[deliverable/linux.git] / drivers / staging / android / lowmemorykiller.c

/* drivers/misc/lowmemorykiller.c
 *
 * Copyright (C) 2007-2008 Google, Inc.
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/oom.h>
#include <linux/sched.h>

static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask);

static struct shrinker lowmem_shrinker = {
	.shrink = lowmem_shrink,
	.seeks = DEFAULT_SEEKS * 16
};
static uint32_t lowmem_debug_level = 2;
static int lowmem_adj[6] = {
	0,
	1,
	6,
	12,
};
static int lowmem_adj_size = 4;
static size_t lowmem_minfree[6] = {
	3*512, // 6MB
	2*1024, // 8MB
	4*1024, // 16MB
	16*1024, // 64MB
};
static int lowmem_minfree_size = 4;

#define lowmem_print(level, x...) do { if(lowmem_debug_level >= (level)) printk(x); } while(0)

module_param_named(cost, lowmem_shrinker.seeks, int, S_IRUGO | S_IWUSR);
module_param_array_named(adj, lowmem_adj, int, &lowmem_adj_size, S_IRUGO | S_IWUSR);
module_param_array_named(minfree, lowmem_minfree, uint, &lowmem_minfree_size, S_IRUGO | S_IWUSR);
module_param_named(debug_level, lowmem_debug_level, uint, S_IRUGO | S_IWUSR);

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);

	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] &&
		    other_file < lowmem_minfree[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) {
		int oom_adj;

		task_lock(p);
		if (!p->mm) {
			task_unlock(p);
			continue;
		}
		oom_adj = p->oomkilladj;
		if (oom_adj < min_adj) {
			task_unlock(p);
			continue;
		}
		tasksize = get_mm_rss(p->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);
		force_sig(SIGKILL, selected);
		rem -= selected_tasksize;
	}
	lowmem_print(4, "lowmem_shrink %d, %x, return %d\n",
		     nr_to_scan, gfp_mask, rem);
	read_unlock(&tasklist_lock);
	return rem;
}

static int __init lowmem_init(void)
{
	register_shrinker(&lowmem_shrinker);
	return 0;
}

