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-rw-r--r--mm/oom_kill.c259
1 files changed, 111 insertions, 148 deletions
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 0a4ca8a0234b..d3def05a33d9 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -4,6 +4,8 @@
* Copyright (C) 1998,2000 Rik van Riel
* Thanks go out to Claus Fischer for some serious inspiration and
* for goading me into coding this file...
+ * Copyright (C) 2010 Google, Inc.
+ * Rewritten by David Rientjes
*
* The routines in this file are used to kill a process when
* we're seriously out of memory. This gets called from __alloc_pages()
@@ -34,7 +36,6 @@ int sysctl_panic_on_oom;
int sysctl_oom_kill_allocating_task;
int sysctl_oom_dump_tasks = 1;
static DEFINE_SPINLOCK(zone_scan_lock);
-/* #define DEBUG */
#ifdef CONFIG_NUMA
/**
@@ -140,137 +141,76 @@ static bool oom_unkillable_task(struct task_struct *p, struct mem_cgroup *mem,
}
/**
- * badness - calculate a numeric value for how bad this task has been
+ * oom_badness - heuristic function to determine which candidate task to kill
* @p: task struct of which task we should calculate
- * @uptime: current uptime in seconds
+ * @totalpages: total present RAM allowed for page allocation
*
- * The formula used is relatively simple and documented inline in the
- * function. The main rationale is that we want to select a good task
- * to kill when we run out of memory.
- *
- * Good in this context means that:
- * 1) we lose the minimum amount of work done
- * 2) we recover a large amount of memory
- * 3) we don't kill anything innocent of eating tons of memory
- * 4) we want to kill the minimum amount of processes (one)
- * 5) we try to kill the process the user expects us to kill, this
- * algorithm has been meticulously tuned to meet the principle
- * of least surprise ... (be careful when you change it)
+ * The heuristic for determining which task to kill is made to be as simple and
+ * predictable as possible. The goal is to return the highest value for the
+ * task consuming the most memory to avoid subsequent oom failures.
*/
-unsigned long badness(struct task_struct *p, struct mem_cgroup *mem,
- const nodemask_t *nodemask, unsigned long uptime)
+unsigned int oom_badness(struct task_struct *p, struct mem_cgroup *mem,
+ const nodemask_t *nodemask, unsigned long totalpages)
{
- unsigned long points, cpu_time, run_time;
- struct task_struct *child;
- struct task_struct *c, *t;
- int oom_adj = p->signal->oom_adj;
- struct task_cputime task_time;
- unsigned long utime;
- unsigned long stime;
+ int points;
if (oom_unkillable_task(p, mem, nodemask))
return 0;
- if (oom_adj == OOM_DISABLE)
- return 0;
p = find_lock_task_mm(p);
if (!p)
return 0;
/*
- * The memory size of the process is the basis for the badness.
- */
- points = p->mm->total_vm;
- task_unlock(p);
-
- /*
- * swapoff can easily use up all memory, so kill those first.
- */
- if (p->flags & PF_OOM_ORIGIN)
- return ULONG_MAX;
-
- /*
- * Processes which fork a lot of child processes are likely
- * a good choice. We add half the vmsize of the children if they
- * have an own mm. This prevents forking servers to flood the
- * machine with an endless amount of children. In case a single
- * child is eating the vast majority of memory, adding only half
- * to the parents will make the child our kill candidate of choice.
+ * Shortcut check for OOM_SCORE_ADJ_MIN so the entire heuristic doesn't
+ * need to be executed for something that cannot be killed.
*/
- t = p;
- do {
- list_for_each_entry(c, &t->children, sibling) {
- child = find_lock_task_mm(c);
- if (child) {
- if (child->mm != p->mm)
- points += child->mm->total_vm/2 + 1;
- task_unlock(child);
- }
- }
- } while_each_thread(p, t);
+ if (p->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
+ task_unlock(p);
+ return 0;
+ }
/*
- * CPU time is in tens of seconds and run time is in thousands
- * of seconds. There is no particular reason for this other than
- * that it turned out to work very well in practice.
+ * When the PF_OOM_ORIGIN bit is set, it indicates the task should have
+ * priority for oom killing.
