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Staging: android: lowmemorykiller.c: fix it for "oom: move oom_adj value from task_st...
[~shefty/rdma-dev.git] / drivers / staging / android / lowmemorykiller.c
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...)                       \
45         do {                                            \
46                 if (lowmem_debug_level >= (level))      \
47                         printk(x);                      \
48         } while (0)
49
50 module_param_named(cost, lowmem_shrinker.seeks, int, S_IRUGO | S_IWUSR);
51 module_param_array_named(adj, lowmem_adj, int, &lowmem_adj_size,
52                          S_IRUGO | S_IWUSR);
53 module_param_array_named(minfree, lowmem_minfree, uint, &lowmem_minfree_size,
54                          S_IRUGO | S_IWUSR);
55 module_param_named(debug_level, lowmem_debug_level, uint, S_IRUGO | S_IWUSR);
56
57 static int lowmem_shrink(int nr_to_scan, gfp_t gfp_mask)
58 {
59         struct task_struct *p;
60         struct task_struct *selected = NULL;
61         int rem = 0;
62         int tasksize;
63         int i;
64         int min_adj = OOM_ADJUST_MAX + 1;
65         int selected_tasksize = 0;
66         int selected_oom_adj;
67         int array_size = ARRAY_SIZE(lowmem_adj);
68         int other_free = global_page_state(NR_FREE_PAGES);
69         int other_file = global_page_state(NR_FILE_PAGES);
70
71         if (lowmem_adj_size < array_size)
72                 array_size = lowmem_adj_size;
73         if (lowmem_minfree_size < array_size)
74                 array_size = lowmem_minfree_size;
75         for (i = 0; i < array_size; i++) {
76                 if (other_free < lowmem_minfree[i] &&
77                     other_file < lowmem_minfree[i]) {
78                         min_adj = lowmem_adj[i];
79                         break;
80                 }
81         }
82         if (nr_to_scan > 0)
83                 lowmem_print(3, "lowmem_shrink %d, %x, ofree %d %d, ma %d\n",
84                              nr_to_scan, gfp_mask, other_free, other_file,
85                              min_adj);
86         rem = global_page_state(NR_ACTIVE_ANON) +
87                 global_page_state(NR_ACTIVE_FILE) +
88                 global_page_state(NR_INACTIVE_ANON) +
89                 global_page_state(NR_INACTIVE_FILE);
90         if (nr_to_scan <= 0 || min_adj == OOM_ADJUST_MAX + 1) {
91                 lowmem_print(5, "lowmem_shrink %d, %x, return %d\n",
92                              nr_to_scan, gfp_mask, rem);
93                 return rem;
94         }
95         selected_oom_adj = min_adj;
96
97         read_lock(&tasklist_lock);
98         for_each_process(p) {
99                 struct mm_struct *mm;
100                 int oom_adj;
101
102                 task_lock(p);
103                 mm = p->mm;
104                 if (!mm) {
105                         task_unlock(p);
106                         continue;
107                 }
108                 oom_adj = mm->oom_adj;
109                 if (oom_adj < min_adj) {
110                         task_unlock(p);
111                         continue;
112                 }
113                 tasksize = get_mm_rss(mm);
114                 task_unlock(p);
115                 if (tasksize <= 0)
116                         continue;
117                 if (selected) {
118                         if (oom_adj < selected_oom_adj)
119                                 continue;
120                         if (oom_adj == selected_oom_adj &&
121                             tasksize <= selected_tasksize)
122                                 continue;
123                 }
124                 selected = p;
125                 selected_tasksize = tasksize;
126                 selected_oom_adj = oom_adj;
127                 lowmem_print(2, "select %d (%s), adj %d, size %d, to kill\n",
128                              p->pid, p->comm, oom_adj, tasksize);
129         }
130         if (selected) {
131                 lowmem_print(1, "send sigkill to %d (%s), adj %d, size %d\n",
132                              selected->pid, selected->comm,
133                              selected_oom_adj, selected_tasksize);
134                 force_sig(SIGKILL, selected);
135                 rem -= selected_tasksize;
136         }
137         lowmem_print(4, "lowmem_shrink %d, %x, return %d\n",
138                      nr_to_scan, gfp_mask, rem);
139         read_unlock(&tasklist_lock);
140         return rem;
141 }
142
143 static int __init lowmem_init(void)
144 {
145         register_shrinker(&lowmem_shrinker);
146         return 0;
147 }
148
149 static void __exit lowmem_exit(void)
150 {
151         unregister_shrinker(&lowmem_shrinker);
152 }
153
154 module_init(lowmem_init);
155 module_exit(lowmem_exit);
156
157 MODULE_LICENSE("GPL");
158