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rcutorture: Break up too-long rcu_torture_fwd_prog() function

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This commit splits rcu_torture_fwd_prog_nr() and rcu_torture_fwd_prog_cr()
functions out of rcu_torture_fwd_prog() in order to reduce indentation
pain and because rcu_torture_fwd_prog() was getting a bit too long.
In addition, this will enable easier conditional execution of the
rcu_torture_fwd_prog_cr() function, which can give false-positive
failures in some NO_HZ_FULL configurations due to overloading the
housekeeping CPUs.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-08-28 14:38:43 -07:00 • committed by Paul E. McKenney
parent fc6f9c5778
commit 6b3de7a172
1 changed files with 135 additions and 119 deletions
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70
kernel/rcu/rcutorture.c
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@ -1650,41 +1650,24 @@ static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
spin_unlock(&rcu_fwd_lock);
}
/* Carry out grace-period forward-progress testing. */
static int rcu_torture_fwd_prog(void *args)
/* Carry out need_resched()/cond_resched() forward-progress testing. */
static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries)
{
unsigned long cver;
unsigned long dur;
struct fwd_cb_state fcs;
unsigned long gps;
int i;
int idx;
int j;
long n_launders;
long n_launders_cb_snap;
long n_launders_sa;
long n_max_cbs;
long n_max_gps;
struct rcu_fwd_cb *rfcp;
struct rcu_fwd_cb *rfcpn;
int sd;
int sd4;
bool selfpropcb = false;
unsigned long stopat;
unsigned long stoppedat;
int tested = 0;
int tested_tries = 0;
static DEFINE_TORTURE_RANDOM(trs);
VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
set_user_nice(current, MAX_NICE);
if (cur_ops->call && cur_ops->sync && cur_ops->cb_barrier) {
init_rcu_head_on_stack(&fcs.rh);
selfpropcb = true;
}
do {
schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
/* Tight loop containing cond_resched(). */
if (selfpropcb) {
@ -1705,9 +1688,9 @@ static int rcu_torture_fwd_prog(void *args)
if (!fwd_progress_need_resched || need_resched())
cond_resched();
}
tested_tries++;
(*tested_tries)++;
if (!time_before(jiffies, stopat) && !torture_must_stop()) {
tested++;
(*tested)++;
cver = READ_ONCE(rcu_torture_current_version) - cver;
gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
WARN_ON(!cver && gps < 2);
@ -1719,6 +1702,29 @@ static int rcu_torture_fwd_prog(void *args)
cur_ops->cb_barrier(); /* Wait for queued callbacks. */
}
if (selfpropcb) {
WARN_ON(READ_ONCE(fcs.stop) != 2);
destroy_rcu_head_on_stack(&fcs.rh);
}
}
/* Carry out call_rcu() forward-progress testing. */
static void rcu_torture_fwd_prog_cr(void)
{
unsigned long cver;
unsigned long gps;
int i;
int j;
long n_launders;
long n_launders_cb_snap;
long n_launders_sa;
long n_max_cbs;
long n_max_gps;
struct rcu_fwd_cb *rfcp;
struct rcu_fwd_cb *rfcpn;
unsigned long stopat;
unsigned long stoppedat;
/* Loop continuously posting RCU callbacks. */
WRITE_ONCE(rcu_fwd_cb_nodelay, true);
cur_ops->sync(); /* Later readers see above write. */
@ -1776,8 +1782,7 @@ static int rcu_torture_fwd_prog(void *args)
WARN_ON(n_max_gps < MIN_FWD_CBS_LAUNDERED);
pr_alert("%s Duration %lu barrier: %lu pending %ld n_launders: %ld n_launders_sa: %ld n_max_gps: %ld n_max_cbs: %ld cver %ld gps %ld\n",
__func__,
stoppedat - rcu_fwd_startat,
jiffies - stoppedat,
stoppedat - rcu_fwd_startat, jiffies - stoppedat,
n_launders + n_max_cbs - n_launders_cb_snap,
n_launders, n_launders_sa,
n_max_gps, n_max_cbs, cver, gps);
@ -1789,14 +1794,25 @@ static int rcu_torture_fwd_prog(void *args)
pr_cont(" %ds: %ld", j + 1, n_launders_hist[j]);
pr_cont("\n");
}
}
/* Carry out grace-period forward-progress testing. */
static int rcu_torture_fwd_prog(void *args)
{
int tested = 0;
int tested_tries = 0;
VERBOSE_TOROUT_STRING("rcu_torture_fwd_progress task started");
if (!IS_ENABLED(CONFIG_SMP) || !IS_ENABLED(CONFIG_RCU_BOOST))
set_user_nice(current, MAX_NICE);
do {
schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
rcu_torture_fwd_prog_nr(&tested, &tested_tries);
rcu_torture_fwd_prog_cr();
/* Avoid slow periods, better to test when busy. */
stutter_wait("rcu_torture_fwd_prog");
} while (!torture_must_stop());
if (selfpropcb) {
WARN_ON(READ_ONCE(fcs.stop) != 2);
destroy_rcu_head_on_stack(&fcs.rh);
}
/* Short runs might not contain a valid forward-progress attempt. */
WARN_ON(!tested && tested_tries >= 5);
pr_alert("%s: tested %d tested_tries %d\n", __func__, tested, tested_tries);