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![Ingo Molnar](/assets/img/avatar_default.png)
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which will have to be picked up from other headers and a couple of .c files. Create a trivial placeholder <linux/sched/signal.h> file that just maps to <linux/sched.h> to make this patch obviously correct and bisectable. Include the new header in the files that are going to need it. Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
212 lines
6.2 KiB
C
212 lines
6.2 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/init.h>
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#include <linux/moduleparam.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/signal.h>
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#include <linux/swap.h>
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#include <linux/rcupdate.h>
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#include <linux/profile.h>
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#include <linux/notifier.h>
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static u32 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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static unsigned long lowmem_count(struct shrinker *s,
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struct shrink_control *sc)
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{
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return global_node_page_state(NR_ACTIVE_ANON) +
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global_node_page_state(NR_ACTIVE_FILE) +
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global_node_page_state(NR_INACTIVE_ANON) +
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global_node_page_state(NR_INACTIVE_FILE);
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}
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static unsigned long lowmem_scan(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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unsigned long 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_node_page_state(NR_FILE_PAGES) -
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global_node_page_state(NR_SHMEM) -
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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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lowmem_print(3, "lowmem_scan %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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if (min_score_adj == OOM_SCORE_ADJ_MAX + 1) {
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lowmem_print(5, "lowmem_scan %lu, %x, return 0\n",
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sc->nr_to_scan, sc->gfp_mask);
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return 0;
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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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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 (task_lmk_waiting(p) &&
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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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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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task_lock(selected);
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send_sig(SIGKILL, selected, 0);
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if (selected->mm)
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task_set_lmk_waiting(selected);
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task_unlock(selected);
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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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other_file * (long)(PAGE_SIZE / 1024),
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minfree * (long)(PAGE_SIZE / 1024),
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min_score_adj,
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other_free * (long)(PAGE_SIZE / 1024));
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lowmem_deathpending_timeout = jiffies + HZ;
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rem += selected_tasksize;
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}
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lowmem_print(4, "lowmem_scan %lu, %x, return %lu\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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.scan_objects = lowmem_scan,
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.count_objects = lowmem_count,
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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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device_initcall(lowmem_init);
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/*
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* not really modular, but the easiest way to keep compat with existing
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* bootargs behaviour is to continue using module_param here.
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*/
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module_param_named(cost, lowmem_shrinker.seeks, int, 0644);
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module_param_array_named(adj, lowmem_adj, short, &lowmem_adj_size, 0644);
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module_param_array_named(minfree, lowmem_minfree, uint, &lowmem_minfree_size,
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0644);
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module_param_named(debug_level, lowmem_debug_level, uint, 0644);
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