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authorPaul E. McKenney <paulmck@kernel.org>2021-11-23 11:53:52 -0800
committerPaul E. McKenney <paulmck@kernel.org>2021-12-07 16:36:18 -0800
commit613b00fbe64461f1c73e035e07c22cf3de65740b (patch)
tree637ba4f0d889f584b22511e587d2f49b61a3933f /kernel/rcu/rcutorture.c
parent82e310033d7c21a7a88427f14e0dad78d731a5cd (diff)
rcutorture: Add ability to limit callback-flood intensity
The RCU tasks flavors of RCU now need concurrent callback flooding to test their ability to switch between single-queue mode and per-CPU queue mode, but their lack of heavy-duty forward-progress features rules out the use of rcutorture's current callback-flooding code. This commit therefore provides the ability to limit the intensity of the callback floods using a new ->cbflood_max field in the rcu_operations structure. When this field is zero, there is no limit, otherwise, each callback-flood kthread allocates at most ->cbflood_max callbacks. Cc: Neeraj Upadhyay <neeraj.iitr10@gmail.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu/rcutorture.c')
-rw-r--r--kernel/rcu/rcutorture.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 9390f867ba6c..1e8360d15920 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -348,6 +348,7 @@ struct rcu_torture_ops {
void (*gp_kthread_dbg)(void);
bool (*check_boost_failed)(unsigned long gp_state, int *cpup);
int (*stall_dur)(void);
+ long cbflood_max;
int irq_capable;
int can_boost;
int extendables;
@@ -841,6 +842,7 @@ static struct rcu_torture_ops tasks_rude_ops = {
.call = call_rcu_tasks_rude,
.cb_barrier = rcu_barrier_tasks_rude,
.gp_kthread_dbg = show_rcu_tasks_rude_gp_kthread,
+ .cbflood_max = 50000,
.fqs = NULL,
.stats = NULL,
.irq_capable = 1,
@@ -881,6 +883,7 @@ static struct rcu_torture_ops tasks_tracing_ops = {
.call = call_rcu_tasks_trace,
.cb_barrier = rcu_barrier_tasks_trace,
.gp_kthread_dbg = show_rcu_tasks_trace_gp_kthread,
+ .cbflood_max = 50000,
.fqs = NULL,
.stats = NULL,
.irq_capable = 1,
@@ -2387,7 +2390,7 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
rfp->rcu_fwd_cb_head = rfcpn;
n_launders++;
n_launders_sa++;
- } else {
+ } else if (!cur_ops->cbflood_max || cur_ops->cbflood_max > n_max_cbs) {
rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
if (WARN_ON_ONCE(!rfcp)) {
schedule_timeout_interruptible(1);
@@ -2397,8 +2400,11 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
n_launders_sa = 0;
rfcp->rfc_gps = 0;
rfcp->rfc_rfp = rfp;
+ } else {
+ rfcp = NULL;
}
- cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
+ if (rfcp)
+ cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
if (tick_nohz_full_enabled()) {
local_irq_save(flags);
@@ -2506,8 +2512,10 @@ static int rcu_torture_fwd_prog(void *args)
pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
if (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id)
rcu_torture_fwd_prog_cr(rfp);
- if (!IS_ENABLED(CONFIG_TINY_RCU) ||
- (rcu_inkernel_boot_has_ended() && torture_num_online_cpus() > rfp->rcu_fwd_id))
+ if ((cur_ops->stall_dur && cur_ops->stall_dur() > 0) &&
+ (!IS_ENABLED(CONFIG_TINY_RCU) ||
+ (rcu_inkernel_boot_has_ended() &&
+ torture_num_online_cpus() > rfp->rcu_fwd_id)))
rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
/* Avoid slow periods, better to test when busy. */
@@ -2539,7 +2547,8 @@ static int __init rcu_torture_fwd_prog_init(void)
fwd_progress = nr_cpu_ids;
}
if ((!cur_ops->sync && !cur_ops->call) ||
- !cur_ops->stall_dur || cur_ops->stall_dur() <= 0 || cur_ops == &rcu_busted_ops) {
+ (!cur_ops->cbflood_max && (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0)) ||
+ cur_ops == &rcu_busted_ops) {
VERBOSE_TOROUT_STRING("rcu_torture_fwd_prog_init: Disabled, unsupported by RCU flavor under test");
fwd_progress = 0;
return 0;

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