0984e56a65
Move module_params to near the end of the source file so that their references are already known/defined. Fixes build errors: drivers/staging/android/lowmemorykiller.c: In function '__check_cost': drivers/staging/android/lowmemorykiller.c:60: error: 'lowmem_shrinker' undeclared (first use in this function) drivers/staging/android/lowmemorykiller.c: At top level: drivers/staging/android/lowmemorykiller.c:60: error: 'lowmem_shrinker' undeclared here (not in a function) drivers/staging/android/lowmemorykiller.c:60: warning: type defaults to 'int' in declaration of 'type name' Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
174 lines
4.9 KiB
C
174 lines
4.9 KiB
C
/* drivers/misc/lowmemorykiller.c
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*
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* The lowmemorykiller driver lets user-space specify a set of memory thresholds
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* where processes with a range of oom_adj values will get killed. Specify the
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* minimum oom_adj values in /sys/module/lowmemorykiller/parameters/adj and the
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* number of free pages in /sys/module/lowmemorykiller/parameters/minfree. Both
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* files take a comma separated list of numbers in ascending order.
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*
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* For example, write "0,8" to /sys/module/lowmemorykiller/parameters/adj and
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* "1024,4096" to /sys/module/lowmemorykiller/parameters/minfree to kill processes
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* with a oom_adj value of 8 or higher when the free memory drops below 4096 pages
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* and kill processes with a oom_adj value of 0 or higher when the free memory
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* drops below 1024 pages.
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*
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* The driver considers memory used for caches to be free, but if a large
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* percentage of the cached memory is locked this can be very inaccurate
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* and processes may not get killed until the normal oom killer is triggered.
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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 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...) \
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do { \
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if (lowmem_debug_level >= (level)) \
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printk(x); \
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} while (0)
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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 selected_oom_adj;
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int array_size = ARRAY_SIZE(lowmem_adj);
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int other_free = global_page_state(NR_FREE_PAGES);
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int other_file = 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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other_file < 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 %d, ma %d\n",
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nr_to_scan, gfp_mask, other_free, other_file,
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min_adj);
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rem = global_page_state(NR_ACTIVE_ANON) +
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global_page_state(NR_ACTIVE_FILE) +
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global_page_state(NR_INACTIVE_ANON) +
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global_page_state(NR_INACTIVE_FILE);
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if (nr_to_scan <= 0 || min_adj == OOM_ADJUST_MAX + 1) {
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lowmem_print(5, "lowmem_shrink %d, %x, return %d\n",
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nr_to_scan, gfp_mask, rem);
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return rem;
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}
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selected_oom_adj = min_adj;
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read_lock(&tasklist_lock);
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for_each_process(p) {
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struct mm_struct *mm;
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int oom_adj;
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task_lock(p);
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mm = p->mm;
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if (!mm) {
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task_unlock(p);
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continue;
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}
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oom_adj = mm->oom_adj;
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if (oom_adj < min_adj) {
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task_unlock(p);
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continue;
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}
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tasksize = get_mm_rss(mm);
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task_unlock(p);
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if (tasksize <= 0)
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continue;
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if (selected) {
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if (oom_adj < selected_oom_adj)
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continue;
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if (oom_adj == selected_oom_adj &&
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tasksize <= selected_tasksize)
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continue;
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}
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selected = p;
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selected_tasksize = tasksize;
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selected_oom_adj = oom_adj;
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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, oom_adj, tasksize);
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}
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if (selected) {
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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_oom_adj, 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",
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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 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 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_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,
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S_IRUGO | S_IWUSR);
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module_param_array_named(minfree, lowmem_minfree, uint, &lowmem_minfree_size,
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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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module_init(lowmem_init);
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module_exit(lowmem_exit);
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MODULE_LICENSE("GPL");
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