*/
- thread_group_cputime(p, &task_time);
- utime = cputime_to_jiffies(task_time.utime);
- stime = cputime_to_jiffies(task_time.stime);
- cpu_time = (utime + stime) >> (SHIFT_HZ + 3);
-
-
- if (uptime >= p->start_time.tv_sec)
- run_time = (uptime - p->start_time.tv_sec) >> 10;
- else
- run_time = 0;
-
- if (cpu_time)
- points /= int_sqrt(cpu_time);
- if (run_time)
- points /= int_sqrt(int_sqrt(run_time));
+ if (p->flags & PF_OOM_ORIGIN) {
+ task_unlock(p);
+ return 1000;
+ }
/*
- * Niced processes are most likely less important, so double
- * their badness points.
+ * The memory controller may have a limit of 0 bytes, so avoid a divide
+ * by zero, if necessary.
*/
- if (task_nice(p) > 0)
- points *= 2;
+ if (!totalpages)
+ totalpages = 1;
/*
- * Superuser processes are usually more important, so we make it
- * less likely that we kill those.
+ * The baseline for the badness score is the proportion of RAM that each
+ * task's rss and swap space use.
*/
- if (has_capability_noaudit(p, CAP_SYS_ADMIN) ||
- has_capability_noaudit(p, CAP_SYS_RESOURCE))
- points /= 4;
+ points = (get_mm_rss(p->mm) + get_mm_counter(p->mm, MM_SWAPENTS)) * 1000 /
+ totalpages;
+ task_unlock(p);
/*
- * We don't want to kill a process with direct hardware access.
- * Not only could that mess up the hardware, but usually users
- * tend to only have this flag set on applications they think
- * of as important.
+ * Root processes get 3% bonus, just like the __vm_enough_memory()
+ * implementation used by LSMs.
*/
- if (has_capability_noaudit(p, CAP_SYS_RAWIO))
- points /= 4;
+ if (has_capability_noaudit(p, CAP_SYS_ADMIN))
+ points -= 30;
/*
- * Adjust the score by oom_adj.
+ * /proc/pid/oom_score_adj ranges from -1000 to +1000 such that it may
+ * either completely disable oom killing or always prefer a certain
+ * task.
*/
- if (oom_adj) {
- if (oom_adj > 0) {
- if (!points)
- points = 1;
- points <<= oom_adj;
- } else
- points >>= -(oom_adj);
- }
+ points += p->signal->oom_score_adj;
-#ifdef DEBUG
- printk(KERN_DEBUG "OOMkill: task %d (%s) got %lu points\n",
- p->pid, p->comm, points);
-#endif
- return points;
+ if (points < 0)
+ return 0;
+ return (points < 1000) ? points : 1000;
}
/*
@@ -278,12 +218,20 @@ unsigned long badness(struct task_struct *p, struct mem_cgroup *mem,
*/
#ifdef CONFIG_NUMA
static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
- gfp_t gfp_mask, nodemask_t *nodemask)
+ gfp_t gfp_mask, nodemask_t *nodemask,
+ unsigned long *totalpages)
{
struct zone *zone;
struct zoneref *z;
enum zone_type high_zoneidx = gfp_zone(gfp_mask);
+ bool cpuset_limited = false;
+ int nid;
+ /* Default to all available memory */
+ *totalpages = totalram_pages + total_swap_pages;
+
+ if (!zonelist)
+ return CONSTRAINT_NONE;
/*
* Reach here only when __GFP_NOFAIL is used. So, we should avoid
* to kill current.We have to random task kill in this case.
@@ -293,26 +241,37 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
return CONSTRAINT_NONE;
/*
- * The nodemask here is a nodemask passed to alloc_pages(). Now,
- * cpuset doesn't use this nodemask for its hardwall/softwall/hierarchy
- * feature. mempolicy is an only user of nodemask here.
- * check mempolicy's nodemask contains all N_HIGH_MEMORY
+ * This is not a __GFP_THISNODE allocation, so a truncated nodemask in
+ * the page allocator means a mempolicy is in effect. Cpuset policy
+ * is enforced in get_page_from_freelist().
