void
rust_task::new_stack(size_t requested_sz) {
LOG(this, mem, "creating new stack for task %" PRIxPTR, this);
if (stk) {
::check_stack_canary(stk);
}
// The minimum stack size, in bytes, of a Rust stack, excluding red zone
size_t min_sz = thread->min_stack_size;
// Try to reuse an existing stack segment
while (stk != NULL && stk->next != NULL) {
size_t next_sz = user_stack_size(stk->next);
if (min_sz <= next_sz && requested_sz <= next_sz) {
LOG(this, mem, "reusing existing stack");
stk = stk->next;
return;
} else {
LOG(this, mem, "existing stack is not big enough");
stk_seg *new_next = stk->next->next;
free_stack(stk->next);
stk->next = new_next;
if (new_next) {
new_next->prev = stk;
}
}
}
// The size of the current stack segment, excluding red zone
size_t current_sz = 0;
if (stk != NULL) {
current_sz = user_stack_size(stk);
}
// The calculated size of the new stack, excluding red zone
size_t rust_stk_sz = get_next_stack_size(min_sz,
current_sz, requested_sz);
if (total_stack_sz + rust_stk_sz > thread->env->max_stack_size) {
LOG_ERR(this, task, "task %" PRIxPTR " ran out of stack", this);
fail();
}
size_t sz = rust_stk_sz + RED_ZONE_SIZE;
stk_seg *new_stk = create_stack(&local_region, sz);
LOGPTR(thread, "new stk", (uintptr_t)new_stk);
new_stk->task = this;
new_stk->next = NULL;
new_stk->prev = stk;
if (stk) {
stk->next = new_stk;
}
LOGPTR(thread, "stk end", new_stk->end);
stk = new_stk;
total_stack_sz += user_stack_size(new_stk);
}
void
rust_task::new_stack(size_t requested_sz) {
LOG(this, mem, "creating new stack for task %" PRIxPTR, this);
if (stk) {
::check_stack_canary(stk);
}
// The minimum stack size, in bytes, of a Rust stack, excluding red zone
size_t min_sz = sched_loop->min_stack_size;
// Try to reuse an existing stack segment
while (stk != NULL && stk->next != NULL) {
size_t next_sz = user_stack_size(stk->next);
if (min_sz <= next_sz && requested_sz <= next_sz) {
LOG(this, mem, "reusing existing stack");
stk = stk->next;
return;
} else {
LOG(this, mem, "existing stack is not big enough");
stk_seg *new_next = stk->next->next;
free_stack(stk->next);
stk->next = new_next;
if (new_next) {
new_next->prev = stk;
}
}
}
// The size of the current stack segment, excluding red zone
size_t current_sz = 0;
if (stk != NULL) {
current_sz = user_stack_size(stk);
}
// The calculated size of the new stack, excluding red zone
size_t rust_stk_sz = get_next_stack_size(min_sz,
current_sz, requested_sz);
size_t max_stack = kernel->env->max_stack_size;
size_t used_stack = total_stack_sz + rust_stk_sz;
// Don't allow stacks to grow forever. During unwinding we have to allow
// for more stack than normal in order to allow destructors room to run,
// arbitrarily selected as 2x the maximum stack size.
if (!unwinding && used_stack > max_stack) {
LOG_ERR(this, task, "task %" PRIxPTR " ran out of stack", this);
abort();
} else if (unwinding && used_stack > max_stack * 2) {
LOG_ERR(this, task,
"task %" PRIxPTR " ran out of stack during unwinding", this);
abort();
}
size_t sz = rust_stk_sz + RED_ZONE_SIZE;
stk_seg *new_stk = create_stack(&local_region, sz);
LOGPTR(sched_loop, "new stk", (uintptr_t)new_stk);
new_stk->task = this;
new_stk->next = NULL;
new_stk->prev = stk;
if (stk) {
stk->next = new_stk;
}
LOGPTR(sched_loop, "stk end", new_stk->end);
stk = new_stk;
total_stack_sz += user_stack_size(new_stk);
}
void
rust_task::free_stack(stk_seg *stk) {
LOGPTR(sched_loop, "freeing stk segment", (uintptr_t)stk);
total_stack_sz -= user_stack_size(stk);
destroy_stack(&local_region, stk);
}