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

/* drivers/misc/lowmemorykiller.c
 *
 * The lowmemorykiller driver lets user-space specify a set of memory thresholds
 * where processes with a range of oom_adj values will get killed. Specify the
 * minimum oom_adj values in /sys/module/lowmemorykiller/parameters/adj and the
 * number of free pages in /sys/module/lowmemorykiller/parameters/minfree. Both
 * files take a comma separated list of numbers in ascending order.
 *
 * For example, write "0,8" to /sys/module/lowmemorykiller/parameters/adj and
 * "1024,4096" to /sys/module/lowmemorykiller/parameters/minfree to kill processes
 * with a oom_adj value of 8 or higher when the free memory drops below 4096 pages
 * and kill processes with a oom_adj value of 0 or higher when the free memory
 * drops below 1024 pages.
 *
 * The driver considers memory used for caches to be free, but if a large
 * percentage of the cached memory is locked this can be very inaccurate
 * and processes may not get killed until the normal oom killer is triggered.
 *
 * 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>
#include <linux/profile.h>
#include <linux/notifier.h>

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;

static struct task_struct *lowmem_deathpending;

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

static int
task_notify_func(struct notifier_block *self, unsigned long val, void *data);

static struct notifier_block task_nb = {
	.notifier_call	= task_notify_func,
};

static int
task_notify_func(struct notifier_block *self, unsigned long val, void *data)
{
	struct task_struct *task = data;
	if (task == lowmem_deathpending) {
		lowmem_deathpending = NULL;
		task_handoff_unregister(&task_nb);
	}
	return NOTIFY_OK;
}

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);

	/*
	 * 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.
	 *
	 * Note: Currently you need CONFIG_PROFILING
	 * for this to work correctly.
	 */
	if (lowmem_deathpending)
		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++) {
		if (other_free < lowmem_minfree[i] &&
		    other_file < lowmem_minfree[i]) {
			min_adj = lowmem_adj[i];
			break;
		}
	}
	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);
		/*
		 * If CONFIG_PROFILING is off, then task_handoff_register()
		 * is a nop. In that case we don't want to stall the killer
		 * by setting lowmem_deathpending.
		 */
#ifdef CONFIG_PROFILING
		lowmem_deathpending = selected;
		task_handoff_register(&task_nb);
#endif
		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;
}

static struct shrinker lowmem_shrinker = {
	.shrink = lowmem_shrink,
	.seeks = DEFAULT_SEEKS * 16
};

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

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

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);

module_init(lowmem_init);
module_exit(lowmem_exit);

