+/*
+ * Processor state is accessed by locking the scheduling lock
+ * for the assigned processor set.
+ *
+ * -------------------- SHUTDOWN
+ * / ^ ^
+ * _/ | \
+ * OFF_LINE ---> START ---> RUNNING ---> IDLE ---> DISPATCHING
+ * \_________________^ ^ ^______/ /
+ * \__________________/
+ *
+ * Most of these state transitions are externally driven as a
+ * a directive (for instance telling an IDLE processor to start
+ * coming out of the idle state to run a thread). However these
+ * are typically paired with a handshake by the processor itself
+ * to indicate that it has completed a transition of indeterminate
+ * length (for example, the DISPATCHING->RUNNING or START->RUNNING
+ * transitions must occur on the processor itself).
+ *
+ * The boot processor has some special cases, and skips the START state,
+ * since it has already bootstrapped and is ready to context switch threads.
+ *
+ * When a processor is in DISPATCHING or RUNNING state, the current_pri,
+ * current_thmode, and deadline fields should be set, so that other
+ * processors can evaluate if it is an appropriate candidate for preemption.
+ */
+#if defined(CONFIG_SCHED_DEFERRED_AST)
+/*
+ * -------------------- SHUTDOWN
+ * / ^ ^
+ * _/ | \
+ * OFF_LINE ---> START ---> RUNNING ---> IDLE ---> DISPATCHING
+ * \_________________^ ^ ^______/ ^_____ / /
+ * \__________________/
+ *
+ * A DISPATCHING processor may be put back into IDLE, if another
+ * processor determines that the target processor will have nothing to do
+ * upon reaching the RUNNING state. This is racy, but if the target
+ * responds and becomes RUNNING, it will not break the processor state
+ * machine.
+ *
+ * This change allows us to cancel an outstanding signal/AST on a processor
+ * (if such an operation is supported through hardware or software), and
+ * push the processor back into the IDLE state as a power optimization.
+ */
+#endif
+
+typedef enum {
+ PROCESSOR_OFF_LINE = 0, /* Not available */
+ PROCESSOR_SHUTDOWN = 1, /* Going off-line */
+ PROCESSOR_START = 2, /* Being started */
+ PROCESSOR_UNUSED = 3, /* Formerly Inactive (unavailable) */
+ PROCESSOR_IDLE = 4, /* Idle (available) */
+ PROCESSOR_DISPATCHING = 5, /* Dispatching (idle -> active) */
+ PROCESSOR_RUNNING = 6, /* Normal execution */
+ PROCESSOR_STATE_LEN = (PROCESSOR_RUNNING + 1)
+} processor_state_t;
+
+typedef enum {
+ PSET_SMP,
+#if __AMP__
+ PSET_AMP_E,
+ PSET_AMP_P,
+#endif
+} pset_cluster_type_t;
+
+typedef bitmap_t cpumap_t;
projects / apple / xnu.git / blobdiff