![San Mehat](/assets/img/avatar_default.png)
From: San Mehat <san@android.com> Cc: Brian Swetland <swetland@google.com> Cc: Robert Love <rlove@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
120 lines
3.4 KiB
C
120 lines
3.4 KiB
C
/* drivers/misc/lowmemorykiller.c
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*
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* Copyright (C) 2007-2008 Google, Inc.
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/oom.h>
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#include <linux/sched.h>
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static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask);
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static struct shrinker lowmem_shrinker = {
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.shrink = lowmem_shrink,
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.seeks = DEFAULT_SEEKS * 16
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};
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static uint32_t lowmem_debug_level = 2;
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static int lowmem_adj[6] = {
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0,
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1,
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6,
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12,
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};
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static int lowmem_adj_size = 4;
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static size_t lowmem_minfree[6] = {
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3*512, // 6MB
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2*1024, // 8MB
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4*1024, // 16MB
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16*1024, // 64MB
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};
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static int lowmem_minfree_size = 4;
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#define lowmem_print(level, x...) do { if(lowmem_debug_level >= (level)) printk(x); } while(0)
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module_param_named(cost, lowmem_shrinker.seeks, int, S_IRUGO | S_IWUSR);
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module_param_array_named(adj, lowmem_adj, int, &lowmem_adj_size, S_IRUGO | S_IWUSR);
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module_param_array_named(minfree, lowmem_minfree, uint, &lowmem_minfree_size, S_IRUGO | S_IWUSR);
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module_param_named(debug_level, lowmem_debug_level, uint, S_IRUGO | S_IWUSR);
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static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask)
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{
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struct task_struct *p;
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struct task_struct *selected = NULL;
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int rem = 0;
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int tasksize;
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int i;
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int min_adj = OOM_ADJUST_MAX + 1;
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int selected_tasksize = 0;
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int array_size = ARRAY_SIZE(lowmem_adj);
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int other_free = global_page_state(NR_FREE_PAGES) + global_page_state(NR_FILE_PAGES);
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if(lowmem_adj_size < array_size)
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array_size = lowmem_adj_size;
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if(lowmem_minfree_size < array_size)
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array_size = lowmem_minfree_size;
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for(i = 0; i < array_size; i++) {
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if(other_free < lowmem_minfree[i]) {
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min_adj = lowmem_adj[i];
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break;
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}
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}
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if(nr_to_scan > 0)
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lowmem_print(3, "lowmem_shrink %d, %x, ofree %d, ma %d\n", nr_to_scan, gfp_mask, other_free, min_adj);
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read_lock(&tasklist_lock);
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for_each_process(p) {
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if(p->oomkilladj >= 0 && p->mm) {
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tasksize = get_mm_rss(p->mm);
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if(nr_to_scan > 0 && tasksize > 0 && p->oomkilladj >= min_adj) {
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if(selected == NULL ||
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p->oomkilladj > selected->oomkilladj ||
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(p->oomkilladj == selected->oomkilladj &&
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tasksize > selected_tasksize)) {
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selected = p;
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selected_tasksize = tasksize;
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lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",
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p->pid, p->comm, p->oomkilladj, tasksize);
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}
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}
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rem += tasksize;
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}
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}
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if(selected != NULL) {
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lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",
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selected->pid, selected->comm,
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selected->oomkilladj, selected_tasksize);
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force_sig(SIGKILL, selected);
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rem -= selected_tasksize;
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}
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lowmem_print(4, "lowmem_shrink %d, %x, return %d\n", nr_to_scan, gfp_mask, rem);
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read_unlock(&tasklist_lock);
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return rem;
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}
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static int __init lowmem_init(void)
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{
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register_shrinker(&lowmem_shrinker);
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return 0;
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}
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static void __exit lowmem_exit(void)
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{
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unregister_shrinker(&lowmem_shrinker);
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}
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module_init(lowmem_init);
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module_exit(lowmem_exit);
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MODULE_LICENSE("GPL");
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