helos1/smp/kthread_switch.c
2021-11-08 01:34:06 +08:00

91 lines
2.7 KiB
C

#include "kthread.h"
#include "kthread_switch.h"
#include "internal.h"
#include "../runtime/stdio.h"
#include <string.h>
#include "../util/tree_internal.h"
// defined in assembly
SYSV_ABI void __smp_Switch_Idle();
#define NODE_POINTER(node) (*((__smp_Thread **)(node->data)))
static void printTree(tree_Node *root, int level, __tree_ConnectType type) {
if (!root)
return;
for (int i = 0; i < level * 4; i++)
io_WriteConsoleASCII(" ");
io_Printf("%s, key=%d, data=%llx, &data=%llx\n", type == __tree_Left ? "Left" : "Right", root->key, (uint64_t)NODE_POINTER(root), root->data);
printTree(root->left, level + 1, __tree_Left);
printTree(root->right, level + 1, __tree_Right);
}
SYSV_ABI uintptr_t __smp_Switch() {
// the calling function smp_IntSwitch already CLI-ed for us
// TODO ticker and switch should be 2 functions!
if (!__smp_PauseTicker) {
__smp_Now++;
if (__smp_Now % 8)
return 0;
} else
__smp_PauseTicker = false;
//io_Printf("__smp_Switch: Tick: %d, switching\n", __smp_Now);
__smp_Thread *t = __smp_Current[0];
tree_Node *node = 0;
// insert the current thread back into the waiting queue
if (t) {
uint64_t priority = t->nice + (t->lastTick > __smp_Now ? t->lastTick : __smp_Now); // new priority for the thread
bool ok = false;
do {
node = tree_InsertNode(__smp_ThreadsWaiting, priority, &ok);
priority++;
} while (!ok);
NODE_POINTER(node) = t;
}
//printTree(__smp_Threads->root, 0, 0);
//printTree(__smp_ThreadsWaiting->root, 0, 0);
tree_Node *first = tree_FirstNode(__smp_ThreadsWaiting);
//io_Printf(" first0.id=%d\n", NODE_POINTER(first) ? NODE_POINTER(first)->id : 0);
while (first && NODE_POINTER(first)->lastTick > __smp_Now) {
//io_Printf(" iterating, .id=%d\n", NODE_POINTER(first) ? NODE_POINTER(first)->id : 0);
first = tree_Node_Next(first);
}
if (first == node) {
// the current thread is still the first, return
//io_Printf(" Not context switching, still running %d\n", t ? t->id : 0);
if (node)
tree_Delete(__smp_ThreadsWaiting, node);
return 0;
}
// we need a real context switch
// first save the current thread context
t->lastTick = __smp_Now;
memcpy(&t->state, &__smp_IntSwitch_LastState, sizeof(smp_thread_State));
if (!first) {
// no thread available, load a dummy idle thread
__smp_IntSwitch_LastState.rip = (uint64_t)__smp_Switch_Idle;
__smp_Current[0] = 0;
io_WriteConsoleASCII("__smp_Switch: Entering idle\n");
} else {
// load the new context
io_Printf(" Context switching, from %d to %d\n", t ? t->id : 0, NODE_POINTER(first)->id);
memcpy(&__smp_IntSwitch_LastState, &NODE_POINTER(first)->state, sizeof(smp_thread_State));
__smp_Current[0] = NODE_POINTER(first);
tree_Delete(__smp_ThreadsWaiting, first);
}
return 1;
}