Merge all schedule operations to one at the end of interrupt handling.

src/arch/x86_64/interrupt/handler.rs

@@ -25,8 +25,6 @@ use super::TrapFrame;
 
 #[no_mangle]
 pub extern fn rust_trap(tf: &mut TrapFrame) -> usize {
-    let mut rsp = tf as *const _ as usize;
-
     // Dispatch
     match tf.trap_num as u8 {
         T_BRKPT => breakpoint(),
@@ -36,7 +34,7 @@ pub extern fn rust_trap(tf: &mut TrapFrame) -> usize {
         T_IRQ0...64 => {
             let irq = tf.trap_num as u8 - T_IRQ0;
             match irq {
-                IRQ_TIMER => timer(tf, &mut rsp),
+                IRQ_TIMER => timer(),
                 IRQ_KBD => keyboard(),
                 IRQ_COM1 => com1(),
                 IRQ_COM2 => com2(),
@@ -50,11 +48,15 @@ pub extern fn rust_trap(tf: &mut TrapFrame) -> usize {
         }
         T_SWITCH_TOK => to_kernel(tf),
         T_SWITCH_TOU => to_user(tf),
-        T_SYSCALL => syscall(tf, &mut rsp),
-        0x80 => syscall32(tf, &mut rsp),
+        T_SYSCALL => syscall(tf),
+        T_SYSCALL32 => syscall32(tf),
         _ => panic!("Unhandled interrupt {:x}", tf.trap_num),
     }
 
+    let mut rsp = tf as *const _ as usize;
+    use process::PROCESSOR;
+    PROCESSOR.try().unwrap().lock().schedule(&mut rsp);
+
     // Set return rsp if to user
     let tf = unsafe { &*(rsp as *const TrapFrame) };
     set_return_rsp(tf);
@@ -115,9 +117,10 @@ fn com2() {
     COM2.lock().receive();
 }
 
-fn timer(tf: &mut TrapFrame, rsp: &mut usize) {
-    use process;
-    process::timer_handler(tf, rsp);
+fn timer() {
+    use process::PROCESSOR;
+    let mut processor = PROCESSOR.try().unwrap().lock();
+    processor.tick();
 }
 
 fn to_user(tf: &mut TrapFrame) {
@@ -135,17 +138,17 @@ fn to_kernel(tf: &mut TrapFrame) {
     tf.ss = gdt::KDATA_SELECTOR.0 as usize;
 }
 
-fn syscall(tf: &mut TrapFrame, rsp: &mut usize) {
+fn syscall(tf: &mut TrapFrame) {
     info!("\nInterupt: Syscall {:#x?}", tf.rax);
     use syscall::syscall;
-    let ret = syscall(tf, rsp, false);
+    let ret = syscall(tf, false);
     tf.rax = ret as usize;
 }
 
-fn syscall32(tf: &mut TrapFrame, rsp: &mut usize) {
+fn syscall32(tf: &mut TrapFrame) {
     //    info!("\nInterupt: Syscall {:#x?}", tf.rax);
     use syscall::syscall;
-    let ret = syscall(tf, rsp, true);
+    let ret = syscall(tf, true);
     tf.rax = ret as usize;
 }
 

src/process/mod.rs

@@ -36,11 +36,6 @@ extern fn idle_thread() {
     }
 }
 
-pub fn timer_handler(tf: &TrapFrame, rsp: &mut usize) {
-    let mut processor = PROCESSOR.try().unwrap().lock();
-    processor.tick(rsp);
-}
-
 pub fn add_user_process(name: impl AsRef<str>, data: &[u8]) {
     let mut processor = PROCESSOR.try().unwrap().lock();
     let mut mc = MC.try().unwrap().lock();

src/process/processor.rs

@@ -12,6 +12,8 @@ pub struct Processor {
     /// All kernel threads share one page table.
     /// When running user process, it will be stored here.
     kernel_page_table: Option<InactivePageTable>,
+    /// Choose what on next schedule ?
+    next: Option<Pid>,
 }
 
 impl Processor {
@@ -25,9 +27,15 @@ impl Processor {
                 e
             },
             kernel_page_table: None,
+            next: None,
         }
     }
 
+    pub fn set_reschedule(&mut self) {
+        let pid = self.current_pid;
+        self.get_mut(pid).status = Status::Ready;
+    }
+
     fn alloc_pid(&self) -> Pid {
         let mut next: Pid = 0;
         for &i in self.procs.keys() {
@@ -42,18 +50,19 @@ impl Processor {
 
     /// Called by timer.
     /// Handle events.
-    pub fn tick(&mut self, rsp: &mut usize) {
+    pub fn tick(&mut self) {
         self.event_hub.tick();
         while let Some(event) = self.event_hub.pop() {
             debug!("Processor: event {:?}", event);
             match event {
                 Event::Schedule => {
                     self.event_hub.push(10, Event::Schedule);
-                    self.schedule(rsp);
+                    self.set_reschedule();
                 },
                 Event::Wakeup(pid) => {
                     self.get_mut(pid).status = Status::Ready;
-                    self.switch_to(pid, rsp);
+                    self.set_reschedule();
+                    self.next = Some(pid);
                 },
             }
         }
@@ -70,8 +79,13 @@ impl Processor {
         pid
     }
 
+    /// Called every interrupt end
+    /// Do schedule ONLY IF current status != Running
     pub fn schedule(&mut self, rsp: &mut usize) {
-        let pid = self.find_next();
+        if self.current().status == Status::Running {
+            return;
+        }
+        let pid = self.next.take().unwrap_or_else(|| self.find_next());
         self.switch_to(pid, rsp);
     }
 
