311 lines
8.7 KiB
C
311 lines
8.7 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_score_adj values will get killed. Specify
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* the minimum oom_score_adj values in
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* /sys/module/lowmemorykiller/parameters/adj and the number of free pages in
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* /sys/module/lowmemorykiller/parameters/minfree. Both files take a comma
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* 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
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* processes with a oom_score_adj value of 8 or higher when the free memory
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* drops below 4096 pages and kill processes with a oom_score_adj value of 0 or
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* higher when the free memory 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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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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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#include <linux/swap.h>
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#include <linux/rcupdate.h>
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#include <linux/notifier.h>
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#define CREATE_TRACE_POINTS
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#include "trace/lowmemorykiller.h"
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static uint32_t lowmem_debug_level = 1;
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static short 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 int 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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static unsigned long lowmem_deathpending_timeout;
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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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pr_info(x); \
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} while (0)
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#if defined(CONFIG_ZSWAP)
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extern u64 zswap_pool_pages;
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extern atomic_t zswap_stored_pages;
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#endif
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static int lowmem_shrink(struct shrinker *s, struct shrink_control *sc)
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{
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struct task_struct *tsk;
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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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short min_score_adj = OOM_SCORE_ADJ_MAX + 1;
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int minfree = 0;
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int selected_tasksize = 0;
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short selected_oom_score_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) - totalreserve_pages;
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int other_file = global_page_state(NR_FILE_PAGES) -
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global_page_state(NR_SHMEM) -
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global_page_state(NR_UNEVICTABLE) -
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total_swapcache_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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minfree = lowmem_minfree[i];
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if (other_free < minfree && other_file < minfree) {
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min_score_adj = lowmem_adj[i];
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break;
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}
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}
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if (sc->nr_to_scan > 0)
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lowmem_print(3, "lowmem_shrink %lu, %x, ofree %d %d, ma %hd\n",
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sc->nr_to_scan, sc->gfp_mask, other_free,
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other_file, min_score_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 (sc->nr_to_scan <= 0 || min_score_adj == OOM_SCORE_ADJ_MAX + 1) {
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lowmem_print(5, "lowmem_shrink %lu, %x, return %d\n",
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sc->nr_to_scan, sc->gfp_mask, rem);
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return rem;
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}
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selected_oom_score_adj = min_score_adj;
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rcu_read_lock();
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for_each_process(tsk) {
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struct task_struct *p;
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short oom_score_adj;
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if (tsk->flags & PF_KTHREAD ||
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tsk->state & TASK_UNINTERRUPTIBLE)
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continue;
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p = find_lock_task_mm(tsk);
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if (!p)
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continue;
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if (test_tsk_thread_flag(p, TIF_MEMDIE) &&
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time_before_eq(jiffies, lowmem_deathpending_timeout)) {
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task_unlock(p);
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rcu_read_unlock();
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return 0;
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}
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oom_score_adj = p->signal->oom_score_adj;
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if (oom_score_adj < min_score_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(p->mm);
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#if defined(CONFIG_ZSWAP)
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if (atomic_read(&zswap_stored_pages)) {
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lowmem_print(3, "shown tasksize : %d\n", tasksize);
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tasksize += (int)zswap_pool_pages * get_mm_counter(p->mm, MM_SWAPENTS)
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/ atomic_read(&zswap_stored_pages);
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lowmem_print(3, "real tasksize : %d\n", tasksize);
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}
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#endif
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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_score_adj < selected_oom_score_adj)
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continue;
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if (oom_score_adj == selected_oom_score_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_score_adj = oom_score_adj;
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lowmem_print(2, "select '%s' (%d), adj %hd, size %d, to kill\n",
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p->comm, p->pid, oom_score_adj, tasksize);
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}
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if (selected) {
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long cache_size = other_file * (long)(PAGE_SIZE / 1024);
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long cache_limit = minfree * (long)(PAGE_SIZE / 1024);
