s) \
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do { \
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if (verbose) { \
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verbose_torout_sleep(); \
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pr_alert("%s" TORTURE_FLAG "!!! %s\n", torture_type, s); \
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} \
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} while (0)
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void verbose_torout_sleep(void);
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/* Definitions for online/offline exerciser. */
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#ifdef CONFIG_HOTPLUG_CPU
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int torture_num_online_cpus(void);
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#else /* #ifdef CONFIG_HOTPLUG_CPU */
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static inline int torture_num_online_cpus(void) { return 1; }
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#endif /* #else #ifdef CONFIG_HOTPLUG_CPU */
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typedef void torture_ofl_func(void);
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bool torture_offline(int cpu, long *n_onl_attempts, long *n_onl_successes,
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unsigned long *sum_offl, int *min_onl, int *max_onl);
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bool torture_online(int cpu, long *n_onl_attempts, long *n_onl_successes,
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unsigned long *sum_onl, int *min_onl, int *max_onl);
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int torture_onoff_init(long ooholdoff, long oointerval, torture_ofl_func *f);
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void torture_onoff_stats(void);
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bool torture_onoff_failures(void);
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/* Low-rider random number generator. */
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struct torture_random_state {
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unsigned long trs_state;
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long trs_count;
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};
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#define DEFINE_TORTURE_RANDOM(name) struct torture_random_state name = { 0, 0 }
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#define DEFINE_TORTURE_RANDOM_PERCPU(name) \
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DEFINE_PER_CPU(struct torture_random_state, name)
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unsigned long torture_random(struct torture_random_state *trsp);
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static inline void torture_random_init(struct torture_random_state *trsp)
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{
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trsp->trs_state = 0;
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trsp->trs_count = 0;
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}
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/* Definitions for high-resolution-timer sleeps. */
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int torture_hrtimeout_ns(ktime_t baset_ns, u32 fuzzt_ns, struct torture_random_state *trsp);
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int torture_hrtimeout_us(u32 baset_us, u32 fuzzt_ns, struct torture_random_state *trsp);
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int torture_hrtimeout_ms(u32 baset_ms, u32 fuzzt_us, struct torture_random_state *trsp);
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int torture_hrtimeout_jiffies(u32 baset_j, struct torture_random_state *trsp);
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int torture_hrtimeout_s(u32 baset_s, u32 fuzzt_ms, struct torture_random_state *trsp);
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/* Task shuffler, which causes CPUs to occasionally go idle. */
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void torture_shuffle_task_register(struct task_struct *tp);
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int torture_shuffle_init(long shuffint);
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/* Test auto-shutdown handling. */
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void torture_shutdown_absorb(const char *title);
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int torture_shutdown_init(int ssecs, void (*cleanup)(void));
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/* Task stuttering, which forces load/no-load transitions. */
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bool stutter_wait(const char *title);
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int torture_stutter_init(int s, int sgap);
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/* Initialization and cleanup. */
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bool torture_init_begin(char *ttype, int v);
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void torture_init_end(void);
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bool torture_cleanup_begin(void);
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void torture_cleanup_end(void);
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bool torture_must_stop(void);
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bool torture_must_stop_irq(void);
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void torture_kthread_stopping(char *title);
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int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
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char *f, struct task_struct **tp);
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void _torture_stop_kthread(char *m, struct task_struct **tp);
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#define torture_create_kthread(n, arg, tp) \
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_torture_create_kthread(n, (arg), #n, "Creating " #n " task", \
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"Failed to create " #n, &(tp))
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#define torture_stop_kthread(n, tp) \
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_torture_stop_kthread("Stopping " #n " task", &(tp))
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#ifdef CONFIG_PREEMPTION
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#define torture_preempt_schedule() preempt_schedule()
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#else
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#define torture_preempt_schedule() do { } while (0)
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#endif
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#endif /* __LINUX_TORTURE_H */
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