*/
- if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask))
+ if (nodemask && !nodes_subset(node_states[N_HIGH_MEMORY], *nodemask)) {
+ *totalpages = total_swap_pages;
+ for_each_node_mask(nid, *nodemask)
+ *totalpages += node_spanned_pages(nid);
return CONSTRAINT_MEMORY_POLICY;
+ }
/* Check this allocation failure is caused by cpuset's wall function */
for_each_zone_zonelist_nodemask(zone, z, zonelist,
high_zoneidx, nodemask)
if (!cpuset_zone_allowed_softwall(zone, gfp_mask))
- return CONSTRAINT_CPUSET;
+ cpuset_limited = true;
+ if (cpuset_limited) {
+ *totalpages = total_swap_pages;
+ for_each_node_mask(nid, cpuset_current_mems_allowed)
+ *totalpages += node_spanned_pages(nid);
+ return CONSTRAINT_CPUSET;
+ }
return CONSTRAINT_NONE;
}
#else
static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
- gfp_t gfp_mask, nodemask_t *nodemask)
+ gfp_t gfp_mask, nodemask_t *nodemask,
+ unsigned long *totalpages)
{
+ *totalpages = totalram_pages + total_swap_pages;
return CONSTRAINT_NONE;
}
#endif
@@ -323,17 +282,16 @@ static enum oom_constraint constrained_alloc(struct zonelist *zonelist,
*
* (not docbooked, we don't want this one cluttering up the manual)
*/
-static struct task_struct *select_bad_process(unsigned long *ppoints,
- struct mem_cgroup *mem, const nodemask_t *nodemask)
+static struct task_struct *select_bad_process(unsigned int *ppoints,
+ unsigned long totalpages, struct mem_cgroup *mem,
+ const nodemask_t *nodemask)
{
struct task_struct *p;
struct task_struct *chosen = NULL;
- struct timespec uptime;
*ppoints = 0;
- do_posix_clock_monotonic_gettime(&uptime);
for_each_process(p) {
- unsigned long points;
+ unsigned int points;
if (oom_unkillable_task(p, mem, nodemask))
continue;
@@ -365,11 +323,11 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
return ERR_PTR(-1UL);
chosen = p;
- *ppoints = ULONG_MAX;
+ *ppoints = 1000;
}
- points = badness(p, mem, nodemask, uptime.tv_sec);
- if (points > *ppoints || !chosen) {
+ points = oom_badness(p, mem, nodemask, totalpages);
+ if (points > *ppoints) {
chosen = p;
*ppoints = points;
}
@@ -384,7 +342,7 @@ static struct task_struct *select_bad_process(unsigned long *ppoints,
*
* Dumps the current memory state of all system tasks, excluding kernel threads.
* State information includes task's pid, uid, tgid, vm size, rss, cpu, oom_adj
- * score, and name.
+ * value, oom_score_adj value, and name.
*
* If the actual is non-NULL, only tasks that are a member of the mem_cgroup are
* shown.
@@ -396,8 +354,7 @@ static void dump_tasks(const struct mem_cgroup *mem)
struct task_struct *p;
struct task_struct *task;
- printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj "
- "name\n");
+ pr_info("[ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name\n");
for_each_process(p) {
if (p->flags & PF_KTHREAD)
continue;
@@ -414,10 +371,11 @@ static void dump_tasks(const struct mem_cgroup *mem)
continue;
}
- printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3u %3d %s\n",
- task->pid, __task_cred(task)->uid, task->tgid,
- task->mm->total_vm, get_mm_rss(task->mm),
- task_cpu(task), task->signal->oom_adj, task->comm);
+ pr_info("[%5d] %5d %5d %8lu %8lu %3u %3d %5d %s\n",
+ task->pid, __task_cred(task)->uid, task->tgid,
+ task->mm->total_vm, get_mm_rss(task->mm),
+ task_cpu(task), task->signal->oom_adj,
+ task->signal->oom_score_adj, task->comm);
task_unlock(task);
}
}
@@ -427,8 +385,9 @@ static void dump_header(struct task_struct *p, gfp_t gfp_mask, int order,
{
task_lock(current);
pr_warning("%s invoked oom-killer: gfp_mask=0x%x, order=%d, "
- "oom_adj=%d\n",
- current->comm, gfp_mask, order, current->signal->oom_adj);
+ "oom_adj=%d, oom_score_adj=%d\n",
+ current->comm, gfp_mask, order, current->signal->oom_adj,
+ current->signal->oom_score_adj);
cpuset_print_task_mems_allowed(current);
task_unlock(current);
dump_stack();
@@ -468,14 +427,14 @@ static int oom_kill_task(struct task_struct *p, struct mem_cgroup *mem)
#undef K
static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
- unsigned long points, struct mem_cgroup *mem,
- nodemask_t *nodemask, const char *message)
+ unsigned int points, unsigned long totalpages,
+ struct mem_cgroup *mem, nodemask_t *nodemask,
+ const char *message)
{
struct task_struct *victim = p;
struct task_struct *child;
struct task_struct *t = p;
- unsigned long victim_points = 0;
- struct timespec uptime;
+ unsigned int victim_points = 0;
if (printk_ratelimit())
dump_header(p, gfp_mask, order, mem);
@@ -491,7 +450,7 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
}
task_lock(p);
- pr_err("%s: Kill process %d (%s) score %lu or sacrifice child\n",
+ pr_err("%s: Kill process %d (%s) score %d or sacrifice child\n",
message, task_pid_nr(p), p->comm, points);
task_unlock(p);
@@ -501,14 +460,15 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
* parent. This attempts to lose the minimal amount of work done while
* still freeing memory.