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long free = other_free * (long)(PAGE_SIZE / 1024);
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trace_lowmemory_kill(selected, cache_size, cache_limit, free);
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lowmem_print(1, "Killing '%s' (%d), adj %hd,\n" \
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" to free %ldkB on behalf of '%s' (%d) because\n" \
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" cache %ldkB is below limit %ldkB for oom_score_adj %hd\n" \
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" Free memory is %ldkB above reserved\n",
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selected->comm, selected->pid,
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selected_oom_score_adj,
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selected_tasksize * (long)(PAGE_SIZE / 1024),
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current->comm, current->pid,
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cache_size, cache_limit,
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min_score_adj,
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free);
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lowmem_deathpending_timeout = jiffies + HZ;
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set_tsk_thread_flag(selected, TIF_MEMDIE);
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send_sig(SIGKILL, selected, 0);
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rem -= selected_tasksize;
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}
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lowmem_print(4, "lowmem_shrink %lu, %x, return %d\n",
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sc->nr_to_scan, sc->gfp_mask, rem);
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rcu_read_unlock();
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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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#ifdef CONFIG_ANDROID_LOW_MEMORY_KILLER_AUTODETECT_OOM_ADJ_VALUES
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static short lowmem_oom_adj_to_oom_score_adj(short oom_adj)
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{
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if (oom_adj == OOM_ADJUST_MAX)
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return OOM_SCORE_ADJ_MAX;
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else
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return (oom_adj * OOM_SCORE_ADJ_MAX) / -OOM_DISABLE;
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}
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static void lowmem_autodetect_oom_adj_values(void)
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{
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int i;
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short oom_adj;
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short oom_score_adj;
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int array_size = ARRAY_SIZE(lowmem_adj);
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if (lowmem_adj_size < array_size)
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array_size = lowmem_adj_size;
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if (array_size <= 0)
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return;
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oom_adj = lowmem_adj[array_size - 1];
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if (oom_adj > OOM_ADJUST_MAX)
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return;
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oom_score_adj = lowmem_oom_adj_to_oom_score_adj(oom_adj);
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if (oom_score_adj <= OOM_ADJUST_MAX)
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return;
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lowmem_print(1, "lowmem_shrink: convert oom_adj to oom_score_adj:\n");
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for (i = 0; i < array_size; i++) {
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oom_adj = lowmem_adj[i];
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oom_score_adj = lowmem_oom_adj_to_oom_score_adj(oom_adj);
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lowmem_adj[i] = oom_score_adj;
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lowmem_print(1, "oom_adj %d => oom_score_adj %d\n",
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oom_adj, oom_score_adj);
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}
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}
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static int lowmem_adj_array_set(const char *val, const struct kernel_param *kp)
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{
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int ret;
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ret = param_array_ops.set(val, kp);
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/* HACK: Autodetect oom_adj values in lowmem_adj array */
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lowmem_autodetect_oom_adj_values();
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return ret;
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}
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static int lowmem_adj_array_get(char *buffer, const struct kernel_param *kp)
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{
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return param_array_ops.get(buffer, kp);
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}
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static void lowmem_adj_array_free(void *arg)
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{
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param_array_ops.free(arg);
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}
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static struct kernel_param_ops lowmem_adj_array_ops = {
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.set = lowmem_adj_array_set,
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.get = lowmem_adj_array_get,
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.free = lowmem_adj_array_free,
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};
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static const struct kparam_array __param_arr_adj = {
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.max = ARRAY_SIZE(lowmem_adj),
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.num = &lowmem_adj_size,
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.ops = ¶m_ops_short,
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.elemsize = sizeof(lowmem_adj[0]),
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.elem = lowmem_adj,
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};
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#endif
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module_param_named(cost, lowmem_shrinker.seeks, int, S_IRUGO | S_IWUSR);
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#ifdef CONFIG_ANDROID_LOW_MEMORY_KILLER_AUTODETECT_OOM_ADJ_VALUES
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__module_param_call(MODULE_PARAM_PREFIX, adj,
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&lowmem_adj_array_ops,
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.arr = &__param_arr_adj,
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S_IRUGO | S_IWUSR, -1);
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__MODULE_PARM_TYPE(adj, "array of short");
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#else
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module_param_array_named(adj, lowmem_adj, short, &lowmem_adj_size,
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S_IRUGO | S_IWUSR);
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#endif
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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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