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Merge branches 'doc.2019.12.10a', 'exp.2019.12.09a', 'fixes.2020.01.24a', 'kfree_rcu.2020.01.24a', 'list.2020.01.10a', 'preempt.2020.01.24a' and 'torture.2019.12.09a' into HEAD

Browse Source 
doc.2019.12.10a: Documentations updates
exp.2019.12.09a: Expedited grace-period updates
fixes.2020.01.24a: Miscellaneous fixes
kfree_rcu.2020.01.24a: Batch kfree_rcu() work
list.2020.01.10a: RCU-protected-list updates
preempt.2020.01.24a: Preemptible RCU updates
torture.2019.12.09a: Torture-test updates
This commit is contained in:
Paul E. McKenney
2020-01-24 10:37:27 -08:00
parent 6e6eca2ee7 df1e849ae4 f6105fc2a9 189a6883dc afa47fdfa2 5b14557b07 b22eb7cefb
commit 0e247386d9
39 changed files with 1070 additions and 575 deletions
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141
kernel/rcu/rcutorture.c
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@@ -1661,43 +1661,52 @@ static void rcu_torture_fwd_prog_cb(struct rcu_head *rhp)
struct rcu_fwd_cb {
struct rcu_head rh;
struct rcu_fwd_cb *rfc_next;
struct rcu_fwd *rfc_rfp;
int rfc_gps;
};
static DEFINE_SPINLOCK(rcu_fwd_lock);
static struct rcu_fwd_cb *rcu_fwd_cb_head;
static struct rcu_fwd_cb **rcu_fwd_cb_tail = &rcu_fwd_cb_head;
static long n_launders_cb;
static unsigned long rcu_fwd_startat;
static bool rcu_fwd_emergency_stop;
#define MAX_FWD_CB_JIFFIES (8 * HZ) /* Maximum CB test duration. */
#define MIN_FWD_CB_LAUNDERS 3 /* This many CB invocations to count. */
#define MIN_FWD_CBS_LAUNDERED 100 /* Number of counted CBs. */
#define FWD_CBS_HIST_DIV 10 /* Histogram buckets/second. */
#define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
struct rcu_launder_hist {
long n_launders;
unsigned long launder_gp_seq;
};
#define N_LAUNDERS_HIST (2 * MAX_FWD_CB_JIFFIES / (HZ / FWD_CBS_HIST_DIV))
static struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
static unsigned long rcu_launder_gp_seq_start;
static void rcu_torture_fwd_cb_hist(void)
struct rcu_fwd {
spinlock_t rcu_fwd_lock;
struct rcu_fwd_cb *rcu_fwd_cb_head;
struct rcu_fwd_cb **rcu_fwd_cb_tail;
long n_launders_cb;
unsigned long rcu_fwd_startat;
struct rcu_launder_hist n_launders_hist[N_LAUNDERS_HIST];
unsigned long rcu_launder_gp_seq_start;
};
struct rcu_fwd *rcu_fwds;
bool rcu_fwd_emergency_stop;
static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
{
unsigned long gps;
unsigned long gps_old;
int i;
int j;
for (i = ARRAY_SIZE(n_launders_hist) - 1; i > 0; i--)
if (n_launders_hist[i].n_launders > 0)
for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
if (rfp->n_launders_hist[i].n_launders > 0)
break;
pr_alert("%s: Callback-invocation histogram (duration %lu jiffies):",
__func__, jiffies - rcu_fwd_startat);
gps_old = rcu_launder_gp_seq_start;
__func__, jiffies - rfp->rcu_fwd_startat);
gps_old = rfp->rcu_launder_gp_seq_start;
for (j = 0; j <= i; j++) {
gps = n_launders_hist[j].launder_gp_seq;
gps = rfp->n_launders_hist[j].launder_gp_seq;
pr_cont(" %ds/%d: %ld:%ld",
j + 1, FWD_CBS_HIST_DIV, n_launders_hist[j].n_launders,
j + 1, FWD_CBS_HIST_DIV,
rfp->n_launders_hist[j].n_launders,
rcutorture_seq_diff(gps, gps_old));
gps_old = gps;
}
@@ -1711,26 +1720,27 @@ static void rcu_torture_fwd_cb_cr(struct rcu_head *rhp)
int i;
struct rcu_fwd_cb *rfcp = container_of(rhp, struct rcu_fwd_cb, rh);
struct rcu_fwd_cb **rfcpp;
struct rcu_fwd *rfp = rfcp->rfc_rfp;
rfcp->rfc_next = NULL;
rfcp->rfc_gps++;
spin_lock_irqsave(&rcu_fwd_lock, flags);
rfcpp = rcu_fwd_cb_tail;
rcu_fwd_cb_tail = &rfcp->rfc_next;
spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
rfcpp = rfp->rcu_fwd_cb_tail;
rfp->rcu_fwd_cb_tail = &rfcp->rfc_next;
WRITE_ONCE(*rfcpp, rfcp);
WRITE_ONCE(n_launders_cb, n_launders_cb + 1);
i = ((jiffies - rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
if (i >= ARRAY_SIZE(n_launders_hist))
i = ARRAY_SIZE(n_launders_hist) - 1;
n_launders_hist[i].n_launders++;
n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
spin_unlock_irqrestore(&rcu_fwd_lock, flags);
WRITE_ONCE(rfp->n_launders_cb, rfp->n_launders_cb + 1);
i = ((jiffies - rfp->rcu_fwd_startat) / (HZ / FWD_CBS_HIST_DIV));
if (i >= ARRAY_SIZE(rfp->n_launders_hist))
i = ARRAY_SIZE(rfp->n_launders_hist) - 1;
rfp->n_launders_hist[i].n_launders++;
rfp->n_launders_hist[i].launder_gp_seq = cur_ops->get_gp_seq();
spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
}
// Give the scheduler a chance, even on nohz_full CPUs.
