From de003ed64cdab6f9b37db954a81a189896c77c62 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E5=88=98=E4=B8=B0=E6=BA=90?=
 <liufy17@mails.tsinghua.edu.cn>
Date: Tue, 28 Jul 2020 18:37:22 +0800
Subject: [PATCH] remove exit thread from THREADS

---
 kernel/src/process/proc.rs   |  8 ++++++++
 kernel/src/process/thread.rs | 24 ++++++++++++++++++++----
 kernel/src/syscall/proc.rs   |  1 +
 3 files changed, 29 insertions(+), 4 deletions(-)

diff --git a/kernel/src/process/proc.rs b/kernel/src/process/proc.rs
index dc1bfce4..930c6ede 100644
--- a/kernel/src/process/proc.rs
+++ b/kernel/src/process/proc.rs
@@ -106,6 +106,10 @@ pub struct Process {
     /// threads in the same process
     pub threads: Vec<Tid>,
 
+    /// Threads
+    /// threads in the same process, witch has exit, wait release
+    pub exit_threads: Vec<Tid>,
+
     /// Events like exiting
     pub eventbus: Arc<Mutex<EventBus>>,
 
@@ -217,7 +221,11 @@ impl Process {
         for tid in self.threads.iter() {
             thread_table.remove(tid);
         }
+        for tid in self.exit_threads.iter() {
+            thread_table.remove(tid);
+        }
         self.threads.clear();
+        self.exit_threads.clear();
 
         info!("process {} exit with {}", self.pid.get(), exit_code);
     }
diff --git a/kernel/src/process/thread.rs b/kernel/src/process/thread.rs
index 3891aae2..2a6c20a9 100644
--- a/kernel/src/process/thread.rs
+++ b/kernel/src/process/thread.rs
@@ -93,15 +93,29 @@ lazy_static! {
         RwLock::new(BTreeMap::new());
 }
 
+/// next thread's id
+pub static ALLOC_ID: Mutex<usize> = Mutex::new(1);
+
+fn alloc_tid() -> Tid {
+    // let tid = (Pid::INIT..)
+    //     .find(|i| thread_table.get(i).is_none())
+    //     .unwrap();
+    let mut w = ALLOC_ID.lock();
+    let tid = *w;
+    *w += 1;
+    if *w > 1000 {
+        *w = 1;
+    }
+    tid
+}
+
 impl Thread {
     /// Assign a tid and put itself to global thread table.
     pub fn add_to_table(mut self) -> Arc<Self> {
         let mut thread_table = THREADS.write();
 
         // assign tid, do not start from 0
-        let tid = (Pid::INIT..)
-            .find(|i| thread_table.get(i).is_none())
-            .unwrap();
+        let tid = alloc_tid();
         self.tid = tid;
 
         // put to thread table
@@ -343,6 +357,7 @@ impl Thread {
                 parent: (Pid::new(), Weak::new()),
                 children: Vec::new(),
                 threads: Vec::new(),
+                exit_threads: Vec::new(),
                 exit_code: 0,
                 pending_sigset: Sigset::empty(),
                 sig_queue: VecDeque::new(),
@@ -386,6 +401,7 @@ impl Thread {
             parent: (proc.pid.clone(), Arc::downgrade(&self.proc)),
             children: Vec::new(),
             threads: Vec::new(),
+            exit_threads: Vec::new(),
             exit_code: 0,
             pending_sigset: Sigset::empty(),
             sig_queue: VecDeque::new(),
@@ -516,7 +532,7 @@ pub fn spawn(thread: Arc<Thread>) {
                 _ if is_page_fault(trap_num) => {
                     // page fault
                     let addr = get_page_fault_addr();
-                    info!("page fault from user @ {:#x}", addr);
+                    // info!("page fault from user @ {:#x}", addr);
 
                     if !handle_user_page_fault(&thread, addr) {
                         // TODO: SIGSEGV
diff --git a/kernel/src/syscall/proc.rs b/kernel/src/syscall/proc.rs
index ddb7feed..429f73ad 100644
--- a/kernel/src/syscall/proc.rs
+++ b/kernel/src/syscall/proc.rs
@@ -342,6 +342,7 @@ impl Syscall<'_> {
 
         let mut proc = self.process();
         proc.threads.retain(|&id| id != tid);
+        proc.exit_threads.push(tid);
 
         // for last thread, exit the process
         if proc.threads.len() == 0 {