kernel: Initial sched rewrite

- Introduce dynamic scheduling policy
- Introduce MLFQ scheduling
- Clean up a lot of code

Signed-off-by: Ian Moffett <ian@osmora.org>

3 files changed, 29 insertions, 2 deletions

diff --git a/sys/include/sys/proc.h b/sys/include/sys/proc.h
index ec7d25e..e3416f9 100644
--- a/sys/include/sys/proc.h
+++ b/sys/include/sys/proc.h
@@ -79,7 +79,9 @@ struct proc {
     struct vm_range addr_range[PROC_MAX_ADDR_RANGE];
     struct spinlock lock;
     uint8_t is_user;
+    uint8_t rested;
     uint32_t signal;
+    uint32_t priority;
     struct filedesc *fds[PROC_MAX_FDS];
     struct spinlock mapspace_lock;
     struct vm_mapspace mapspace;
diff --git a/sys/include/sys/sched.h b/sys/include/sys/sched.h
index 8245120..06cf860 100644
--- a/sys/include/sys/sched.h
+++ b/sys/include/sys/sched.h
@@ -45,9 +45,9 @@ void sched_context_switch(struct trapframe *tf);
 void sched_rest(void);
 
 __noreturn
-uint64_t sys_exit(struct syscall_args *args);
+void sched_enter(void);
 
 __noreturn
-void sched_init_processor(struct cpu_info *ci);
+uint64_t sys_exit(struct syscall_args *args);
 
 #endif  /* !_SYS_SCHED_H_ */
diff --git a/sys/include/sys/schedvar.h b/sys/include/sys/schedvar.h
index 431a93e..2a0a1fc 100644
--- a/sys/include/sys/schedvar.h
+++ b/sys/include/sys/schedvar.h
@@ -30,7 +30,32 @@
 #ifndef _SYS_SCHEDVAR_H_
 #define _SYS_SCHEDVAR_H_
 
+#include <sys/cdefs.h>
+#include <sys/proc.h>
+#include <sys/queue.h>
+
 #define DEFAULT_TIMESLICE_USEC 3000
 #define SHORT_TIMESLICE_USEC 10
 
+#define SCHED_POLICY_MLFQ 0x0000U   /* Multilevel feedback queue */
+#define SCHED_POLICY_RR   0x0001U   /* Round robin */
+
+typedef uint8_t schedpolicy_t;
+
+/* Might be set by kconf(1) */
+#if defined(__SCHED_NQUEUE)
+#define SCHED_NQUEUE __SCHED_NQUEUE
+#else
+#define SCHED_NQUEUE 4
+#endif
+
+/* Ensure SCHED_NQUEUE is an acceptable value */
+__STATIC_ASSERT(SCHED_NQUEUE <= 8, "SCHED_NQUEUE exceeds max");
+__STATIC_ASSERT(SCHED_NQUEUE > 0, "SCHED_NQUEUE cannot be zero");
+
+struct sched_queue {
+    TAILQ_HEAD(, proc) q;
+    size_t nthread;
+};
+
 #endif /* !_SYS_SCHEDVAR_H_ */