static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
{
if (IS_ENABLED(CONFIG_PREEMPT) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
if (IS_ENABLED(CONFIG_PREEMPTION) && IS_ENABLED(CONFIG_NO_HZ_FULL)) {
// Real call_rcu() floods hit userspace, so emulate that.
if (need_resched() || (iter & 0xfff))
schedule();
@@ -1744,23 +1754,23 @@ static void rcu_torture_fwd_prog_cond_resched(unsigned long iter)
* Free all callbacks on the rcu_fwd_cb_head list, either because the
* test is over or because we hit an OOM event.
*/
static unsigned long rcu_torture_fwd_prog_cbfree(void)
static unsigned long rcu_torture_fwd_prog_cbfree(struct rcu_fwd *rfp)
{
unsigned long flags;
unsigned long freed = 0;
struct rcu_fwd_cb *rfcp;
for (;;) {
spin_lock_irqsave(&rcu_fwd_lock, flags);
rfcp = rcu_fwd_cb_head;
spin_lock_irqsave(&rfp->rcu_fwd_lock, flags);
rfcp = rfp->rcu_fwd_cb_head;
if (!rfcp) {
spin_unlock_irqrestore(&rcu_fwd_lock, flags);
spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
break;
}
rcu_fwd_cb_head = rfcp->rfc_next;
if (!rcu_fwd_cb_head)
rcu_fwd_cb_tail = &rcu_fwd_cb_head;
spin_unlock_irqrestore(&rcu_fwd_lock, flags);
rfp->rcu_fwd_cb_head = rfcp->rfc_next;
if (!rfp->rcu_fwd_cb_head)
rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
spin_unlock_irqrestore(&rfp->rcu_fwd_lock, flags);
kfree(rfcp);
freed++;
rcu_torture_fwd_prog_cond_resched(freed);
@@ -1774,7 +1784,8 @@ static unsigned long rcu_torture_fwd_prog_cbfree(void)
}
/* Carry out need_resched()/cond_resched() forward-progress testing. */
static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries)
static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
int *tested, int *tested_tries)
{
unsigned long cver;
unsigned long dur;
@@ -1804,8 +1815,8 @@ static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries)
sd = cur_ops->stall_dur() + 1;
sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
dur = sd4 + torture_random(&trs) % (sd - sd4);
WRITE_ONCE(rcu_fwd_startat, jiffies);
stopat = rcu_fwd_startat + dur;
WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
stopat = rfp->rcu_fwd_startat + dur;
while (time_before(jiffies, stopat) &&
!shutdown_time_arrived() &&
!READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
@@ -1840,7 +1851,7 @@ static void rcu_torture_fwd_prog_nr(int *tested, int *tested_tries)
}
/* Carry out call_rcu() forward-progress testing. */
static void rcu_torture_fwd_prog_cr(void)
static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
{
unsigned long cver;
unsigned long flags;
@@ -1864,23 +1875,23 @@ static void rcu_torture_fwd_prog_cr(void)
/* Loop continuously posting RCU callbacks. */
WRITE_ONCE(rcu_fwd_cb_nodelay, true);
cur_ops->sync(); /* Later readers see above write. */
WRITE_ONCE(rcu_fwd_startat, jiffies);
stopat = rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
n_launders = 0;
n_launders_cb = 0;
rfp->n_launders_cb = 0; // Hoist initialization for multi-kthread
n_launders_sa = 0;
n_max_cbs = 0;
n_max_gps = 0;
for (i = 0; i < ARRAY_SIZE(n_launders_hist); i++)
n_launders_hist[i].n_launders = 0;
for (i = 0; i < ARRAY_SIZE(rfp->n_launders_hist); i++)
rfp->n_launders_hist[i].n_launders = 0;
cver = READ_ONCE(rcu_torture_current_version);
gps = cur_ops->get_gp_seq();
rcu_launder_gp_seq_start = gps;
rfp->rcu_launder_gp_seq_start = gps;
tick_dep_set_task(current, TICK_DEP_BIT_RCU);
while (time_before(jiffies, stopat) &&
!shutdown_time_arrived() &&
!READ_ONCE(rcu_fwd_emergency_stop) && !torture_must_stop()) {
rfcp = READ_ONCE(rcu_fwd_cb_head);
rfcp = READ_ONCE(rfp->rcu_fwd_cb_head);
rfcpn = NULL;
if (rfcp)
rfcpn = READ_ONCE(rfcp->rfc_next);
@@ -1888,7 +1899,7 @@ static void rcu_torture_fwd_prog_cr(void)
if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
break;
rcu_fwd_cb_head = rfcpn;