MODULE_LICENSE("GPL");
Commit	Line	Data
355b0502 GKH	1	/* drivers/misc/lowmemorykiller.c
	2	*
	3	* The lowmemorykiller driver lets user-space specify a set of memory thresholds
	4	* where processes with a range of oom_adj values will get killed. Specify the
	5	* minimum oom_adj values in /sys/module/lowmemorykiller/parameters/adj and the
	6	* number of free pages in /sys/module/lowmemorykiller/parameters/minfree. Both
	7	* files take a comma separated list of numbers in ascending order.
	8	*
	9	* For example, write "0,8" to /sys/module/lowmemorykiller/parameters/adj and
	10	* "1024,4096" to /sys/module/lowmemorykiller/parameters/minfree to kill processes
	11	* with a oom_adj value of 8 or higher when the free memory drops below 4096 pages
	12	* and kill processes with a oom_adj value of 0 or higher when the free memory
	13	* drops below 1024 pages.
	14	*
	15	* The driver considers memory used for caches to be free, but if a large
	16	* percentage of the cached memory is locked this can be very inaccurate
	17	* and processes may not get killed until the normal oom killer is triggered.
	18	*
	19	* Copyright (C) 2007-2008 Google, Inc.
	20	*
	21	* This software is licensed under the terms of the GNU General Public
	22	* License version 2, as published by the Free Software Foundation, and
	23	* may be copied, distributed, and modified under those terms.
	24	*
	25	* This program is distributed in the hope that it will be useful,
	26	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	27	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	28	* GNU General Public License for more details.
	29	*
	30	*/
	31
	32	#include <linux/module.h>
	33	#include <linux/kernel.h>
	34	#include <linux/mm.h>
	35	#include <linux/oom.h>
	36	#include <linux/sched.h>
4755b72e SM	37	#include <linux/profile.h>
4755b72e SM	38	#include <linux/notifier.h>
355b0502 GKH	39
	40	static uint32_t lowmem_debug_level = 2;
	41	static int lowmem_adj[6] = {
	42	0,
	43	1,
	44	6,
	45	12,
	46	};
	47	static int lowmem_adj_size = 4;
	48	static size_t lowmem_minfree[6] = {
	49	3 * 512, /* 6MB */
	50	2 * 1024, /* 8MB */
	51	4 * 1024, /* 16MB */
	52	16 * 1024, /* 64MB */
	53	};
	54	static int lowmem_minfree_size = 4;
	55
4755b72e SM	56	static struct task_struct *lowmem_deathpending;
4755b72e SM	57
355b0502 GKH	58	#define lowmem_print(level, x...) \
	59	do { \
	60	if (lowmem_debug_level >= (level)) \
	61	printk(x); \
	62	} while (0)
	63
4755b72e SM	64	static int
	65	task_notify_func(struct notifier_block self, unsigned long val, void data);
	66
	67	static struct notifier_block task_nb = {
	68	.notifier_call = task_notify_func,
	69	};
	70
	71	static int
	72	task_notify_func(struct notifier_block self, unsigned long val, void data)
	73	{
	74	struct task_struct *task = data;
	75	if (task == lowmem_deathpending) {
	76	lowmem_deathpending = NULL;
	77	task_handoff_unregister(&task_nb);
	78	}
	79	return NOTIFY_OK;
	80	}
	81
cae9bf11	82	static int lowmem_shrink(struct shrinker s, struct shrink_control sc)
355b0502 GKH	83	{
	84	struct task_struct *p;
	85	struct task_struct *selected = NULL;
	86	int rem = 0;
	87	int tasksize;
	88	int i;
	89	int min_adj = OOM_ADJUST_MAX + 1;
	90	int selected_tasksize = 0;
	91	int selected_oom_adj;
	92	int array_size = ARRAY_SIZE(lowmem_adj);
	93	int other_free = global_page_state(NR_FREE_PAGES);
71b2c82b AH	94	int other_file = global_page_state(NR_FILE_PAGES) -
71b2c82b AH	95	global_page_state(NR_SHMEM);
355b0502	96
4755b72e SM	97	/*
	98	* If we already have a death outstanding, then
	99	* bail out right away; indicating to vmscan
	100	* that we have nothing further to offer on
