]> asedeno.scripts.mit.edu Git - linux.git/commitdiff
rcutorture: Break up too-long rcu_torture_fwd_prog() function
authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Tue, 28 Aug 2018 21:38:43 +0000 (14:38 -0700)
committerPaul E. McKenney <paulmck@linux.ibm.com>
Sat, 1 Dec 2018 20:45:34 +0000 (12:45 -0800)
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>
kernel/rcu/rcutorture.c

index 17f480129a780112e9c60d991bcef00e2aa97ca6..bcc33bb8d9a69ea188d8c9bd623520f18b21dbbb 100644 (file)
@@ -1650,15 +1650,70 @@ 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 sd;
+       int sd4;
+       bool selfpropcb = false;
+       unsigned long stopat;
+       static DEFINE_TORTURE_RANDOM(trs);
+
+       if  (cur_ops->call && cur_ops->sync && cur_ops->cb_barrier) {
+               init_rcu_head_on_stack(&fcs.rh);
+               selfpropcb = true;
+       }
+
+       /* Tight loop containing cond_resched(). */
+       if  (selfpropcb) {
+               WRITE_ONCE(fcs.stop, 0);
+               cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
+       }
+       cver = READ_ONCE(rcu_torture_current_version);
+       gps = cur_ops->get_gp_seq();
+       sd = cur_ops->stall_dur() + 1;
+       sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
+       dur = sd4 + torture_random(&trs) % (sd - sd4);
+       rcu_fwd_startat = jiffies;
+       stopat = rcu_fwd_startat + dur;
+       while (time_before(jiffies, stopat) && !torture_must_stop()) {
+               idx = cur_ops->readlock();
+               udelay(10);
+               cur_ops->readunlock(idx);
+               if (!fwd_progress_need_resched || need_resched())
+                       cond_resched();
+       }
+       (*tested_tries)++;
+       if (!time_before(jiffies, stopat) && !torture_must_stop()) {
+               (*tested)++;
+               cver = READ_ONCE(rcu_torture_current_version) - cver;
+               gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
+               WARN_ON(!cver && gps < 2);
+               pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps);
+       }
+       if (selfpropcb) {
+               WRITE_ONCE(fcs.stop, 1);
+               cur_ops->sync(); /* Wait for running CB to complete. */
+               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;
@@ -1667,136 +1722,97 @@ static int rcu_torture_fwd_prog(void *args)
        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;
+
+       /* Loop continuously posting RCU callbacks. */
+       WRITE_ONCE(rcu_fwd_cb_nodelay, true);
+       cur_ops->sync(); /* Later readers see above write. */
+       rcu_fwd_startat = jiffies;
+       stopat = rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
+       n_launders = 0;
+       n_launders_cb = 0;
+       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] = 0;
+       cver = READ_ONCE(rcu_torture_current_version);
+       gps = cur_ops->get_gp_seq();
+       while (time_before(jiffies, stopat) && !torture_must_stop()) {
+               rfcp = READ_ONCE(rcu_fwd_cb_head);
+               rfcpn = NULL;
+               if (rfcp)
+                       rfcpn = READ_ONCE(rfcp->rfc_next);
+               if (rfcpn) {
+                       if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
+                           ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
+                               break;
+                       rcu_fwd_cb_head = rfcpn;
+                       n_launders++;
+                       n_launders_sa++;
+               } else {
+                       rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
+                       if (WARN_ON_ONCE(!rfcp)) {
+                               schedule_timeout_interruptible(1);
+                               continue;
+                       }
+                       n_max_cbs++;
+                       n_launders_sa = 0;
+                       rfcp->rfc_gps = 0;
+               }
+               cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
+               cond_resched();
+       }
+       stoppedat = jiffies;
+       n_launders_cb_snap = READ_ONCE(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. */
+       for (;;) {
+               rfcp = rcu_fwd_cb_head;
+               if (!rfcp)
+                       break;
+               rcu_fwd_cb_head = rfcp->rfc_next;
+               kfree(rfcp);
+       }
+       rcu_fwd_cb_tail = &rcu_fwd_cb_head;
+       WRITE_ONCE(rcu_fwd_cb_nodelay, false);
+       if (!torture_must_stop()) {
+               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,
+                        n_launders + n_max_cbs - n_launders_cb_snap,
+                        n_launders, n_launders_sa,
+                        n_max_gps, n_max_cbs, cver, gps);
+               for (i = ARRAY_SIZE(n_launders_hist) - 1; i > 0; i--)
+                       if (n_launders_hist[i] > 0)
+                               break;
+               pr_alert("Callback-invocation histogram:");
