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-rw-r--r--Documentation/sysctl/vm.txt22
-rw-r--r--kernel/sysctl.c9
-rw-r--r--mm/oom_kill.c49
3 files changed, 75 insertions, 5 deletions
diff --git a/Documentation/sysctl/vm.txt b/Documentation/sysctl/vm.txt
index 24eac1b..8a4863c 100644
--- a/Documentation/sysctl/vm.txt
+++ b/Documentation/sysctl/vm.txt
@@ -32,6 +32,7 @@ Currently, these files are in /proc/sys/vm:
- min_unmapped_ratio
- min_slab_ratio
- panic_on_oom
+- oom_dump_tasks
- oom_kill_allocating_task
- mmap_min_address
- numa_zonelist_order
@@ -232,6 +233,27 @@ according to your policy of failover.
=============================================================
+oom_dump_tasks
+
+Enables a system-wide task dump (excluding kernel threads) to be
+produced when the kernel performs an OOM-killing and includes such
+information as pid, uid, tgid, vm size, rss, cpu, oom_adj score, and
+name. This is helpful to determine why the OOM killer was invoked
+and to identify the rogue task that caused it.
+
+If this is set to zero, this information is suppressed. On very
+large systems with thousands of tasks it may not be feasible to dump
+the memory state information for each one. Such systems should not
+be forced to incur a performance penalty in OOM conditions when the
+information may not be desired.
+
+If this is set to non-zero, this information is shown whenever the
+OOM killer actually kills a memory-hogging task.
+
+The default value is 0.
+
+=============================================================
+
oom_kill_allocating_task
This enables or disables killing the OOM-triggering task in
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 86daaa2..8c98d81 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -67,6 +67,7 @@ extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
extern int sysctl_panic_on_oom;
extern int sysctl_oom_kill_allocating_task;
+extern int sysctl_oom_dump_tasks;
extern int max_threads;
extern int core_uses_pid;
extern int suid_dumpable;
@@ -871,6 +872,14 @@ static struct ctl_table vm_table[] = {
.proc_handler = &proc_dointvec,
},
{
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "oom_dump_tasks",
+ .data = &sysctl_oom_dump_tasks,
+ .maxlen = sizeof(sysctl_oom_dump_tasks),
+ .mode = 0644,
+ .proc_handler = &proc_dointvec,
+ },
+ {
.ctl_name = VM_OVERCOMMIT_RATIO,
.procname = "overcommit_ratio",
.data = &sysctl_overcommit_ratio,
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index ef5084d..4194b9d 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -29,6 +29,7 @@
int sysctl_panic_on_oom;
int sysctl_oom_kill_allocating_task;
+int sysctl_oom_dump_tasks;
static DEFINE_SPINLOCK(zone_scan_mutex);
/* #define DEBUG */
@@ -263,6 +264,41 @@ 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.
+ *
+ * If the actual is non-NULL, only tasks that are a member of the mem_cgroup are
+ * shown.
+ *
+ * Call with tasklist_lock read-locked.
+ */
+static void dump_tasks(const struct mem_cgroup *mem)
+{
+ struct task_struct *g, *p;
+
+ printk(KERN_INFO "[ pid ] uid tgid total_vm rss cpu oom_adj "
+ "name\n");
+ do_each_thread(g, p) {
+ /*
+ * total_vm and rss sizes do not exist for tasks with a
+ * detached mm so there's no need to report them.
+ */
+ if (!p->mm)
+ continue;
+ if (mem && !task_in_mem_cgroup(p, mem))
+ continue;
+
+ task_lock(p);
+ printk(KERN_INFO "[%5d] %5d %5d %8lu %8lu %3d %3d %s\n",
+ p->pid, p->uid, p->tgid, p->mm->total_vm,
+ get_mm_rss(p->mm), (int)task_cpu(p), p->oomkilladj,
+ p->comm);
+ task_unlock(p);
+ } while_each_thread(g, p);
+}
+
+/**
* Send SIGKILL to the selected process irrespective of CAP_SYS_RAW_IO
* flag though it's unlikely that we select a process with CAP_SYS_RAW_IO
* set.
@@ -339,7 +375,8 @@ static int oom_kill_task(struct task_struct *p)
}
static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
- unsigned long points, const char *message)
+ unsigned long points, struct mem_cgroup *mem,
+ const char *message)
{
struct task_struct *c;
@@ -349,6 +386,8 @@ static int oom_kill_process(struct task_struct *p, gfp_t gfp_mask, int order,
current->comm, gfp_mask, order, current->oomkilladj);
dump_stack();
show_mem();
+ if (sysctl_oom_dump_tasks)
+ dump_tasks(mem);
}
/*
@@ -389,7 +428,7 @@ retry:
if (!p)
p = current;
- if (oom_kill_process(p, gfp_mask, 0, points,
+ if (oom_kill_process(p, gfp_mask, 0, points, mem,
"Memory cgroup out of memory"))
goto retry;
out:
@@ -495,7 +534,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order)
switch (constraint) {
case CONSTRAINT_MEMORY_POLICY:
- oom_kill_process(current, gfp_mask, order, points,
+ oom_kill_process(current, gfp_mask, order, points, NULL,
"No available memory (MPOL_BIND)");
break;
@@ -505,7 +544,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order)
/* Fall-through */
case CONSTRAINT_CPUSET:
if (sysctl_oom_kill_allocating_task) {
- oom_kill_process(current, gfp_mask, order, points,
+ oom_kill_process(current, gfp_mask, order, points, NULL,
"Out of memory (oom_kill_allocating_task)");
break;
}
@@ -525,7 +564,7 @@ retry:
panic("Out of memory and no killable processes...\n");
}
- if (oom_kill_process(p, gfp_mask, order, points,
+ if (oom_kill_process(p, gfp_mask, order, points, NULL,
"Out of memory"))
goto retry;
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