scftorture: Add smp_call_function() torture test
This commit adds an smp_call_function() torture test that repeatedly invokes this function and complains if things go badly awry. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
This commit is contained in:
Paul E. McKenney
parent
9123e3a74e
commit
e9d338a0b1
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@ -4637,6 +4637,98 @@
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Format: integer between 0 and 10
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Default is 0.
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scftorture.holdoff= [KNL]
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Number of seconds to hold off before starting
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test. Defaults to zero for module insertion and
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to 10 seconds for built-in smp_call_function()
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tests.
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scftorture.longwait= [KNL]
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Request ridiculously long waits randomly selected
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up to the chosen limit in seconds. Zero (the
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default) disables this feature. Please note
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that requesting even small non-zero numbers of
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seconds can result in RCU CPU stall warnings,
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softlockup complaints, and so on.
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scftorture.nthreads= [KNL]
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Number of kthreads to spawn to invoke the
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smp_call_function() family of functions.
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The default of -1 specifies a number of kthreads
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equal to the number of CPUs.
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scftorture.onoff_holdoff= [KNL]
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Number seconds to wait after the start of the
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test before initiating CPU-hotplug operations.
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scftorture.onoff_interval= [KNL]
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Number seconds to wait between successive
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CPU-hotplug operations. Specifying zero (which
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is the default) disables CPU-hotplug operations.
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scftorture.shutdown_secs= [KNL]
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The number of seconds following the start of the
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test after which to shut down the system. The
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default of zero avoids shutting down the system.
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Non-zero values are useful for automated tests.
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scftorture.stat_interval= [KNL]
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The number of seconds between outputting the
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current test statistics to the console. A value
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of zero disables statistics output.
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scftorture.stutter_cpus= [KNL]
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The number of jiffies to wait between each change
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to the set of CPUs under test.
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scftorture.use_cpus_read_lock= [KNL]
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Use use_cpus_read_lock() instead of the default
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preempt_disable() to disable CPU hotplug
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while invoking one of the smp_call_function*()
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functions.
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scftorture.verbose= [KNL]
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Enable additional printk() statements.
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scftorture.weight_single= [KNL]
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The probability weighting to use for the
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smp_call_function_single() function with a zero
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"wait" parameter. A value of -1 selects the
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default if all other weights are -1. However,
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if at least one weight has some other value, a
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value of -1 will instead select a weight of zero.
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scftorture.weight_single_wait= [KNL]
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The probability weighting to use for the
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smp_call_function_single() function with a
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non-zero "wait" parameter. See weight_single.
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scftorture.weight_many= [KNL]
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The probability weighting to use for the
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smp_call_function_many() function with a zero
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"wait" parameter. See weight_single.
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Note well that setting a high probability for
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this weighting can place serious IPI load
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on the system.
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scftorture.weight_many_wait= [KNL]
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The probability weighting to use for the
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smp_call_function_many() function with a
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non-zero "wait" parameter. See weight_single
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and weight_many.
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scftorture.weight_all= [KNL]
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The probability weighting to use for the
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smp_call_function_all() function with a zero
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"wait" parameter. See weight_single and
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weight_many.
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scftorture.weight_all_wait= [KNL]
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The probability weighting to use for the
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smp_call_function_all() function with a
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non-zero "wait" parameter. See weight_single
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and weight_many.
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skew_tick= [KNL] Offset the periodic timer tick per cpu to mitigate
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xtime_lock contention on larger systems, and/or RCU lock
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contention on all systems with CONFIG_MAXSMP set.
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@ -133,6 +133,8 @@ KASAN_SANITIZE_stackleak.o := n
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KCSAN_SANITIZE_stackleak.o := n
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KCOV_INSTRUMENT_stackleak.o := n
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obj-$(CONFIG_SCF_TORTURE_TEST) += scftorture.o
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$(obj)/configs.o: $(obj)/config_data.gz
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targets += config_data.gz
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@ -0,0 +1,350 @@
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// SPDX-License-Identifier: GPL-2.0+
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//
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// Torture test for smp_call_function() and friends.
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//
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// Copyright (C) Facebook, 2020.
