refperf: Dynamically allocate experiment-summary output buffer

Currently, the buffer used to accumulate the experiment-summary output
is fixed size, which will cause problems if someone decides to run
one hundred experiments.  This commit therefore dynamically allocates
this buffer.

Cc: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/refperf.c b/kernel/rcu/refperf.c
index 6324449db4048d31f5d3d9ddc21cd76a9b40e4d5..75b9cceaece1303f818ef1f5a6ef3e5ea0a72eed 100644 (file)
--- a/kernel/rcu/refperf.c
+++ b/kernel/rcu/refperf.c
@@ -333,9 +333,10 @@ u64 process_durations(int n)
 // point all the timestamps are printed.
 static int main_func(void *arg)
 {
+       bool errexit = false;
        int exp, r;
        char buf1[64];
-       char buf[512];
+       char *buf;
        u64 *result_avg;
 
        set_cpus_allowed_ptr(current, cpumask_of(nreaders % nr_cpu_ids));
@@ -343,8 +344,11 @@ static int main_func(void *arg)
 
        VERBOSE_PERFOUT("main_func task started");
        result_avg = kzalloc(nruns * sizeof(*result_avg), GFP_KERNEL);
-       if (!result_avg)
+       buf = kzalloc(64 + nruns * 32, GFP_KERNEL);
+       if (!result_avg || !buf) {
                VERBOSE_PERFOUT_ERRSTRING("out of memory");
+               errexit = true;
+       }
        atomic_inc(&n_init);
 
        // Wait for all threads to start.
@@ -354,7 +358,7 @@ static int main_func(void *arg)
 
        // Start exp readers up per experiment
        for (exp = 0; exp < nruns && !torture_must_stop(); exp++) {
-               if (!result_avg)
+               if (errexit)
                        break;
                if (torture_must_stop())
                        goto end;
@@ -391,13 +395,13 @@ static int main_func(void *arg)
        strcat(buf, "Threads\tTime(ns)\n");
 
        for (exp = 0; exp < nruns; exp++) {
-               if (!result_avg)
+               if (errexit)
                        break;
                sprintf(buf1, "%d\t%llu.%03d\n", exp + 1, result_avg[exp] / 1000, (int)(result_avg[exp] % 1000));
                strcat(buf, buf1);
        }
 
-       if (result_avg)
+       if (!errexit)
                PERFOUT("%s", buf);
 
        // This will shutdown everything including us.
@@ -412,6 +416,8 @@ static int main_func(void *arg)
 
 end:
        torture_kthread_stopping("main_func");
+       kfree(result_avg);
+       kfree(buf);
        return 0;
 }