+++ /dev/null
-/* drivers/misc/lowmemorykiller.c
- *
- * The lowmemorykiller driver lets user-space specify a set of memory thresholds
- * where processes with a range of oom_score_adj values will get killed. Specify
- * the minimum oom_score_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_score_adj value of 8 or higher when the free memory
- * drops below 4096 pages and kill processes with a oom_score_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.
- *
- */
-
-#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
-
-#include <linux/init.h>
-#include <linux/moduleparam.h>
-#include <linux/kernel.h>
-#include <linux/mm.h>
-#include <linux/oom.h>
-#include <linux/sched/signal.h>
-#include <linux/swap.h>
-#include <linux/rcupdate.h>
-#include <linux/profile.h>
-#include <linux/notifier.h>
-
-static u32 lowmem_debug_level = 1;
-static short lowmem_adj[6] = {
- 0,
- 1,
- 6,
- 12,
-};
-
-static int lowmem_adj_size = 4;
-static int lowmem_minfree[6] = {
- 3 * 512, /* 6MB */
- 2 * 1024, /* 8MB */
- 4 * 1024, /* 16MB */
- 16 * 1024, /* 64MB */
-};
-
-static int lowmem_minfree_size = 4;
-
-static unsigned long lowmem_deathpending_timeout;
-
-#define lowmem_print(level, x...) \
- do { \
- if (lowmem_debug_level >= (level)) \
- pr_info(x); \
- } while (0)
-
-static unsigned long lowmem_count(struct shrinker *s,
- struct shrink_control *sc)
-{
- return global_node_page_state(NR_ACTIVE_ANON) +
- global_node_page_state(NR_ACTIVE_FILE) +
- global_node_page_state(NR_INACTIVE_ANON) +
- global_node_page_state(NR_INACTIVE_FILE);
-}
-
-static unsigned long lowmem_scan(struct shrinker *s, struct shrink_control *sc)
-{
- struct task_struct *tsk;
- struct task_struct *selected = NULL;
- unsigned long rem = 0;
- int tasksize;
- int i;
- short min_score_adj = OOM_SCORE_ADJ_MAX + 1;
- int minfree = 0;
- int selected_tasksize = 0;
- short selected_oom_score_adj;
- int array_size = ARRAY_SIZE(lowmem_adj);
- int other_free = global_page_state(NR_FREE_PAGES) - totalreserve_pages;
- int other_file = global_node_page_state(NR_FILE_PAGES) -
- global_node_page_state(NR_SHMEM) -
- total_swapcache_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++) {
- minfree = lowmem_minfree[i];
- if (other_free < minfree && other_file < minfree) {
- min_score_adj = lowmem_adj[i];
- break;
- }
- }
-
- lowmem_print(3, "lowmem_scan %lu, %x, ofree %d %d, ma %hd\n",
- sc->nr_to_scan, sc->gfp_mask, other_free,
- other_file, min_score_adj);
-
- if (min_score_adj == OOM_SCORE_ADJ_MAX + 1) {
- lowmem_print(5, "lowmem_scan %lu, %x, return 0\n",
- sc->nr_to_scan, sc->gfp_mask);
- return 0;
- }
-
- selected_oom_score_adj = min_score_adj;
-
- rcu_read_lock();
- for_each_process(tsk) {
- struct task_struct *p;
- short oom_score_adj;
-
- if (tsk->flags & PF_KTHREAD)
- continue;
-
- p = find_lock_task_mm(tsk);
- if (!p)
- continue;
-
- if (task_lmk_waiting(p) &&
- time_before_eq(jiffies, lowmem_deathpending_timeout)) {
- task_unlock(p);
- rcu_read_unlock();
- return 0;
- }
- oom_score_adj = p->signal->oom_score_adj;
- if (oom_score_adj < min_score_adj) {
- task_unlock(p);
- continue;
- }
- tasksize = get_mm_rss(p->mm);
- task_unlock(p);
- if (tasksize <= 0)
- continue;
- if (selected) {
- if (oom_score_adj < selected_oom_score_adj)
- continue;
- if (oom_score_adj == selected_oom_score_adj &&
- tasksize <= selected_tasksize)
- continue;
- }
- selected = p;
- selected_tasksize = tasksize;
- selected_oom_score_adj = oom_score_adj;
- lowmem_print(2, "select '%s' (%d), adj %hd, size %d, to kill\n",
- p->comm, p->pid, oom_score_adj, tasksize);
- }
- if (selected) {
- task_lock(selected);
- send_sig(SIGKILL, selected, 0);
- if (selected->mm)
- task_set_lmk_waiting(selected);
- task_unlock(selected);
- lowmem_print(1, "Killing '%s' (%d), adj %hd,\n"
- " to free %ldkB on behalf of '%s' (%d) because\n"
- " cache %ldkB is below limit %ldkB for oom_score_adj %hd\n"
- " Free memory is %ldkB above reserved\n",
- selected->comm, selected->pid,
- selected_oom_score_adj,
- selected_tasksize * (long)(PAGE_SIZE / 1024),
- current->comm, current->pid,
- other_file * (long)(PAGE_SIZE / 1024),
- minfree * (long)(PAGE_SIZE / 1024),
- min_score_adj,
- other_free * (long)(PAGE_SIZE / 1024));
- lowmem_deathpending_timeout = jiffies + HZ;
- rem += selected_tasksize;
- }
-
- lowmem_print(4, "lowmem_scan %lu, %x, return %lu\n",
- sc->nr_to_scan, sc->gfp_mask, rem);
- rcu_read_unlock();
- return rem;
-}
-
-static struct shrinker lowmem_shrinker = {
- .scan_objects = lowmem_scan,
- .count_objects = lowmem_count,
- .seeks = DEFAULT_SEEKS * 16
-};
-
-static int __init lowmem_init(void)
-{
- register_shrinker(&lowmem_shrinker);
- return 0;
-}
-device_initcall(lowmem_init);
-
-/*
- * not really modular, but the easiest way to keep compat with existing
- * bootargs behaviour is to continue using module_param here.
- */
-module_param_named(cost, lowmem_shrinker.seeks, int, 0644);
-module_param_array_named(adj, lowmem_adj, short, &lowmem_adj_size, 0644);
-module_param_array_named(minfree, lowmem_minfree, uint, &lowmem_minfree_size,
- 0644);
-module_param_named(debug_level, lowmem_debug_level, uint, 0644);
-
projects / karo-tx-linux.git / commitdiff