Skip to content

Commit

Permalink
scftorture: Add an alternative IPI vector
Browse files Browse the repository at this point in the history 
The scftorture tests currently use only smp_call_function() and
friends, which means that these tests cannot locate bugs caused by
interactions between different IPI vectors.  This commit therefore adds
the rescheduling IPI to the mix.

Note that this commit permits resched_cpus() only when scftorture is
built in.  This is a workaround.  Longer term, this will use real wakeups
rather than resched_cpu().

Signed-off-by: Paul E. McKenney <[email protected]>
  • Loading branch information
@paulmckrcu
paulmckrcu committed Nov 7, 2020
1 parent fda5ba9 commit 1ac78b4
Showing 1 changed file with 32 additions and 9 deletions.
41 changes: 32 additions & 9 deletions kernel/scftorture.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -62,6 +62,7 @@ torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s
torture_param(int, stutter_cpus, 5, "Number of jiffies to change CPUs under test, 0=disable");
torture_param(bool, use_cpus_read_lock, 0, "Use cpus_read_lock() to exclude CPU hotplug.");
torture_param(int, verbose, 0, "Enable verbose debugging printk()s");
torture_param(int, weight_resched, -1, "Testing weight for resched_cpu() operations.");
torture_param(int, weight_single, -1, "Testing weight for single-CPU no-wait operations.");
torture_param(int, weight_single_wait, -1, "Testing weight for single-CPU operations.");
torture_param(int, weight_many, -1, "Testing weight for multi-CPU no-wait operations.");
Expand All @@ -82,6 +83,7 @@ torture_param(bool, shutdown, SCFTORT_SHUTDOWN, "Shutdown at end of torture test
struct scf_statistics {
struct task_struct *task;
int cpu;
long long n_resched;
long long n_single;
long long n_single_ofl;
long long n_single_wait;
Expand All @@ -97,12 +99,15 @@ static struct task_struct *scf_torture_stats_task;
static DEFINE_PER_CPU(long long, scf_invoked_count);

// Data for random primitive selection
#define SCF_PRIM_SINGLE 0
#define SCF_PRIM_MANY 1
#define SCF_PRIM_ALL 2
#define SCF_NPRIMS (2 * 3) // Need wait and no-wait versions of each.
#define SCF_PRIM_RESCHED 0
#define SCF_PRIM_SINGLE 1
#define SCF_PRIM_MANY 2
#define SCF_PRIM_ALL 3
#define SCF_NPRIMS 7 // Need wait and no-wait versions of each,
// except for SCF_PRIM_RESCHED.

static char *scf_prim_name[] = {
"resched_cpu",
"smp_call_function_single",
"smp_call_function_many",
"smp_call_function",
Expand Down Expand Up @@ -136,6 +141,8 @@ static char *bangstr = "";

static DEFINE_TORTURE_RANDOM_PERCPU(scf_torture_rand);

extern void resched_cpu(int cpu); // An alternative IPI vector.

