[coop] Improve logging and add a pair of suspend related due asserts.

Add asserts to both mono_threads_begin_global_suspend and mono_threads_end_global_suspend to ensure
balanced usage of the suspend semaphore.

The suspend semaphore must end a suspend operation at zero, meaning there must an equal number of
post and wait calls.

This ensure the initiator can't jump the gun when waiting for pending suspends by consuming a
post from a previous suspend/resume op.

diff --git a/mono/utils/mono-threads.c b/mono/utils/mono-threads.c
index 4b2bcdc6937683efc045e2e05bec08cb70942974..32fac7f04f3004d26e57b05c328b0bf927e95638 100644 (file)
--- a/mono/utils/mono-threads.c
+++ b/mono/utils/mono-threads.c
@@ -129,8 +129,9 @@ void
 mono_threads_begin_global_suspend (void)
 {
        g_assert (pending_suspends == 0);
-       THREADS_SUSPEND_DEBUG ("------ BEGIN GLOBAL OP sp %d rp %d ap %d wd %d po %d\n", suspend_posts, resume_posts,
+       THREADS_SUSPEND_DEBUG ("------ BEGIN GLOBAL OP sp %d rp %d ap %d wd %d po %d (sp + rp + ap == wd) (wd == po)\n", suspend_posts, resume_posts,
                abort_posts, waits_done, pending_ops);
+       g_assert ((suspend_posts + resume_posts + abort_posts) == waits_done);
        mono_threads_core_begin_global_suspend ();
 }
 
@@ -140,6 +141,7 @@ mono_threads_end_global_suspend (void)
        g_assert (pending_suspends == 0);
        THREADS_SUSPEND_DEBUG ("------ END GLOBAL OP sp %d rp %d ap %d wd %d po %d\n", suspend_posts, resume_posts,
                abort_posts, waits_done, pending_ops);
+       g_assert ((suspend_posts + resume_posts + abort_posts) == waits_done);
        mono_threads_core_end_global_suspend ();
 }
 
@@ -172,10 +174,10 @@ mono_threads_wait_pending_operations (void)
        int c = pending_suspends;
 
        /* Wait threads to park */
+       THREADS_SUSPEND_DEBUG ("[INITIATOR-WAIT-COUNT] %d\n", c);
        if (pending_suspends) {
                MonoStopwatch suspension_time;
                mono_stopwatch_start (&suspension_time);
-               THREADS_SUSPEND_DEBUG ("[INITIATOR-WAIT-COUNT] %d\n", c);
                for (i = 0; i < pending_suspends; ++i) {
                        THREADS_SUSPEND_DEBUG ("[INITIATOR-WAIT-WAITING]\n");
                        InterlockedIncrement (&waits_done);