コード例 #1
0
static void __exit lowmem_exit(void)
{
	unregister_shrinker(&lowmem_shrinker);
	task_free_unregister(&task_nb);
}
コード例 #2
0
static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask)
{
	struct task_struct *p;
	struct task_struct *selected = NULL;
	int rem = 0;
	int tasksize;
	int i;
	int min_adj = OOM_ADJUST_MAX + 1;
	int selected_tasksize = 0;
	int selected_oom_adj;
	int array_size = ARRAY_SIZE(lowmem_adj);
	int other_free = global_page_state(NR_FREE_PAGES);
	int other_file = global_page_state(NR_FILE_PAGES);
	int lru_file = global_page_state(NR_ACTIVE_FILE) +
			global_page_state(NR_INACTIVE_FILE);

	/*
	 * If we already have a death outstanding, then
	 * bail out right away; indicating to vmscan
	 * that we have nothing further to offer on
	 * this pass.
	 *
	 */
	if (lowmem_deathpending) {
		dump_deathpending(lowmem_deathpending);
		if (lowmem_deathpending_retries++ < lowmem_max_deathpending_retries)
			return 0;
		else
			task_free_unregister(&task_nb);
	}

	if (lowmem_adj_size < array_size)
		array_size = lowmem_adj_size;
	if (lowmem_minfree_size < array_size)
		array_size = lowmem_minfree_size;
	for (i = 0; i < array_size; i++) {
		if (other_free < lowmem_minfree[i]) {
			if(other_file < lowmem_minfree[i] ||
				(lowmem_check_filepages &&
				(lru_file < lowmem_minfile[i]))) {

				min_adj = lowmem_adj[i];
				break;
			}
		}
	}
	if (nr_to_scan > 0)
		lowmem_print(3, "lowmem_shrink %d, %x, ofree %d %d, ma %d\n",
			     nr_to_scan, gfp_mask, other_free, other_file,
			     min_adj);
	rem = global_page_state(NR_ACTIVE_ANON) +
		global_page_state(NR_ACTIVE_FILE) +
		global_page_state(NR_INACTIVE_ANON) +
		global_page_state(NR_INACTIVE_FILE);
	if (nr_to_scan <= 0 || min_adj == OOM_ADJUST_MAX + 1) {
		lowmem_print(5, "lowmem_shrink %d, %x, return %d\n",
			     nr_to_scan, gfp_mask, rem);
		return rem;
	}
	selected_oom_adj = min_adj;

	read_lock(&tasklist_lock);
	for_each_process(p) {
		struct mm_struct *mm;
		struct signal_struct *sig;
		int oom_adj;

		if (p == lowmem_deathpending) {
			lowmem_print(2, "skip death pending task %d (%s)\n",
							p->pid, p->comm);
			continue;
		}

		task_lock(p);
		mm = p->mm;
		sig = p->signal;
		if (!mm || !sig) {
			task_unlock(p);
			continue;
		}
		oom_adj = sig->oom_adj;
		if (oom_adj < min_adj) {
			task_unlock(p);
			continue;
		}
		tasksize = get_mm_rss(mm);
		task_unlock(p);
		if (tasksize <= 0)
			continue;
		if (selected) {
			if (oom_adj < selected_oom_adj)
				continue;
			if (oom_adj == selected_oom_adj &&
			    tasksize <= selected_tasksize)
				continue;
		}
		selected = p;
		selected_tasksize = tasksize;
		selected_oom_adj = oom_adj;
		lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",
			     p->pid, p->comm, oom_adj, tasksize);
	}
	if (selected) {
		lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",
			     selected->pid, selected->comm,
			     selected_oom_adj, selected_tasksize);
		if (!ignore_lowmem_deathpending) {
			lowmem_deathpending = selected;
			lowmem_deathpending_retries = 0;
			task_free_register(&task_nb);
		}
		force_sig(SIGKILL, selected);
		rem -= selected_tasksize;
	}
	else {
		lowmem_deathpending = NULL;
	}

	lowmem_print(4, "lowmem_shrink %d, %x, return %d\n",
		     nr_to_scan, gfp_mask, rem);
	read_unlock(&tasklist_lock);
	return rem;
}