*/
- do_posix_clock_monotonic_gettime(&uptime);
do {
list_for_each_entry(child, &t->children, sibling) {
- unsigned long child_points;
+ unsigned int child_points;
- /* badness() returns 0 if the thread is unkillable */
- child_points = badness(child, mem, nodemask,
- uptime.tv_sec);
+ /*
+ * oom_badness() returns 0 if the thread is unkillable
+ */
+ child_points = oom_badness(child, mem, nodemask,
+ totalpages);
if (child_points > victim_points) {
victim = child;
victim_points = child_points;
@@ -546,17 +506,19 @@ static void check_panic_on_oom(enum oom_constraint constraint, gfp_t gfp_mask,
#ifdef CONFIG_CGROUP_MEM_RES_CTLR
void mem_cgroup_out_of_memory(struct mem_cgroup *mem, gfp_t gfp_mask)
{
- unsigned long points = 0;
+ unsigned long limit;
+ unsigned int points = 0;
struct task_struct *p;
check_panic_on_oom(CONSTRAINT_MEMCG, gfp_mask, 0);
+ limit = mem_cgroup_get_limit(mem) >> PAGE_SHIFT;
read_lock(&tasklist_lock);
retry:
- p = select_bad_process(&points, mem, NULL);
+ p = select_bad_process(&points, limit, mem, NULL);
if (!p || PTR_ERR(p) == -1UL)
goto out;
- if (oom_kill_process(p, gfp_mask, 0, points, mem, NULL,
+ if (oom_kill_process(p, gfp_mask, 0, points, limit, mem, NULL,
"Memory cgroup out of memory"))
goto retry;
out:
@@ -681,8 +643,9 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
int order, nodemask_t *nodemask)
{
struct task_struct *p;
+ unsigned long totalpages;
unsigned long freed = 0;
- unsigned long points;
+ unsigned int points;
enum oom_constraint constraint = CONSTRAINT_NONE;
blocking_notifier_call_chain(&oom_notify_list, 0, &freed);
@@ -705,8 +668,8 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
* Check if there were limitations on the allocation (only relevant for
* NUMA) that may require different handling.
*/
- if (zonelist)
- constraint = constrained_alloc(zonelist, gfp_mask, nodemask);
+ constraint = constrained_alloc(zonelist, gfp_mask, nodemask,
+ &totalpages);
check_panic_on_oom(constraint, gfp_mask, order);
read_lock(&tasklist_lock);
@@ -718,14 +681,14 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask,
* non-zero, current could not be killed so we must fallback to
* the tasklist scan.
*/
- if (!oom_kill_process(current, gfp_mask, order, 0, NULL,
- nodemask,
+ if (!oom_kill_process(current, gfp_mask, order, 0, totalpages,
+ NULL, nodemask,
"Out of memory (oom_kill_allocating_task)"))
return;
}
retry:
- p = select_bad_process(&points, NULL,
+ p = select_bad_process(&points, totalpages, NULL,
constraint == CONSTRAINT_MEMORY_POLICY ? nodemask :
NULL);
if (PTR_ERR(p) == -1UL)
@@ -738,8 +701,8 @@ retry:
panic("Out of memory and no killable processes...\n");
}
- if (oom_kill_process(p, gfp_mask, order, points, NULL, nodemask,
- "Out of memory"))
+ if (oom_kill_process(p, gfp_mask, order, points, totalpages, NULL,
+ nodemask, "Out of memory"))
goto retry;
read_unlock(&tasklist_lock);
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-21 16:41:52 +0100