kernel/CMakeLists.txt

@@ -25,7 +25,6 @@ set(SOURCES
     src/thread/Thread.cpp
     src/thread/ThreadImage.cpp
     src/thread/Scheduler.cpp
-    src/thread/Timer.cpp
     src/sys/Syscall.cpp
     src/sys/exit.cpp
     src/sys/clock_gettime.cpp

kernel/src/sys/alarm.cpp

@@ -1,7 +1,6 @@
 #include "Pledge.h"
 #include "sys/Syscall.h"
 #include "thread/Scheduler.h"
-#include "thread/Timer.h"
 
 Result<u64> sys_alarm(Registers*, SyscallArgs args)
 {
@@ -11,16 +10,9 @@ Result<u64> sys_alarm(Registers*, SyscallArgs args)
 
     TRY(check_pledge(current, Promise::p_stdio));
 
-    u64 ticks_left = current->timer ? current->timer->ticks_left() : 0;
+    u64 time_left = current->alarm_ticks_left;
 
-    if (current->timer) Scheduler::remove_from_timer_queue(current->timer);
-    else
-        current->timer = TRY(make<Scheduler::Timer>());
+    current->alarm_ticks_left = seconds * 1000;
 
-    current->timer->total_ticks = seconds * 1000;
-    current->timer->thread = current;
-
-    Scheduler::add_to_timer_queue(current->timer);
-
-    return ticks_left * 1000;
+    return time_left * 1000;
 }

kernel/src/thread/Scheduler.cpp

@@ -5,7 +5,6 @@
 #include "binfmt/ELF.h"
 #include "memory/MemoryManager.h"
 #include "thread/ThreadImage.h"
-#include "thread/Timer.h"
 #include <luna/Alignment.h>
 #include <luna/ScopeGuard.h>
 #include <luna/Stack.h>
@@ -217,12 +216,6 @@ namespace Scheduler
             MemoryManager::unmap_owned_and_free_vm(stack.bottom(), stack.bytes() / ARCH_PAGE_SIZE).release_value();
         }
 
-        if (thread->timer)
-        {
-            Scheduler::remove_from_timer_queue(thread->timer);
-            delete thread->timer;
-        }
-
         delete thread;
 
         CPU::enable_interrupts();
@@ -300,8 +293,6 @@ namespace Scheduler
     {
         CPU::disable_interrupts();
 
-        tick_queue();
-
         if (is_in_kernel(regs)) g_current->kernel_ticks_self++;
         else
             g_current->user_ticks_self++;
@@ -314,6 +305,8 @@ namespace Scheduler
             {
                 if (thread->sleep_ticks_left == 0 || --thread->sleep_ticks_left == 0) thread->wake_up();
             }
+
+            if (thread->alarm_ticks_left && --thread->alarm_ticks_left == 0) thread->send_signal(SIGALRM);
         }
 
         if (!g_current->ticks_left) switch_task(regs);

kernel/src/thread/Thread.h

@@ -19,11 +19,6 @@
 #error "Unknown architecture."
 #endif
 
-namespace Scheduler
-{
-    class Timer;
-}
-
 enum class ThreadState
 {
     None,
@@ -65,6 +60,7 @@ struct Thread : public LinkedListNode<Thread>
 
     u64 ticks_left;
     u64 sleep_ticks_left;
+    u64 alarm_ticks_left { 0 };
 
     int promises { -1 };
     int execpromises { -1 };
@@ -101,8 +97,6 @@ struct Thread : public LinkedListNode<Thread>
 
     mode_t umask { 0 };
 
-    Scheduler::Timer* timer { nullptr };
-
     StaticString<128> cmdline;
 
     String current_directory_path = {};

kernel/src/thread/Timer.cpp

@@ -1,72 +0,0 @@
-#include "thread/Timer.h"
-#include "Log.h"
-
-static LinkedList<Scheduler::Timer> g_timer_queue;
-
-namespace Scheduler
-{
-    void add_to_timer_queue(Timer* timer)
-    {
-        timer->delta_ticks = timer->total_ticks;
-
-        for (auto* t : g_timer_queue)
-        {
-            if (timer->delta_ticks <= t->delta_ticks)
-            {
-                t->delta_ticks -= timer->delta_ticks;
-                g_timer_queue.add_before(t, timer);
-                return;
-            }
-            timer->delta_ticks -= t->delta_ticks;
-        }
-
-        g_timer_queue.append(timer);
-    }
-
-    void remove_from_timer_queue(Timer* timer)
-    {
-        auto maybe_next = g_timer_queue.next(timer);
-        if (maybe_next.has_value())
-        {
-            auto next = maybe_next.value();
-            next->delta_ticks += timer->delta_ticks;
-        }
-        g_timer_queue.remove(timer);
-    }
-
-    void tick_queue()
-    {
-        auto maybe_first = g_timer_queue.first();
-        if (!maybe_first.has_value()) return;
-
-        auto first = *maybe_first;
-        first->delta_ticks--;
-
-        LinkedList<Scheduler::Timer> timers_to_be_restarted;
-
-        g_timer_queue.delayed_for_each([&](Timer* t) {
-            if (t->delta_ticks == 0)
-            {
-                g_timer_queue.remove(t);
-                t->thread->send_signal(t->signo);
-                if (t->restart) timers_to_be_restarted.append(t);
-                return true;
-            }
-
-            return false;
-        });
-
-        timers_to_be_restarted.consume([](Timer* t) { add_to_timer_queue(t); });
-    }
-
-    u64 Timer::ticks_left()
-    {
-        u64 total = 0;
-        for (auto* t : g_timer_queue)
-        {
-            total += t->delta_ticks;
-            if (t == this) break;
-        }
-        return total;
-    }
-}

kernel/src/thread/Timer.h

@@ -1,23 +0,0 @@
-#pragma once
-#include "thread/Thread.h"
-#include <luna/LinkedList.h>
-
-namespace Scheduler
-{
-    class Timer : public LinkedListNode<Timer>
-    {
-      public:
-        u64 delta_ticks;
-        u64 total_ticks;
-        Thread* thread;
-        int signo { SIGALRM };
-        bool restart { false };
-
-        u64 ticks_left();
-    };
-
-    void add_to_timer_queue(Timer* timer);
-    void remove_from_timer_queue(Timer* timer);
-
-    void tick_queue();
-}

libluna/include/luna/LinkedList.h

@@ -108,22 +108,6 @@ template <typename T> class LinkedList
         m_count++;
     }
 
-    void add_before(T* base, T* ptr)
-    {
-        Node* const new_node = extract_node(ptr);
-        Node* const base_node = extract_node(base);
-
-        if (m_start_node == base_node) m_start_node = new_node;
-
-        if (base_node->get_last()) base_node->get_last()->set_next(new_node);
-
-        new_node->set_last(base_node->get_last());
-        base_node->set_last(new_node);
-        new_node->set_next(base_node);
-
-        m_count++;
-    }
-
     T* remove(T* ptr)
     {
         Node* const node = extract_node(ptr);