Changeset 2965d18 in mainline

Timestamp:

2018-07-30T20:15:38Z (6 years ago)

Author:

Jiří Zárevúcky <jiri.zarevucky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

d4b7b29

Parents:

8080262

git-author:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-07-30 19:53:13)

git-committer:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-07-30 20:15:38)

Message:

Add debug counter for rmutex locks.

Location:

uspace/lib/c

Files:

• generic/fibril.c (modified) (5 diffs)
• generic/fibril_synch.c (modified) (1 diff)
• generic/futex.c (modified) (6 diffs)
• generic/private/fibril.h (modified) (1 diff)
• include/fibril_synch.h (modified) (2 diffs)
• include/io/kio.h (modified) (1 diff)

uspace/lib/c/generic/fibril.c

@@ -476 +476 @@
 static void _fibril_switch_to(_switch_type_t type, fibril_t *dstf, bool locked)
 {
+        assert(fibril_self()->rmutex_locks == 0);
+
         if (!locked)
                 futex_lock(&fibril_futex);
@@ -633 +635 @@
 errno_t fibril_wait_timeout(fibril_event_t *event, const struct timeval *expires)
 {
+        assert(fibril_self()->rmutex_locks == 0);
+
         DPRINTF("### Fibril %p sleeping on event %p.\n", fibril_self(), event);
 
@@ -713 +717 @@
 void fibril_wait_for(fibril_event_t *event)
 {
+        assert(fibril_self()->rmutex_locks == 0);
+
         (void) fibril_wait_timeout(event, NULL);
 }
@@ -769 +775 @@
 void fibril_yield(void)
 {
+        if (fibril_self()->rmutex_locks > 0)
+                return;
+
         fibril_t *f = _ready_list_pop_nonblocking(false);
         if (f)
@@ -789 +798 @@
 int fibril_test_spawn_runners(int n)
 {
+        assert(fibril_self()->rmutex_locks == 0);
+
         if (!multithreaded) {
                 _ready_debug_check();

uspace/lib/c/generic/fibril_synch.c

@@ -50 +50 @@
 #include "private/async.h"
 #include "private/fibril.h"
+
+void fibril_rmutex_initialize(fibril_rmutex_t *m)
+{
+        futex_initialize(&m->futex, 1);
+}
+
+/**
+ * Lock restricted mutex.
+ * When a restricted mutex is locked, the fibril may not sleep or create new
+ * threads. Any attempt to do so will abort the program.
+ */
+void fibril_rmutex_lock(fibril_rmutex_t *m)
+{
+        futex_lock(&m->futex);
+        fibril_self()->rmutex_locks++;
+}
+
+bool fibril_rmutex_trylock(fibril_rmutex_t *m)
+{
+        if (futex_trylock(&m->futex)) {
+                fibril_self()->rmutex_locks++;
+                return true;
+        } else {
+                return false;
+        }
+}
+
+void fibril_rmutex_unlock(fibril_rmutex_t *m)
+{
+        fibril_self()->rmutex_locks--;
+        futex_unlock(&m->futex);
+}
 
 static fibril_local bool deadlocked = false;

uspace/lib/c/generic/futex.c

@@ -43 +43 @@
 
 //#define DPRINTF(...) kio_printf(__VA_ARGS__)
-#define DPRINTF(...) ((void)0)
+#define DPRINTF(...) dummy_printf(__VA_ARGS__)
 
 /** Initialize futex counter.
@@ -84 +84 @@
          * They should compile to regular load/stores, but simple assignments
          * would be UB by definition.
+         * The proper ordering is ensured by the surrounding futex operation.
          */
 
@@ -94 +95 @@
         assert(prev_owner == NULL);
         __atomic_store_n(&futex->owner, self, __ATOMIC_RELAXED);
-
-        atomic_inc(&self->futex_locks);
 }
 
@@ -104 +103 @@
         __futex_assert_is_locked(futex, name);
         __atomic_store_n(&futex->owner, NULL, __ATOMIC_RELAXED);
-        atomic_dec(&self->futex_locks);
         futex_up(futex);
 }
@@ -117 +115 @@
 
                 __atomic_store_n(&futex->owner, self, __ATOMIC_RELAXED);
-
-                atomic_inc(&self->futex_locks);
 
                 DPRINTF("Trylock on futex %s (%p) by fibril %p succeeded.\n", name, futex, self);
@@ -135 +131 @@
 
         __futex_assert_is_locked(futex, name);
-        atomic_dec(&self->futex_locks);
-        atomic_inc(&no->futex_locks);
         __atomic_store_n(&futex->owner, new_owner, __ATOMIC_RELAXED);
 }

uspace/lib/c/generic/private/fibril.h

@@ -61 +61 @@
 
         /* Debugging stuff. */
-        atomic_t futex_locks;
+        int rmutex_locks;
         fibril_owner_info_t *waits_for;
         fibril_event_t *sleep_event;

uspace/lib/c/include/fibril_synch.h

@@ -80 +80 @@
 #define FIBRIL_RMUTEX_INITIALIZE(name) \
         fibril_rmutex_t name = FIBRIL_RMUTEX_INITIALIZER(name)
-
-static inline void fibril_rmutex_initialize(fibril_rmutex_t *m)
-{
-        futex_initialize(&m->futex, 1);
-}
-
-static inline void fibril_rmutex_lock(fibril_rmutex_t *m)
-{
-        futex_lock(&m->futex);
-}
-
-static inline bool fibril_rmutex_trylock(fibril_rmutex_t *m)
-{
-        return futex_trylock(&m->futex);
-}
-
-static inline void fibril_rmutex_unlock(fibril_rmutex_t *m)
-{
-        futex_unlock(&m->futex);
-}
 
 typedef struct {
@@ -222 +202 @@
         fibril_semaphore_t name = FIBRIL_SEMAPHORE_INITIALIZER(name, cnt)
 
+extern void fibril_rmutex_initialize(fibril_rmutex_t *);
+extern void fibril_rmutex_lock(fibril_rmutex_t *);
+extern bool fibril_rmutex_trylock(fibril_rmutex_t *);
+extern void fibril_rmutex_unlock(fibril_rmutex_t *);
+
 extern void fibril_mutex_initialize(fibril_mutex_t *);
 extern void fibril_mutex_lock(fibril_mutex_t *);

uspace/lib/c/include/io/kio.h

@@ -49 +49 @@
 extern int kio_vprintf(const char *, va_list);
 
+/*
+ * In some files, we have conditional DPRINTF(...) macro that is defined empty
+ * in most cases. Provide a dummy printf so we get argument checking and
+ * avoid unused variable errors.
+ */
+
+static inline int dummy_printf(const char *fmt, ...) _HELENOS_PRINTF_ATTRIBUTE(1, 2);
+static inline int dummy_printf(const char *fmt, ...)
+{
+        /* Empty. */
+        (void) fmt;
+        return 0;
+}
+
 #endif