[PATCH v4] oom: add trace points for debugging.
From: KAMEZAWA Hiroyuki
Date: Tue Dec 13 2011 - 04:13:40 EST
Changelog:
- devided into oom tracepoint and task tracepoint.
- task tracepoint traces fork/rename
- oom tracepoint traces modification to oom_score_adj.
dropped acks because of total design changes.
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Subject: [PATCH] tracepoint: add tracepoints for debugging oom_score_adj.
oom_score_adj is used for guarding processes from OOM-Killer. One of problem
is that it's inherited at fork(). When a daemon set oom_score_adj and
make children, it's hard to know where the value is set.
This patch adds some tracepoints useful for debugging. This patch adds
3 trace points.
- creating new task
- renaming a task (exec)
- set oom_score_adj
To debug, users need to enable some trace pointer. Maybe filtering is useful as
# EVENT=/sys/kernel/debug/tracing/events/task/
# echo "oom_score_adj != 0" > $EVENT/task_newtask/filter
# echo "oom_score_adj != 0" > $EVENT/task_rename/filter
# echo 1 > $EVENT/enable
# EVENT=/sys/kernel/debug/tracing/events/oom/
# echo 1 > $EVENT/enable
output will be like this.
# grep oom /sys/kernel/debug/tracing/trace
bash-7699 [007] d..3 5140.744510: oom_score_adj_update: pid=7699 comm=bash oom_score_adj=-1000
bash-7699 [007] ...1 5151.818022: task_newtask: pid=7729 comm=bash clone_flags=1200011 oom_score_adj=-1000
ls-7729 [003] ...2 5151.818504: task_rename: pid=7729 oldcomm=bash newcomm=ls oom_score_adj=-1000
bash-7699 [002] ...1 5175.701468: task_newtask: pid=7730 comm=bash clone_flags=1200011 oom_score_adj=-1000
grep-7730 [007] ...2 5175.701993: task_rename: pid=7730 oldcomm=bash newcomm=grep oom_score_adj=-1000
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
fs/exec.c | 4 +++
fs/proc/base.c | 3 ++
include/trace/events/oom.h | 35 ++++++++++++++++++++++++
include/trace/events/task.h | 63 +++++++++++++++++++++++++++++++++++++++++++
kernel/fork.c | 6 ++++
mm/oom_kill.c | 6 ++++
6 files changed, 117 insertions(+), 0 deletions(-)
create mode 100644 include/trace/events/oom.h
create mode 100644 include/trace/events/task.h
diff --git a/fs/exec.c b/fs/exec.c
index ca141db..fd0bfbd 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -59,6 +59,8 @@
#include <asm/uaccess.h>
#include <asm/mmu_context.h>
#include <asm/tlb.h>
+
+#include <trace/events/task.h>
#include "internal.h"
int core_uses_pid;
@@ -1054,6 +1056,8 @@ void set_task_comm(struct task_struct *tsk, char *buf)
{
task_lock(tsk);
+ trace_task_rename(tsk, buf);
+
/*
* Threads may access current->comm without holding
* the task lock, so write the string carefully.
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 1050b1c..f201e64 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -87,6 +87,7 @@
#ifdef CONFIG_HARDWALL
#include <asm/hardwall.h>
#endif
+#include <trace/events/oom.h>
#include "internal.h"
/* NOTE:
@@ -1166,6 +1167,7 @@ static ssize_t oom_adjust_write(struct file *file, const char __user *buf,
else
task->signal->oom_score_adj = (oom_adjust * OOM_SCORE_ADJ_MAX) /
-OOM_DISABLE;
+ trace_oom_score_adj_update(task);
err_sighand:
unlock_task_sighand(task, &flags);
err_task_lock:
@@ -1253,6 +1255,7 @@ static ssize_t oom_score_adj_write(struct file *file, const char __user *buf,
task->signal->oom_score_adj = oom_score_adj;
if (has_capability_noaudit(current, CAP_SYS_RESOURCE))
task->signal->oom_score_adj_min = oom_score_adj;
+ trace_oom_score_adj_update(task);
/*
* Scale /proc/pid/oom_adj appropriately ensuring that OOM_DISABLE is
* always attainable.
