Changeset c124c985 in mainline for uspace/lib/c/generic/fibril.c

Timestamp:

2018-07-16T15:38:16Z (6 years ago)

Author:

Jiří Zárevúcky <jiri.zarevucky@…>

Branches:

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

Children:

38d8849

Parents:

c45dc5e1

git-author:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-07-13 23:18:58)

git-committer:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-07-16 15:38:16)

Message:

Add fibril_rmutex_t type and fibril multithreading enablement.

File:

• uspace/lib/c/generic/fibril.c (modified) (1 diff)

uspace/lib/c/generic/fibril.c

@@ -344 +344 @@
 }
 
+static void _runner_fn(void *arg)
+{
+        futex_lock(&async_futex);
+        (void) fibril_switch(FIBRIL_FROM_BLOCKED);
+        __builtin_unreachable();
+}
+
+/**
+ * Spawn a given number of runners (i.e. OS threads) immediately, and
+ * unconditionally. This is meant to be used for tests and debugging.
+ * Regular programs should just use `fibril_enable_multithreaded()`.
+ *
+ * @param n  Number of runners to spawn.
+ * @return   Number of runners successfully spawned.
+ */
+int fibril_test_spawn_runners(int n)
+{
+        errno_t rc;
+
+        for (int i = 0; i < n; i++) {
+                thread_id_t tid;
+                rc = thread_create(_runner_fn, NULL, "fibril runner", &tid);
+                if (rc != EOK)
+                        return i;
+                thread_detach(tid);
+        }
+
+        return n;
+}
+
+/**
+ * Opt-in to have more than one runner thread.
+ *
+ * Currently, a task only ever runs in one thread because multithreading
+ * might break some existing code.
+ *
+ * Eventually, the number of runner threads for a given task should become
+ * configurable in the environment and this function becomes no-op.
+ */
+void fibril_enable_multithreaded(void)
+{
+        // TODO: Implement better.
+        //       For now, 4 total runners is a sensible default.
+        fibril_test_spawn_runners(3);
+}
+
+/**
+ * Detach a fibril.
+ */
+void fibril_detach(fid_t f)
+{
+        // TODO: Currently all fibrils are detached by default, but they
+        //       won't always be. Code that explicitly spawns fibrils with
+        //       limited lifetime should call this function.
+}
+
 /** @}
  */