	101	* this pass.
	102	*
	103	* Note: Currently you need CONFIG_PROFILING
	104	* for this to work correctly.
	105	*/
	106	if (lowmem_deathpending)
	107	return 0;
	108
355b0502 GKH	109	if (lowmem_adj_size < array_size)
	110	array_size = lowmem_adj_size;
	111	if (lowmem_minfree_size < array_size)
	112	array_size = lowmem_minfree_size;
	113	for (i = 0; i < array_size; i++) {
	114	if (other_free < lowmem_minfree[i] &&
	115	other_file < lowmem_minfree[i]) {
	116	min_adj = lowmem_adj[i];
	117	break;
	118	}
	119	}
cae9bf11 CC	120	if (sc->nr_to_scan > 0)
	121	lowmem_print(3, "lowmem_shrink %lu, %x, ofree %d %d, ma %d\n",
	122	sc->nr_to_scan, sc->gfp_mask, other_free, other_file,
355b0502 GKH	123	min_adj);
	124	rem = global_page_state(NR_ACTIVE_ANON) +
	125	global_page_state(NR_ACTIVE_FILE) +
	126	global_page_state(NR_INACTIVE_ANON) +
	127	global_page_state(NR_INACTIVE_FILE);
cae9bf11 CC	128	if (sc->nr_to_scan <= 0 \|\| min_adj == OOM_ADJUST_MAX + 1) {
	129	lowmem_print(5, "lowmem_shrink %lu, %x, return %d\n",
	130	sc->nr_to_scan, sc->gfp_mask, rem);
355b0502 GKH	131	return rem;
	132	}
	133	selected_oom_adj = min_adj;
	134
	135	read_lock(&tasklist_lock);
	136	for_each_process(p) {
	137	struct mm_struct *mm;
23687af9	138	struct signal_struct *sig;
355b0502 GKH	139	int oom_adj;
	140
	141	task_lock(p);
	142	mm = p->mm;
23687af9 CC	143	sig = p->signal;
23687af9 CC	144	if (!mm \|\| !sig) {
355b0502 GKH	145	task_unlock(p);
	146	continue;
	147	}
23687af9	148	oom_adj = sig->oom_adj;
355b0502 GKH	149	if (oom_adj < min_adj) {
	150	task_unlock(p);
	151	continue;
	152	}
	153	tasksize = get_mm_rss(mm);
	154	task_unlock(p);
	155	if (tasksize <= 0)
	156	continue;
	157	if (selected) {
	158	if (oom_adj < selected_oom_adj)
	159	continue;
	160	if (oom_adj == selected_oom_adj &&
	161	tasksize <= selected_tasksize)
	162	continue;
	163	}
	164	selected = p;
	165	selected_tasksize = tasksize;
	166	selected_oom_adj = oom_adj;
	167	lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",
	168	p->pid, p->comm, oom_adj, tasksize);
	169	}
	170	if (selected) {
	171	lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",
	172	selected->pid, selected->comm,
	173	selected_oom_adj, selected_tasksize);
4755b72e SM	174	/*
	175	* If CONFIG_PROFILING is off, then task_handoff_register()
	176	* is a nop. In that case we don't want to stall the killer
	177	* by setting lowmem_deathpending.
	178	*/
	179	#ifdef CONFIG_PROFILING
	180	lowmem_deathpending = selected;
	181	task_handoff_register(&task_nb);
	182	#endif
355b0502 GKH	183	force_sig(SIGKILL, selected);
	184	rem -= selected_tasksize;
	185	}
cae9bf11 CC	186	lowmem_print(4, "lowmem_shrink %lu, %x, return %d\n",
cae9bf11 CC	187	sc->nr_to_scan, sc->gfp_mask, rem);
355b0502 GKH	188	read_unlock(&tasklist_lock);
	189	return rem;
	190	}
	191
	192	static struct shrinker lowmem_shrinker = {
	193	.shrink = lowmem_shrink,
	194	.seeks = DEFAULT_SEEKS * 16
	195	};
	196
	197	static int __init lowmem_init(void)
	198	{
	199	register_shrinker(&lowmem_shrinker);
	200	return 0;
	201	}
	202
	203	static void __exit lowmem_exit(void)
	204	{
	205	unregister_shrinker(&lowmem_shrinker);
	206	}
	207
	208	module_param_named(cost, lowmem_shrinker.seeks, int, S_IRUGO \| S_IWUSR);
	209	module_param_array_named(adj, lowmem_adj, int, &lowmem_adj_size,
	210	S_IRUGO \| S_IWUSR);
	211	module_param_array_named(minfree, lowmem_minfree, uint, &lowmem_minfree_size,
	212	S_IRUGO \| S_IWUSR);
	213	module_param_named(debug_level, lowmem_debug_level, uint, S_IRUGO \| S_IWUSR);
	214
	215	module_init(lowmem_init);
	216	module_exit(lowmem_exit);
	217
	218	MODULE_LICENSE("GPL");
	219