static void __exit lowmem_exit(void)
{
	unregister_shrinker(&lowmem_shrinker);
}

module_init(lowmem_init);
module_exit(lowmem_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
08b88cc7 SM	1	/* drivers/misc/lowmemorykiller.c
	2	*
	3	* Copyright (C) 2007-2008 Google, Inc.
	4	*
	5	* This software is licensed under the terms of the GNU General Public
	6	* License version 2, as published by the Free Software Foundation, and
	7	* may be copied, distributed, and modified under those terms.
	8	*
	9	* This program is distributed in the hope that it will be useful,
	10	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	11	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	12	* GNU General Public License for more details.
	13	*
	14	*/
	15
	16	#include <linux/module.h>
	17	#include <linux/kernel.h>
	18	#include <linux/mm.h>
	19	#include <linux/oom.h>
	20	#include <linux/sched.h>
	21
	22	static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask);
	23
	24	static struct shrinker lowmem_shrinker = {
	25	.shrink = lowmem_shrink,
	26	.seeks = DEFAULT_SEEKS * 16
	27	};
	28	static uint32_t lowmem_debug_level = 2;
	29	static int lowmem_adj[6] = {
	30	0,
	31	1,
	32	6,
	33	12,
	34	};
	35	static int lowmem_adj_size = 4;
	36	static size_t lowmem_minfree[6] = {
	37	3*512, // 6MB
	38	2*1024, // 8MB
	39	4*1024, // 16MB
	40	16*1024, // 64MB
	41	};
	42	static int lowmem_minfree_size = 4;
	43
	44	#define lowmem_print(level, x...) do { if(lowmem_debug_level >= (level)) printk(x); } while(0)
	45
	46	module_param_named(cost, lowmem_shrinker.seeks, int, S_IRUGO \| S_IWUSR);
	47	module_param_array_named(adj, lowmem_adj, int, &lowmem_adj_size, S_IRUGO \| S_IWUSR);
	48	module_param_array_named(minfree, lowmem_minfree, uint, &lowmem_minfree_size, S_IRUGO \| S_IWUSR);
	49	module_param_named(debug_level, lowmem_debug_level, uint, S_IRUGO \| S_IWUSR);
	50
	51	static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask)
	52	{
	53	struct task_struct *p;
	54	struct task_struct *selected = NULL;
	55	int rem = 0;
	56	int tasksize;
	57	int i;
	58	int min_adj = OOM_ADJUST_MAX + 1;
	59	int selected_tasksize = 0;
34006e11	60	int selected_oom_adj;
08b88cc7	61	int array_size = ARRAY_SIZE(lowmem_adj);
31d59a41 AH	62	int other_free = global_page_state(NR_FREE_PAGES);
31d59a41 AH	63	int other_file = global_page_state(NR_FILE_PAGES);
34006e11 DR	64
34006e11 DR	65	if (lowmem_adj_size < array_size)
08b88cc7	66	array_size = lowmem_adj_size;
34006e11	67	if (lowmem_minfree_size < array_size)
08b88cc7	68	array_size = lowmem_minfree_size;
34006e11	69	for (i = 0; i < array_size; i++) {
31d59a41 AH	70	if (other_free < lowmem_minfree[i] &&
31d59a41 AH	71	other_file < lowmem_minfree[i]) {
08b88cc7 SM	72	min_adj = lowmem_adj[i];
	73	break;
	74	}
	75	}
34006e11 DR	76	if (nr_to_scan > 0)
	77	lowmem_print(3, "lowmem_shrink %d, %x, ofree %d %d, ma %d\n",
	78	nr_to_scan, gfp_mask, other_free, other_file,
	79	min_adj);
31d59a41 AH	80	rem = global_page_state(NR_ACTIVE_ANON) +
	81	global_page_state(NR_ACTIVE_FILE) +
	82	global_page_state(NR_INACTIVE_ANON) +
	83	global_page_state(NR_INACTIVE_FILE);
f501d001	84	if (nr_to_scan <= 0 \|\| min_adj == OOM_ADJUST_MAX + 1) {
34006e11 DR	85	lowmem_print(5, "lowmem_shrink %d, %x, return %d\n",
34006e11 DR	86	nr_to_scan, gfp_mask, rem);
f501d001 AH	87	return rem;
f501d001 AH	88	}
34006e11	89	selected_oom_adj = min_adj;
f501d001	90
08b88cc7 SM	91	read_lock(&tasklist_lock);
08b88cc7 SM	92	for_each_process(p) {
34006e11 DR	93	int oom_adj;
34006e11 DR	94
5d14a573 DR	95	task_lock(p);
	96	if (!p->mm) {
	97	task_unlock(p);
34006e11	98	continue;
5d14a573	99	}
34006e11	100	oom_adj = p->oomkilladj;
5d14a573 DR	101	if (oom_adj < min_adj) {
5d14a573 DR	102	task_unlock(p);
f501d001	103	continue;
5d14a573	104	}
f501d001	105	tasksize = get_mm_rss(p->mm);
5d14a573	106	task_unlock(p);
f501d001 AH	107	if (tasksize <= 0)
	108	continue;
	109	if (selected) {
34006e11	110	if (oom_adj < selected_oom_adj)
f501d001	111	continue;
34006e11	112	if (oom_adj == selected_oom_adj &&
f501d001 AH	113	tasksize <= selected_tasksize)
f501d001 AH	114	continue;
08b88cc7	115	}
f501d001 AH	116	selected = p;
f501d001 AH	117	selected_tasksize = tasksize;
34006e11	118	selected_oom_adj = oom_adj;
f501d001	119	lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",
34006e11	120	p->pid, p->comm, oom_adj, tasksize);
08b88cc7	121	}
34006e11	122	if (selected) {
08b88cc7 SM	123	lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",
08b88cc7 SM	124	selected->pid, selected->comm,
34006e11	125	selected_oom_adj, selected_tasksize);
08b88cc7 SM	126	force_sig(SIGKILL, selected);
	127	rem -= selected_tasksize;
	128	}
34006e11 DR	129	lowmem_print(4, "lowmem_shrink %d, %x, return %d\n",
34006e11 DR	130	nr_to_scan, gfp_mask, rem);
08b88cc7 SM	131	read_unlock(&tasklist_lock);
	132	return rem;
	133	}
	134
	135	static int __init lowmem_init(void)
	136	{
	137	register_shrinker(&lowmem_shrinker);
	138	return 0;
	139	}
	140
	141	static void __exit lowmem_exit(void)
	142	{
	143	unregister_shrinker(&lowmem_shrinker);
	144	}
	145
	146	module_init(lowmem_init);
	147	module_exit(lowmem_exit);
	148
	149	MODULE_LICENSE("GPL");
	150