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//
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// Author: Paul E. McKenney <paulmck@kernel.org>
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#define pr_fmt(fmt) fmt
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#include <linux/atomic.h>
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#include <linux/bitops.h>
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#include <linux/completion.h>
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#include <linux/cpu.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kthread.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/notifier.h>
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#include <linux/percpu.h>
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#include <linux/rcupdate.h>
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#include <linux/rcupdate_trace.h>
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#include <linux/reboot.h>
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#include <linux/sched.h>
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#include <linux/spinlock.h>
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#include <linux/smp.h>
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#include <linux/stat.h>
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#include <linux/srcu.h>
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#include <linux/slab.h>
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#include <linux/torture.h>
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#include <linux/types.h>
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#define SCFTORT_STRING "scftorture"
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#define SCFTORT_FLAG SCFTORT_STRING ": "
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#define SCFTORTOUT(s, x...) \
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pr_alert(SCFTORT_FLAG s, ## x)
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#define VERBOSE_SCFTORTOUT(s, x...) \
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do { if (verbose) pr_alert(SCFTORT_FLAG s, ## x); } while (0)
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#define VERBOSE_SCFTORTOUT_ERRSTRING(s, x...) \
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do { if (verbose) pr_alert(SCFTORT_FLAG "!!! " s, ## x); } while (0)
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Paul E. McKenney <paulmck@kernel.org>");
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// Wait until there are multiple CPUs before starting test.
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torture_param(int, holdoff, IS_BUILTIN(CONFIG_SCF_TORTURE_TEST) ? 10 : 0,
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"Holdoff time before test start (s)");
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torture_param(int, longwait, 0, "Include ridiculously long waits? (seconds)");
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torture_param(int, nthreads, -1, "# threads, defaults to -1 for all CPUs.");
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torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
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torture_param(int, onoff_interval, 0, "Time between CPU hotplugs (s), 0=disable");
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torture_param(int, shutdown_secs, 0, "Shutdown time (ms), <= zero to disable.");
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torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s.");
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torture_param(int, stutter_cpus, 5, "Number of jiffies to change CPUs under test, 0=disable");
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torture_param(bool, use_cpus_read_lock, 0, "Use cpus_read_lock() to exclude CPU hotplug.");
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torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
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torture_param(int, weight_single, -1, "Testing weight for single-CPU no-wait operations.");
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torture_param(int, weight_single_wait, -1, "Testing weight for single-CPU operations.");
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torture_param(int, weight_mult, -1, "Testing weight for multi-CPU no-wait operations.");
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torture_param(int, weight_mult_wait, -1, "Testing weight for multi-CPU operations.");
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torture_param(int, weight_all, -1, "Testing weight for all-CPU no-wait operations.");
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torture_param(int, weight_all_wait, -1, "Testing weight for all-CPU operations.");
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char *torture_type = "";
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#ifdef MODULE
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# define SCFTORT_SHUTDOWN 0
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#else
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# define SCFTORT_SHUTDOWN 1
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#endif
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torture_param(bool, shutdown, SCFTORT_SHUTDOWN, "Shutdown at end of torture test.");
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struct scf_statistics {
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struct task_struct *task;
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int cpu;
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long long n_single;
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long long n_single_wait;
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long long n_multi;
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long long n_multi_wait;
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long long n_all;
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long long n_all_wait;
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};
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static struct scf_statistics *scf_stats_p;
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static struct task_struct *scf_torture_stats_task;
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static DEFINE_PER_CPU(long long, scf_invoked_count);
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// Use to wait for all threads to start.
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static atomic_t n_started;
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static atomic_t n_errs;
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static bool scfdone;
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DEFINE_TORTURE_RANDOM_PERCPU(scf_torture_rand);
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// Print torture statistics. Caller must ensure serialization.
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static void scf_torture_stats_print(void)
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{
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int cpu;
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long long invoked_count = 0;
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bool isdone = READ_ONCE(scfdone);
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for_each_possible_cpu(cpu)
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invoked_count += data_race(per_cpu(scf_invoked_count, cpu));
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pr_alert("%s scf_invoked_count %s: %lld ",
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SCFTORT_FLAG, isdone ? "VER" : "ver", invoked_count);
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torture_onoff_stats();
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pr_cont("\n");
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}
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// Periodically prints torture statistics, if periodic statistics printing
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// was specified via the stat_interval module parameter.