diff --git a/include/trace/events/oom.h b/include/trace/events/oom.h
new file mode 100644
index 0000000..bb75e5c
--- /dev/null
+++ b/include/trace/events/oom.h
@@ -0,0 +1,35 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM oom
+
+#if !defined(_TRACE_OOM_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_OOM_H
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(oom_score_adj_update,
+
+ TP_PROTO(struct task_struct *task),
+
+ TP_ARGS(task),
+
+ TP_STRUCT__entry(
+ __field( pid_t, pid)
+ __array( char, comm, TASK_COMM_LEN )
+ __field( int, oom_score_adj)
+ ),
+
+ TP_fast_assign(
+ __entry->pid = task->pid;
+ memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
+ __entry->oom_score_adj = task->signal->oom_score_adj;
+ ),
+
+ TP_printk("pid=%d comm=%s oom_score_adj=%d",
+ __entry->pid, __entry->comm, __entry->oom_score_adj)
+);
+
+#endif
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
+
+
diff --git a/include/trace/events/task.h b/include/trace/events/task.h
new file mode 100644
index 0000000..2ac7484
--- /dev/null
+++ b/include/trace/events/task.h
@@ -0,0 +1,63 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM task
+
+#if !defined(_TRACE_TASK_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_TASK_H
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(task_newtask,
+
+ TP_PROTO(struct task_struct *task, unsigned long clone_flags),
+
+ TP_ARGS(task, clone_flags),
+
+ TP_STRUCT__entry(
+ __field( pid_t, pid)
+ __array( char, comm, TASK_COMM_LEN)
+ __field( unsigned long, clone_flags)
+ __field( int, oom_score_adj)
+ ),
+
+ TP_fast_assign(
+ __entry->pid = task->pid;
+ memcpy(__entry->comm, task->comm, TASK_COMM_LEN);
+ __entry->clone_flags = clone_flags;
+ __entry->oom_score_adj = task->signal->oom_score_adj;
+ ),
+
+ TP_printk("pid=%d comm=%s clone_flags=%lx oom_score_adj=%d",
+ __entry->pid, __entry->comm,
+ __entry->clone_flags, __entry->oom_score_adj)
+);
+
+TRACE_EVENT(task_rename,
+
+ TP_PROTO(struct task_struct *task, char *comm),
+
+ TP_ARGS(task, comm),
+
+ TP_STRUCT__entry(
+ __field( pid_t, pid)
+ __array( char, oldcomm, TASK_COMM_LEN)
+ __array( char, newcomm, TASK_COMM_LEN)
+ __field( int, oom_score_adj)
+ ),
+
+ TP_fast_assign(
+ __entry->pid = task->pid;
+ memcpy(entry->oldcomm, task->comm, TASK_COMM_LEN);
+ memcpy(entry->newcomm, comm, TASK_COMM_LEN);
+ __entry->oom_score_adj = task->signal->oom_score_adj;
+ ),
+
+ TP_printk("pid=%d oldcomm=%s newcomm=%s oom_score_adj=%d",
+ __entry->pid, __entry->oldcomm,
+ __entry->newcomm, __entry->oom_score_adj)
+);
+
+#endif
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
+
+
diff --git a/kernel/fork.c b/kernel/fork.c
index e20518d..d93ef13 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -77,6 +77,9 @@
#include <trace/events/sched.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/task.h>
+
/*
* Protected counters by write_lock_irq(&tasklist_lock)
*/
@@ -1390,6 +1393,9 @@ static struct task_struct *copy_process(unsigned long clone_flags,
if (clone_flags & CLONE_THREAD)
threadgroup_fork_read_unlock(current);
perf_event_fork(p);
+
+ trace_task_newtask(p, clone_flags);
+
return p;
bad_fork_free_pid:
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index e2e1402..46b6d0a 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -33,6 +33,10 @@
#include <linux/security.h>
#include <linux/ptrace.h>
#include <linux/freezer.h>
+#include <linux/ftrace.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/oom.h>
int sysctl_panic_on_oom;
int sysctl_oom_kill_allocating_task;
@@ -55,6 +59,7 @@ void compare_swap_oom_score_adj(int old_val, int new_val)
spin_lock_irq(&sighand->siglock);
if (current->signal->oom_score_adj == old_val)
current->signal->oom_score_adj = new_val;
+ trace_oom_score_adj_update(current);
spin_unlock_irq(&sighand->siglock);
}
@@ -74,6 +79,7 @@ int test_set_oom_score_adj(int new_val)
spin_lock_irq(&sighand->siglock);
old_val = current->signal->oom_score_adj;
current->signal->oom_score_adj = new_val;
+ trace_oom_score_adj_update(current);
spin_unlock_irq(&sighand->siglock);
return old_val;
--
1.7.4.1
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