@@ -84,7 +98,7 @@ impl Processor {
 
     /// Switch process to `pid`, switch page table if necessary.
     /// Store `rsp` and point it to target kernel stack.
-    /// The current status will be set to `Ready` if it is `Running` now.
+    /// The current status must be set before, and not be `Running`.
     fn switch_to(&mut self, pid: Pid, rsp: &mut usize) {
         // for debug print
         let pid0 = self.current_pid;
@@ -98,9 +112,7 @@ impl Processor {
         let (from, to) = self.procs.get_mut2(pid0, pid);
 
         // set `from`
-        if from.status == Status::Running {
-            from.status = Status::Ready;
-        }
+        assert_ne!(from.status, Status::Running);
         from.rsp = *rsp;
 
         // set `to`
@@ -144,7 +156,6 @@ impl Processor {
     }
 
     pub fn exit(&mut self, pid: Pid, error_code: ErrorCode) {
-        assert_ne!(pid, self.current_pid);
         info!("Processor: {} exit, code: {}", pid, error_code);
         self.get_mut(pid).status = Status::Exited(error_code);
         if let Some(waiter) = self.find_waiter(pid) {
@@ -153,8 +164,10 @@ impl Processor {
                 p.status = Status::Ready;
                 p.set_return_value(error_code);
             }
-            info!("Processor: remove {}", pid);
-            self.procs.remove(&pid);
+            // FIXME: remove this process
+            self.get_mut(pid).parent = 0;
+//            info!("Processor: remove {}", pid);
+//            self.procs.remove(&pid);
         }
     }
 

src/syscall.rs

@@ -9,7 +9,7 @@ use util;
 /// 当发生系统调用中断时，中断服务例程将控制权转移到这里。
 /// 它从中断帧中提取参数，根据系统调用号分发执行具体操作。
 /// 它同时支持 xv6的64位程序 和 uCore的32位程序。
-pub fn syscall(tf: &TrapFrame, rsp: &mut usize, is32: bool) -> i32 {
+pub fn syscall(tf: &TrapFrame, is32: bool) -> i32 {
     let id = match is32 {
         false => Syscall::Xv6(tf.rax),
         true => Syscall::Ucore(tf.rax),
@@ -29,19 +29,19 @@ pub fn syscall(tf: &TrapFrame, rsp: &mut usize, is32: bool) -> i32 {
         Syscall::Xv6(SYS_CLOSE) | Syscall::Ucore(UCORE_SYS_CLOSE) =>
             sys_close(args[0]),
         Syscall::Xv6(SYS_WAIT) | Syscall::Ucore(UCORE_SYS_WAIT) =>
-            sys_wait(rsp, args[0], args[1] as *mut i32),
+            sys_wait(args[0], args[1] as *mut i32),
         Syscall::Xv6(SYS_FORK) | Syscall::Ucore(UCORE_SYS_FORK) =>
             sys_fork(tf),
         Syscall::Xv6(SYS_KILL) | Syscall::Ucore(UCORE_SYS_KILL) =>
             sys_kill(args[0]),
         Syscall::Xv6(SYS_EXIT) | Syscall::Ucore(UCORE_SYS_EXIT) =>
-            sys_exit(rsp, args[0]),
+            sys_exit(args[0]),
         Syscall::Ucore(UCORE_SYS_YIELD) =>
-            sys_yield(rsp),
+            sys_yield(),
         Syscall::Ucore(UCORE_SYS_GETPID) =>
             sys_getpid(),
         Syscall::Ucore(UCORE_SYS_SLEEP) =>
-            sys_sleep(rsp, args[0]),
+            sys_sleep(args[0]),
         Syscall::Ucore(UCORE_SYS_GETTIME) =>
             sys_get_time(),
         Syscall::Ucore(UCORE_SYS_PUTC) =>
@@ -92,7 +92,7 @@ fn sys_fork(tf: &TrapFrame) -> i32 {
 
 /// Wait the process exit.
 /// Return the PID. Store exit code to `code` if it's not null.
-fn sys_wait(rsp: &mut usize, pid: usize, code: *mut i32) -> i32 {
+fn sys_wait(pid: usize, code: *mut i32) -> i32 {
     let mut processor = PROCESSOR.try().unwrap().lock();
     let target = match pid {
         0 => WaitTarget::AnyChild,
@@ -105,18 +105,15 @@ fn sys_wait(rsp: &mut usize, pid: usize, code: *mut i32) -> i32 {
             }
             0 // pid as i32
         },
-        WaitResult::Blocked => {
-            processor.schedule(rsp);
-            0 /* unused */
-        },
+        WaitResult::Blocked => 0, // unused
         WaitResult::NotExist => -1,
     }
 }
 
-fn sys_yield(rsp: &mut usize) -> i32 {
+fn sys_yield() -> i32 {
     info!("yield:");
     let mut processor = PROCESSOR.try().unwrap().lock();
-    processor.schedule(rsp);
+    processor.set_reschedule();
     0
 }
 
@@ -132,19 +129,17 @@ fn sys_getpid() -> i32 {
 }
 
 /// Exit the current process
-fn sys_exit(rsp: &mut usize, error_code: usize) -> i32 {
+fn sys_exit(error_code: usize) -> i32 {
     let mut processor = PROCESSOR.try().unwrap().lock();
     let pid = processor.current_pid();
-    processor.schedule(rsp);
     processor.exit(pid, error_code);
     0
 }
 
-fn sys_sleep(rsp: &mut usize, time: usize) -> i32 {
+fn sys_sleep(time: usize) -> i32 {
     info!("sleep: {} ticks", time);
     let mut processor = PROCESSOR.try().unwrap().lock();
     let pid = processor.current_pid();
-    processor.schedule(rsp);
     processor.sleep(pid, time);
     0
 }