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static int
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scf_torture_stats(void *arg)
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{
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VERBOSE_TOROUT_STRING("scf_torture_stats task started");
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do {
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schedule_timeout_interruptible(stat_interval * HZ);
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scf_torture_stats_print();
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torture_shutdown_absorb("scf_torture_stats");
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} while (!torture_must_stop());
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torture_kthread_stopping("scf_torture_stats");
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return 0;
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}
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// Update statistics and occasionally burn up mass quantities of CPU time,
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// if told to do so via scftorture.longwait. Otherwise, occasionally burn
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// a little bit.
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static void scf_handler(void *unused)
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{
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int i;
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int j;
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unsigned long r = torture_random(this_cpu_ptr(&scf_torture_rand));
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this_cpu_inc(scf_invoked_count);
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if (longwait <= 0) {
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if (!(r & 0xffc0))
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udelay(r & 0x3f);
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return;
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}
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if (r & 0xfff)
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return;
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r = (r >> 12);
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if (longwait <= 0) {
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udelay((r & 0xff) + 1);
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return;
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}
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r = r % longwait + 1;
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for (i = 0; i < r; i++) {
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for (j = 0; j < 1000; j++) {
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udelay(1000);
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cpu_relax();
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}
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}
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}
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// Randomly do an smp_call_function*() invocation.
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static void scftorture_invoke_one(struct scf_statistics *scfp,struct torture_random_state *trsp)
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{
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if (use_cpus_read_lock)
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cpus_read_lock();
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else
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preempt_disable();
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scfp->n_all++;
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smp_call_function(scf_handler, NULL, 0);
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if (use_cpus_read_lock)
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cpus_read_unlock();
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else
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preempt_enable();
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if (!(torture_random(trsp) & 0xfff))
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schedule_timeout_uninterruptible(1);
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}
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// SCF test kthread. Repeatedly does calls to members of the
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// smp_call_function() family of functions.
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static int scftorture_invoker(void *arg)
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{
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DEFINE_TORTURE_RANDOM(rand);
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struct scf_statistics *scfp = (struct scf_statistics *)arg;
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VERBOSE_SCFTORTOUT("scftorture_invoker %d: task started", scfp->cpu);
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set_cpus_allowed_ptr(current, cpumask_of(scfp->cpu % nr_cpu_ids));
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set_user_nice(current, MAX_NICE);
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if (holdoff)
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schedule_timeout_interruptible(holdoff * HZ);
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VERBOSE_SCFTORTOUT("scftorture_invoker %d: Waiting for all SCF torturers from cpu %d", scfp->cpu, smp_processor_id());
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// Make sure that the CPU is affinitized appropriately during testing.
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WARN_ON_ONCE(smp_processor_id() != scfp->cpu);
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if (!atomic_dec_return(&n_started))
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while (atomic_read_acquire(&n_started)) {
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if (torture_must_stop()) {
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VERBOSE_SCFTORTOUT("scftorture_invoker %d ended before starting", scfp->cpu);
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goto end;
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}
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schedule_timeout_uninterruptible(1);
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}
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VERBOSE_SCFTORTOUT("scftorture_invoker %d started", scfp->cpu);
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do {
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scftorture_invoke_one(scfp, &rand);
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} while (!torture_must_stop());
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VERBOSE_SCFTORTOUT("scftorture_invoker %d ended", scfp->cpu);
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end:
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torture_kthread_stopping("scftorture_invoker");
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return 0;
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}
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static void
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scftorture_print_module_parms(const char *tag)
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{
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pr_alert(SCFTORT_FLAG
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"--- %s: verbose=%d holdoff=%d longwait=%d nthreads=%d onoff_holdoff=%d onoff_interval=%d shutdown_secs=%d stat_interval=%d stutter_cpus=%d use_cpus_read_lock=%d, weight_single=%d, weight_single_wait=%d, weight_mult=%d, weight_mult_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag,
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verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter_cpus, use_cpus_read_lock, weight_single, weight_single_wait, weight_mult, weight_mult_wait, weight_all, weight_all_wait);
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}
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static void scf_cleanup_handler(void *unused)
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{
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}
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static void scf_torture_cleanup(void)
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{
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int i;
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if (torture_cleanup_begin())
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return;
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WRITE_ONCE(scfdone, true);
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if (nthreads)
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for (i = 0; i < nthreads; i++)
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torture_stop_kthread("scftorture_invoker", scf_stats_p[i].task);
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else
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goto end;
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kfree(scf_stats_p);
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scf_stats_p = NULL;
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smp_call_function(scf_cleanup_handler, NULL, 0);
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torture_stop_kthread(scf_torture_stats, scf_torture_stats_task);
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scf_torture_stats_print(); // -After- the stats thread is stopped!
