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smp: properly recycle thread stack frames

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Edgaru089 2021-11-11 16:02:09 +08:00
parent 20bc9f4a64
commit c0c2c12493
3 changed files with 20 additions and 4 deletions
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1
smp/internal.c
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@ -12,3 +12,4 @@ smp_thread_ID __smp_Idallo;
tree_Tree *__smp_Threads;
tree_Tree *__smp_ThreadsWaiting;
tree_Tree *__smp_StackPool;

4
smp/internal.h
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@ -22,6 +22,7 @@ typedef struct {
// Last-saved thread state after preemptive context switch
smp_thread_State state;
uint64_t stackframe; // stack frame, lowest (begin) addr
} __smp_Thread;
// variables defined in internal.c
@ -48,3 +49,6 @@ extern smp_thread_ID __smp_Idallo;
extern tree_Tree *__smp_Threads;
// [priority] -> struct __smp_Thread*
extern tree_Tree *__smp_ThreadsWaiting;
// unused thread stack pages for use; 4K in size
extern tree_Tree *__smp_StackPool;

19
smp/kthread.c
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@ -21,6 +21,9 @@ SYSV_ABI NORETURN void __smp_thread_Cleanup() {
tree_Delete(__smp_Threads, tree_FindNode(__smp_Threads, t->id));
__smp_Current[0] = 0;
// Push the freed stack frame into the pool
tree_Insert(__smp_StackPool, t->stackframe, NULL);
// Now that we're pretending to be a idle thread, this should not return
// thread_Switch() sets the interrupt flag on idle for us
smp_thread_Yield();
@ -32,6 +35,7 @@ smp_thread_ID smp_thread_Init() {
INTERRUPT_DISABLE;
__smp_Threads = tree_Create(sizeof(__smp_Thread));
__smp_ThreadsWaiting = tree_Create(sizeof(void *));
__smp_StackPool = tree_Create(0);
__smp_Now = 1;
smp_thread_ID id = ++__smp_Idallo;
@ -79,10 +83,17 @@ smp_thread_ID smp_thread_Start(void *entry, const smp_thread_Arguments *args, un
t->state.r8 = args->e;
t->state.r9 = args->f;
// allocate a new 4K stack
uint64_t newstack = memory_AllocateKernelMapping(4096, 4096);
paging_map_PageAllocated(newstack, 1, MAP_PROT_READ | MAP_PROT_WRITE);
t->state.rsp = newstack + 4096;
tree_Node *spare = tree_FirstNode(__smp_StackPool);
if (spare) {
// use the existing stack from the pool
t->state.rsp = t->stackframe = spare->key + 4096;
tree_Delete(__smp_StackPool, spare);
} else {
// allocate a new 4K stack
uint64_t newstack = memory_AllocateKernelMapping(4096, 4096);
paging_map_PageAllocated(newstack, 1, MAP_PROT_READ | MAP_PROT_WRITE);
t->state.rsp = t->stackframe = newstack + 4096;
}
// insert the thread into the waiting queue
*((void **)tree_Insert(__smp_ThreadsWaiting, t->lastTick + t->nice, 0)) = t;