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Commit 08b88cc7 authored by San Mehat's avatar San Mehat Committed by Greg Kroah-Hartman
Browse files

Staging: android: add lowmemorykiller driver 



From: San Mehat <san@android.com>
Cc: Brian Swetland <swetland@google.com>
Cc: Robert Love <rlove@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 1fa7026f

drivers/staging/android/Kconfig

+6 −0
Original line number Diff line number Diff line
@@ -77,4 +77,10 @@ config ANDROID_TIMED_GPIO 
	depends on GENERIC_GPIO

	default n



config ANDROID_LOW_MEMORY_KILLER

	bool "Android Low Memory Killer"

	default N

	---help---

	  Register processes to be killed when memory is low



endmenu

drivers/staging/android/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -2,3 +2,4 @@ obj-$(CONFIG_ANDROID_BINDER_IPC) += binder.o 
obj-$(CONFIG_ANDROID_LOGGER)		+= logger.o

obj-$(CONFIG_ANDROID_RAM_CONSOLE)	+= ram_console.o

obj-$(CONFIG_ANDROID_TIMED_GPIO)	+= timed_gpio.o

obj-$(CONFIG_ANDROID_LOW_MEMORY_KILLER)	+= lowmemorykiller.o

drivers/staging/android/lowmemorykiller.c

0 → 100644
+119 −0
Original line number Diff line number Diff line 
/* 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 array_size = ARRAY_SIZE(lowmem_adj);

	int other_free = global_page_state(NR_FREE_PAGES) + 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]) {

			min_adj = lowmem_adj[i];

			break;

		}

	}

	if(nr_to_scan > 0)

		lowmem_print(3, "lowmem_shrink %d, %x, ofree %d, ma %d\n", nr_to_scan, gfp_mask, other_free, min_adj);

	read_lock(&tasklist_lock);

	for_each_process(p) {

		if(p->oomkilladj >= 0 && p->mm) {

			tasksize = get_mm_rss(p->mm);

			if(nr_to_scan > 0 && tasksize > 0 && p->oomkilladj >= min_adj) {

				if(selected == NULL ||

				   p->oomkilladj > selected->oomkilladj ||

				   (p->oomkilladj == selected->oomkilladj &&

				    tasksize > selected_tasksize)) {

					selected = p;

					selected_tasksize = tasksize;

					lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",

					             p->pid, p->comm, p->oomkilladj, tasksize);

				}

			}

			rem += tasksize;

		}

	}

	if(selected != NULL) {

		lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",

		             selected->pid, selected->comm,

		             selected->oomkilladj, 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");