// Print torture statistics. Caller must ensure serialization.
static void scf_torture_stats_print(void)
{
Expand All @@ -148,6 +155,7 @@ static void scf_torture_stats_print(void)
for_each_possible_cpu(cpu)
invoked_count += data_race(per_cpu(scf_invoked_count, cpu));
for (i = 0; i < nthreads; i++) {
scfs.n_resched += scf_stats_p[i].n_resched;
scfs.n_single += scf_stats_p[i].n_single;
scfs.n_single_ofl += scf_stats_p[i].n_single_ofl;
scfs.n_single_wait += scf_stats_p[i].n_single_wait;
Expand All @@ -160,8 +168,8 @@ static void scf_torture_stats_print(void)
if (atomic_read(&n_errs) || atomic_read(&n_mb_in_errs) ||
atomic_read(&n_mb_out_errs) || atomic_read(&n_alloc_errs))
bangstr = "!!! ";
pr_alert("%s %sscf_invoked_count %s: %lld single: %lld/%lld single_ofl: %lld/%lld many: %lld/%lld all: %lld/%lld ",
SCFTORT_FLAG, bangstr, isdone ? "VER" : "ver", invoked_count,
pr_alert("%s %sscf_invoked_count %s: %lld resched: %lld single: %lld/%lld single_ofl: %lld/%lld many: %lld/%lld all: %lld/%lld ",
SCFTORT_FLAG, bangstr, isdone ? "VER" : "ver", invoked_count, scfs.n_resched,
scfs.n_single, scfs.n_single_wait, scfs.n_single_ofl, scfs.n_single_wait_ofl,
scfs.n_many, scfs.n_many_wait, scfs.n_all, scfs.n_all_wait);
torture_onoff_stats();
Expand Down Expand Up @@ -314,6 +322,13 @@ static void scftorture_invoke_one(struct scf_statistics *scfp, struct torture_ra
}
}
switch (scfsp->scfs_prim) {
case SCF_PRIM_RESCHED:
if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST)) {
cpu = torture_random(trsp) % nr_cpu_ids;
scfp->n_resched++;
resched_cpu(cpu);
}
break;
case SCF_PRIM_SINGLE:
cpu = torture_random(trsp) % nr_cpu_ids;
if (scfsp->scfs_wait)
Expand Down Expand Up @@ -433,8 +448,8 @@ static void
scftorture_print_module_parms(const char *tag)
{
pr_alert(SCFTORT_FLAG
"--- %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_many=%d, weight_many_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag,
verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter_cpus, use_cpus_read_lock, weight_single, weight_single_wait, weight_many, weight_many_wait, weight_all, weight_all_wait);
"--- %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_resched=%d, weight_single=%d, weight_single_wait=%d, weight_many=%d, weight_many_wait=%d, weight_all=%d, weight_all_wait=%d\n", tag,
verbose, holdoff, longwait, nthreads, onoff_holdoff, onoff_interval, shutdown, stat_interval, stutter_cpus, use_cpus_read_lock, weight_resched, weight_single, weight_single_wait, weight_many, weight_many_wait, weight_all, weight_all_wait);
}

static void scf_cleanup_handler(void *unused)
Expand Down Expand Up @@ -475,6 +490,7 @@ static int __init scf_torture_init(void)
{
long i;
int firsterr = 0;
unsigned long weight_resched1 = weight_resched;
unsigned long weight_single1 = weight_single;
unsigned long weight_single_wait1 = weight_single_wait;
unsigned long weight_many1 = weight_many;
Expand All @@ -487,16 +503,19 @@ static int __init scf_torture_init(void)

scftorture_print_module_parms("Start of test");

if (weight_single == -1 && weight_single_wait == -1 &&
if (weight_resched == -1 && weight_single == -1 && weight_single_wait == -1 &&
weight_many == -1 && weight_many_wait == -1 &&
weight_all == -1 && weight_all_wait == -1) {
weight_resched1 = 2 * nr_cpu_ids;
weight_single1 = 2 * nr_cpu_ids;
weight_single_wait1 = 2 * nr_cpu_ids;
weight_many1 = 2;
weight_many_wait1 = 2;
weight_all1 = 1;
weight_all_wait1 = 1;
} else {
if (weight_resched == -1)
weight_resched1 = 0;
if (weight_single == -1)
weight_single1 = 0;
if (weight_single_wait == -1)
Expand All @@ -517,6 +536,10 @@ static int __init scf_torture_init(void)
firsterr = -EINVAL;
goto unwind;
}
if (IS_BUILTIN(CONFIG_SCF_TORTURE_TEST))
scf_sel_add(weight_resched1, SCF_PRIM_RESCHED, false);
else if (weight_resched1)
VERBOSE_SCFTORTOUT_ERRSTRING("built as module, weight_resched ignored");
scf_sel_add(weight_single1, SCF_PRIM_SINGLE, false);
scf_sel_add(weight_single_wait1, SCF_PRIM_SINGLE, true);
scf_sel_add(weight_many1, SCF_PRIM_MANY, false);
Expand Down

0 comments on commit 1ac78b4

Please sign in to comment.