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Initial priority-based scheduler

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- Scheduler now has multiple linked_lists of processes at different
  priorities
- Process structure improvements
- scheduler::tick() and scheduler::schedule() separation
This commit is contained in:
Justin C. Miller
2018-09-11 22:37:00 -07:00
parent 593cda3ee8
commit fafe582802
7 changed files with 136 additions and 23 deletions
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76
src/kernel/scheduler.cpp
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@@ -20,20 +20,33 @@ const uint64_t rflags_int = 0x202;
extern "C" {
void ramdisk_process_loader();
void load_process(const void *image_start, size_t butes, cpu_state state);
void load_process(const void *image_start, size_t bytes, process *proc, cpu_state state);
};
scheduler::scheduler(lapic *apic) :
m_apic(apic),
m_current(0),
m_next_pid(0)
m_next_pid(1)
{
m_processes.ensure_capacity(50);
m_processes.append({m_next_pid++, 0, page_manager::get_pml4()}); // The kernel idle task, also the thread we're in now
auto *idle = m_process_allocator.pop();
uint8_t last_pri = num_priorities - 1;
// The kernel idle task, also the thread we're in now
idle->pid = 0;
idle->ppid = 0;
idle->priority = last_pri;
idle->rsp = 0; // This will get set when we switch away
idle->pml4 = page_manager::get_pml4();
idle->flags =
process_flags::ready |
process_flags::const_pri;
m_runlists[last_pri].push_back(idle);
m_current = idle;
}
void
load_process(const void *image_start, size_t bytes, cpu_state state)
load_process(const void *image_start, size_t bytes, process *proc, cpu_state state)
{
// We're now in the process space for this process, allocate memory for the
// process code and load it
@@ -85,6 +98,7 @@ load_process(const void *image_start, size_t bytes, cpu_state state)
}
state.rip = image.entrypoint();
proc->flags &= ~process_flags::loading;
log::debug(logs::task, "Loaded! New process state:");
log::debug(logs::task, " CS: %d [%d]", state.cs >> 3, state.cs & 0x07);
@@ -137,14 +151,28 @@ scheduler::create_process(const char *name, const void *data, size_t size)
loader_state->rbx = size;
uint16_t pid = m_next_pid++;
auto *proc = m_process_allocator.pop();
proc->pid = pid;
proc->ppid = 0; // TODO
proc->priority = default_priority;
proc->rsp = reinterpret_cast<addr_t>(loader_state);
proc->pml4 = pml4;
proc->flags =
process_flags::ready |
process_flags::loading;
m_runlists[default_priority].push_back(proc);
loader_state->rcx = reinterpret_cast<uint64_t>(proc);
log::debug(logs::task, "Creating process %s:", name);
log::debug(logs::task, " PID %d", pid);
log::debug(logs::task, " Pri %d", pid);
log::debug(logs::task, " RSP0 %016lx", state);
log::debug(logs::task, " RSP3 %016lx", state->user_rsp);
log::debug(logs::task, " PML4 %016lx", pml4);
log::debug(logs::task, " Loading %016lx [%d]", loader_state->rax, loader_state->rbx);
m_processes.append({pid, reinterpret_cast<addr_t>(loader_state), pml4});
}
void
@@ -155,21 +183,41 @@ scheduler::start()
}
addr_t
scheduler::tick(addr_t rsp0)
scheduler::schedule(addr_t rsp0)
{
log::debug(logs::task, "Scheduler tick.");
m_current->rsp = rsp0;
m_runlists[m_current->priority].remove(m_current);
m_runlists[m_current->priority].push_back(m_current);
m_processes[m_current].rsp = rsp0;
m_current = (m_current + 1) % m_processes.count();
rsp0 = m_processes[m_current].rsp;
uint8_t pri = 0;
while (m_runlists[pri].empty()) {
++pri;
kassert(pri < num_priorities, "All runlists are empty");
}
m_current = m_runlists[pri].pop_front();
rsp0 = m_current->rsp;
// Set rsp0 to after the end of the about-to-be-popped cpu state
tss_set_stack(0, rsp0 + sizeof(cpu_state));
// Swap page tables
page_table *pml4 = m_processes[m_current].pml4;
page_table *pml4 = m_current->pml4;
page_manager::set_pml4(pml4);
bool loading = bitfield_has(m_current->flags, process_flags::loading);
log::debug(logs::task, "Scheduler switched to process %d, priority %d%s.",
m_current->pid, m_current->priority, loading ? " (loading)" : "");
return rsp0;
}
addr_t
scheduler::tick(addr_t rsp0)
{
// TODO: action based on the task using the whole quantum
rsp0 = schedule(rsp0);
m_apic->reset_timer(quantum);
return rsp0;
}