From 73e3412424832f519004dd2176226982be35d34e Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 27 Jul 2023 20:04:06 -0700 Subject: locktorture: Add readers_bind and writers_bind module parameters This commit adds readers_bind and writers_bind module parameters to locktorture in order to skew tests across socket boundaries. This skewing is intended to provide additional variable-latency stress on the primitive under test. Signed-off-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker --- kernel/locking/locktorture.c | 64 ++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 62 insertions(+), 2 deletions(-) (limited to 'kernel/locking') diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index 270c7f80ce84..441866259278 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -56,6 +56,55 @@ module_param(torture_type, charp, 0444); MODULE_PARM_DESC(torture_type, "Type of lock to torture (spin_lock, spin_lock_irq, mutex_lock, ...)"); +static cpumask_var_t readers_bind; // Bind the readers to the specified set of CPUs. +static cpumask_var_t writers_bind; // Bind the writers to the specified set of CPUs. + +// Parse a cpumask kernel parameter. If there are more users later on, +// this might need to got to a more central location. +static int param_set_cpumask(const char *val, const struct kernel_param *kp) +{ + cpumask_var_t *cm_bind = kp->arg; + int ret; + char *s; + + if (!alloc_cpumask_var(cm_bind, GFP_KERNEL)) { + s = "Out of memory"; + ret = -ENOMEM; + goto out_err; + } + ret = cpulist_parse(val, *cm_bind); + if (!ret) + return ret; + s = "Bad CPU range"; +out_err: + pr_warn("%s: %s, all CPUs set\n", kp->name, s); + cpumask_setall(*cm_bind); + return ret; +} + +// Output a cpumask kernel parameter. +static int param_get_cpumask(char *buffer, const struct kernel_param *kp) +{ + cpumask_var_t *cm_bind = kp->arg; + + return sprintf(buffer, "%*pbl", cpumask_pr_args(*cm_bind)); +} + +static bool cpumask_nonempty(cpumask_var_t mask) +{ + return cpumask_available(mask) && !cpumask_empty(mask); +} + +static const struct kernel_param_ops lt_bind_ops = { + .set = param_set_cpumask, + .get = param_get_cpumask, +}; + +module_param_cb(readers_bind, <_bind_ops, &readers_bind, 0644); +module_param_cb(writers_bind, <_bind_ops, &writers_bind, 0644); + +long torture_sched_setaffinity(pid_t pid, const struct cpumask *in_mask); + static struct task_struct *stats_task; static struct task_struct **writer_tasks; static struct task_struct **reader_tasks; @@ -986,16 +1035,23 @@ static int lock_torture_stats(void *arg) return 0; } + static inline void lock_torture_print_module_parms(struct lock_torture_ops *cur_ops, const char *tag) { + static cpumask_t cpumask_all; + cpumask_t *rcmp = cpumask_nonempty(readers_bind) ? readers_bind : &cpumask_all; + cpumask_t *wcmp = cpumask_nonempty(writers_bind) ? writers_bind : &cpumask_all; + + cpumask_setall(&cpumask_all); pr_alert("%s" TORTURE_FLAG - "--- %s%s: nwriters_stress=%d nreaders_stress=%d nested_locks=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d\n", + "--- %s%s: nwriters_stress=%d nreaders_stress=%d nested_locks=%d stat_interval=%d verbose=%d shuffle_interval=%d stutter=%d shutdown_secs=%d onoff_interval=%d onoff_holdoff=%d readers_bind=%*pbl writers_bind=%*pbl\n", torture_type, tag, cxt.debug_lock ? " [debug]": "", cxt.nrealwriters_stress, cxt.nrealreaders_stress, nested_locks, stat_interval, verbose, shuffle_interval, - stutter, shutdown_secs, onoff_interval, onoff_holdoff); + stutter, shutdown_secs, onoff_interval, onoff_holdoff, + cpumask_pr_args(rcmp), cpumask_pr_args(wcmp)); } static void lock_torture_cleanup(void) @@ -1250,6 +1306,8 @@ static int __init lock_torture_init(void) writer_fifo ? sched_set_fifo : NULL); if (torture_init_error(firsterr)) goto unwind; + if (cpumask_nonempty(writers_bind)) + torture_sched_setaffinity(writer_tasks[i]->pid, writers_bind); create_reader: if (cxt.cur_ops->readlock == NULL || (j >= cxt.nrealreaders_stress)) @@ -1259,6 +1317,8 @@ static int __init lock_torture_init(void) reader_tasks[j]); if (torture_init_error(firsterr)) goto unwind; + if (cpumask_nonempty(readers_bind)) + torture_sched_setaffinity(reader_tasks[j]->pid, readers_bind); } if (stat_interval > 0) { firsterr = torture_create_kthread(lock_torture_stats, NULL, -- cgit v1.2.3-58-ga151