예제 #1
0
/**
 * determine_dirtyable_memory - amount of memory that may be used
 *
 * Returns the numebr of pages that can currently be freed and used
 * by the kernel for direct mappings.
 */
unsigned long determine_dirtyable_memory(void)
{
	unsigned long x;

	x = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages();

	if (!vm_highmem_is_dirtyable)
		x -= highmem_dirtyable_memory(x);

	return x + 1;	/* Ensure that we never return 0 */
}
static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc)
{
	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) -
						global_page_state(NR_SHMEM);
	struct zone *zone;
#ifdef CONFIG_LGE_ANDROID_LOW_MEMORY_KILLER_PATCH
	/*
	 * to avoid too many oom-killer, check reclaimable page condition
	 * Although lowmemorykiller got killed apks or selected adj well under the given condition, oom-killer is followed by sometime.
	 */
	int reclaimable_pages = global_reclaimable_pages();
#endif

	if (offlining) {
		/* Discount all free space in the section being offlined */
		for_each_zone(zone) {
			 if (zone_idx(zone) == ZONE_MOVABLE) {
				other_free -= zone_page_state(zone,
						NR_FREE_PAGES);
				lowmem_print(4, "lowmem_shrink discounted "
					"%lu pages in movable zone\n",
					zone_page_state(zone, NR_FREE_PAGES));
			}
		}
	}
	/*
	 * 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 &&
	    time_before_eq(jiffies, lowmem_deathpending_timeout))
		return 0;

	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++) {
#ifdef CONFIG_LGE_ANDROID_LOW_MEMORY_KILLER_PATCH
		if (((other_free < lowmem_minfree[i]) && (other_file < lowmem_minfree[i])) 
			||((other_free < lowmem_minfree[i]) && (reclaimable_pages < lowmem_minfree[i]))){
			min_adj = lowmem_adj[i];
			break;
		}
#else
		if (other_free < lowmem_minfree[i] &&
		    other_file < lowmem_minfree[i]) {
			min_adj = lowmem_adj[i];
			break;
		}
#endif	
	}
	if (sc->nr_to_scan > 0)
		lowmem_print(3, "lowmem_shrink %lu, %x, ofree %d %d, ma %d\n",
			     sc->nr_to_scan, sc->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 (sc->nr_to_scan <= 0 || min_adj == OOM_ADJUST_MAX + 1) {
		lowmem_print(5, "lowmem_shrink %lu, %x, return %d\n",
			     sc->nr_to_scan, sc->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;

		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);
		lowmem_deathpending = selected;
		lowmem_deathpending_timeout = jiffies + HZ;
		force_sig(SIGKILL, selected);
		rem -= selected_tasksize;
	}
	lowmem_print(4, "lowmem_shrink %lu, %x, return %d\n",
		     sc->nr_to_scan, sc->gfp_mask, rem);
	read_unlock(&tasklist_lock);
	return rem;
}