rfp->rcu_fwd_cb_head = rfcpn;
n_launders++;
n_launders_sa++;
} else {
@@ -1900,6 +1911,7 @@ static void rcu_torture_fwd_prog_cr(void)
n_max_cbs++;
n_launders_sa = 0;
rfcp->rfc_gps = 0;
rfcp->rfc_rfp = rfp;
}
cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
rcu_torture_fwd_prog_cond_resched(n_launders + n_max_cbs);
@@ -1910,22 +1922,22 @@ static void rcu_torture_fwd_prog_cr(void)
}
}
stoppedat = jiffies;
n_launders_cb_snap = READ_ONCE(n_launders_cb);
n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
cver = READ_ONCE(rcu_torture_current_version) - cver;
gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
(void)rcu_torture_fwd_prog_cbfree();
(void)rcu_torture_fwd_prog_cbfree(rfp);
if (!torture_must_stop() && !READ_ONCE(rcu_fwd_emergency_stop) &&
!shutdown_time_arrived()) {
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 - rfp->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);
rcu_torture_fwd_cb_hist();
rcu_torture_fwd_cb_hist(rfp);
}
schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
@@ -1940,20 +1952,22 @@ static void rcu_torture_fwd_prog_cr(void)
static int rcutorture_oom_notify(struct notifier_block *self,
unsigned long notused, void *nfreed)
{
struct rcu_fwd *rfp = rcu_fwds;
WARN(1, "%s invoked upon OOM during forward-progress testing.\n",
__func__);
rcu_torture_fwd_cb_hist();
rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rcu_fwd_startat)) / 2);
rcu_torture_fwd_cb_hist(rfp);
rcu_fwd_progress_check(1 + (jiffies - READ_ONCE(rfp->rcu_fwd_startat)) / 2);
WRITE_ONCE(rcu_fwd_emergency_stop, true);
smp_mb(); /* Emergency stop before free and wait to avoid hangs. */
pr_info("%s: Freed %lu RCU callbacks.\n",
__func__, rcu_torture_fwd_prog_cbfree());
__func__, rcu_torture_fwd_prog_cbfree(rfp));
rcu_barrier();
pr_info("%s: Freed %lu RCU callbacks.\n",
__func__, rcu_torture_fwd_prog_cbfree());
__func__, rcu_torture_fwd_prog_cbfree(rfp));
rcu_barrier();
pr_info("%s: Freed %lu RCU callbacks.\n",
__func__, rcu_torture_fwd_prog_cbfree());
__func__, rcu_torture_fwd_prog_cbfree(rfp));
smp_mb(); /* Frees before return to avoid redoing OOM. */
(*(unsigned long *)nfreed)++; /* Forward progress CBs freed! */
pr_info("%s returning after OOM processing.\n", __func__);
@@ -1967,6 +1981,7 @@ static struct notifier_block rcutorture_oom_nb = {
/* Carry out grace-period forward-progress testing. */
static int rcu_torture_fwd_prog(void *args)
{
struct rcu_fwd *rfp = args;
int tested = 0;
int tested_tries = 0;
@@ -1978,8 +1993,8 @@ static int rcu_torture_fwd_prog(void *args)
schedule_timeout_interruptible(fwd_progress_holdoff * HZ);
WRITE_ONCE(rcu_fwd_emergency_stop, false);
register_oom_notifier(&rcutorture_oom_nb);
rcu_torture_fwd_prog_nr(&tested, &tested_tries);
rcu_torture_fwd_prog_cr();
rcu_torture_fwd_prog_nr(rfp, &tested, &tested_tries);
rcu_torture_fwd_prog_cr(rfp);
unregister_oom_notifier(&rcutorture_oom_nb);
/* Avoid slow periods, better to test when busy. */
@@ -1995,6 +2010,8 @@ static int rcu_torture_fwd_prog(void *args)
/* If forward-progress checking is requested and feasible, spawn the thread. */
static int __init rcu_torture_fwd_prog_init(void)
{
struct rcu_fwd *rfp;
if (!fwd_progress)
return 0; /* Not requested, so don't do it. */
if (!cur_ops->stall_dur || cur_ops->stall_dur() <= 0 ||
@@ -2013,8 +2030,12 @@ static int __init rcu_torture_fwd_prog_init(void)
fwd_progress_holdoff = 1;
if (fwd_progress_div <= 0)
fwd_progress_div = 4;
return torture_create_kthread(rcu_torture_fwd_prog,
NULL, fwd_prog_task);
rfp = kzalloc(sizeof(*rfp), GFP_KERNEL);
if (!rfp)
return -ENOMEM;
spin_lock_init(&rfp->rcu_fwd_lock);
rfp->rcu_fwd_cb_tail = &rfp->rcu_fwd_cb_head;
return torture_create_kthread(rcu_torture_fwd_prog, rfp, fwd_prog_task);
}
/* Callback function for RCU barrier testing. */