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if (atomic_read(&n_errs))
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scftorture_print_module_parms("End of test: FAILURE");
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else if (torture_onoff_failures())
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scftorture_print_module_parms("End of test: LOCK_HOTPLUG");
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else
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scftorture_print_module_parms("End of test: SUCCESS");
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end:
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torture_cleanup_end();
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}
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static int __init scf_torture_init(void)
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{
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long i;
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int firsterr = 0;
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if (!torture_init_begin(SCFTORT_STRING, verbose))
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return -EBUSY;
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scftorture_print_module_parms("Start of test");
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if (weight_single == -1 && weight_single_wait == -1 &&
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weight_mult == -1 && weight_mult_wait == -1 &&
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weight_all == -1 && weight_all_wait == -1) {
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weight_single = 1;
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weight_single_wait = 1;
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weight_mult = 1;
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weight_mult_wait = 1;
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weight_all = 1;
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weight_all_wait = 1;
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} else {
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if (weight_single == -1)
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weight_single = 0;
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if (weight_single_wait == -1)
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weight_single_wait = 0;
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if (weight_mult == -1)
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weight_mult = 0;
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if (weight_mult_wait == -1)
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weight_mult_wait = 0;
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if (weight_all == -1)
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weight_all = 0;
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if (weight_all_wait == -1)
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weight_all_wait = 0;
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}
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if (weight_single == 0 && weight_single_wait == 0 &&
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weight_mult == 0 && weight_mult_wait == 0 &&
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weight_all == 0 && weight_all_wait == 0) {
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firsterr = -EINVAL;
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goto unwind;
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}
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if (onoff_interval > 0) {
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firsterr = torture_onoff_init(onoff_holdoff * HZ, onoff_interval, NULL);
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if (firsterr)
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goto unwind;
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}
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if (shutdown_secs > 0) {
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firsterr = torture_shutdown_init(shutdown_secs, scf_torture_cleanup);
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if (firsterr)
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goto unwind;
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}
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// Worker tasks invoking smp_call_function().
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if (nthreads < 0)
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nthreads = num_online_cpus();
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scf_stats_p = kcalloc(nthreads, sizeof(scf_stats_p[0]), GFP_KERNEL);
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if (!scf_stats_p) {
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VERBOSE_SCFTORTOUT_ERRSTRING("out of memory");
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firsterr = -ENOMEM;
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goto unwind;
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}
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VERBOSE_SCFTORTOUT("Starting %d smp_call_function() threads\n", nthreads);
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atomic_set(&n_started, nthreads);
|
||||
for (i = 0; i < nthreads; i++) {
|
||||
scf_stats_p[i].cpu = i;
|
||||
firsterr = torture_create_kthread(scftorture_invoker, (void *)&scf_stats_p[i],
|
||||
scf_stats_p[i].task);
|
||||
if (firsterr)
|
||||
goto unwind;
|
||||
}
|
||||
if (stat_interval > 0) {
|
||||
firsterr = torture_create_kthread(scf_torture_stats, NULL, scf_torture_stats_task);
|
||||
if (firsterr)
|
||||
goto unwind;
|
||||
}
|
||||
|
||||
torture_init_end();
|
||||
return 0;
|
||||
|
||||
unwind:
|
||||
torture_init_end();
|
||||
scf_torture_cleanup();
|
||||
return firsterr;
|
||||
}
|
||||
|
||||
module_init(scf_torture_init);
|
||||
module_exit(scf_torture_cleanup);
|
||||
|
|
@ -1367,6 +1367,16 @@ config WW_MUTEX_SELFTEST
|
|||
Say M if you want these self tests to build as a module.
|
||||
Say N if you are unsure.
|
||||
|
||||
config SCF_TORTURE_TEST
|
||||
tristate "torture tests for smp_call_function*()"
|
||||
depends on DEBUG_KERNEL
|
||||
select TORTURE_TEST
|
||||
help
|
||||
This option provides a kernel module that runs torture tests
|
||||
on the smp_call_function() family of primitives. The kernel
|
||||
module may be built after the fact on the running kernel to
|
||||
be tested, if desired.
|
||||
|
||||
endmenu # lock debugging
|
||||
|
||||
config TRACE_IRQFLAGS
|
||||
|
|
|
|||
Loading…
Reference in New Issue