+               for (j = 0; j <= i; j++)
+                       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;
-       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) {
-                       WRITE_ONCE(fcs.stop, 0);
-                       cur_ops->call(&fcs.rh, rcu_torture_fwd_prog_cb);
-               }
-               cver = READ_ONCE(rcu_torture_current_version);
-               gps = cur_ops->get_gp_seq();
-               sd = cur_ops->stall_dur() + 1;
-               sd4 = (sd + fwd_progress_div - 1) / fwd_progress_div;
-               dur = sd4 + torture_random(&trs) % (sd - sd4);
-               rcu_fwd_startat = jiffies;
-               stopat = rcu_fwd_startat + dur;
-               while (time_before(jiffies, stopat) && !torture_must_stop()) {
-                       idx = cur_ops->readlock();
-                       udelay(10);
-                       cur_ops->readunlock(idx);
-                       if (!fwd_progress_need_resched || need_resched())
-                               cond_resched();
-               }
-               tested_tries++;
-               if (!time_before(jiffies, stopat) && !torture_must_stop()) {
-                       tested++;
-                       cver = READ_ONCE(rcu_torture_current_version) - cver;
-                       gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
-                       WARN_ON(!cver && gps < 2);
-                       pr_alert("%s: Duration %ld cver %ld gps %ld\n", __func__, dur, cver, gps);
-               }
-               if (selfpropcb) {
-                       WRITE_ONCE(fcs.stop, 1);
-                       cur_ops->sync(); /* Wait for running CB to complete. */
-                       cur_ops->cb_barrier(); /* Wait for queued callbacks. */
-               }
-
-               /* Loop continuously posting RCU callbacks. */
-               WRITE_ONCE(rcu_fwd_cb_nodelay, true);
-               cur_ops->sync(); /* Later readers see above write. */
-               rcu_fwd_startat = jiffies;
-               stopat = rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
-               n_launders = 0;
-               n_launders_cb = 0;
-               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] = 0;
-               cver = READ_ONCE(rcu_torture_current_version);
-               gps = cur_ops->get_gp_seq();
-               while (time_before(jiffies, stopat) && !torture_must_stop()) {
-                       rfcp = READ_ONCE(rcu_fwd_cb_head);
-                       rfcpn = NULL;
-                       if (rfcp)
-                               rfcpn = READ_ONCE(rfcp->rfc_next);
-                       if (rfcpn) {
-                               if (rfcp->rfc_gps >= MIN_FWD_CB_LAUNDERS &&
-                                   ++n_max_gps >= MIN_FWD_CBS_LAUNDERED)
-                                       break;
-                               rcu_fwd_cb_head = rfcpn;
-                               n_launders++;
-                               n_launders_sa++;
-                       } else {
-                               rfcp = kmalloc(sizeof(*rfcp), GFP_KERNEL);
-                               if (WARN_ON_ONCE(!rfcp)) {
-                                       schedule_timeout_interruptible(1);
-                                       continue;
-                               }
-                               n_max_cbs++;
-                               n_launders_sa = 0;
-                               rfcp->rfc_gps = 0;
-                       }
-                       cur_ops->call(&rfcp->rh, rcu_torture_fwd_cb_cr);
-                       cond_resched();
-               }
-               stoppedat = jiffies;
-               n_launders_cb_snap = READ_ONCE(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. */
-               for (;;) {
-                       rfcp = rcu_fwd_cb_head;
-                       if (!rfcp)
-                               break;
-                       rcu_fwd_cb_head = rfcp->rfc_next;
-                       kfree(rfcp);
-               }
-               rcu_fwd_cb_tail = &rcu_fwd_cb_head;
-               WRITE_ONCE(rcu_fwd_cb_nodelay, false);
-               if (!torture_must_stop()) {
-                       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,
-                                n_launders + n_max_cbs - n_launders_cb_snap,
-                                n_launders, n_launders_sa,
-                                n_max_gps, n_max_cbs, cver, gps);
-                       for (i = ARRAY_SIZE(n_launders_hist) - 1; i > 0; i--)
-                               if (n_launders_hist[i] > 0)
-                                       break;
-                       pr_alert("Callback-invocation histogram:");
-                       for (j = 0; j <= i; j++)
-                               pr_cont(" %ds: %ld", j + 1, n_launders_hist[j]);
-                       pr_cont("\n");
-               }
+               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);