[PATCH v2] sched: print fields name when do sched_show_task

From: Libing Zhou
Date: Thu Aug 13 2020 - 23:03:20 EST


Current sysrq(t) output task fields name are not aligned with
actual task fields value, e.g.:

kernel: sysrq: Show State
kernel: task PC stack pid father
kernel: systemd S12456 1 0 0x00000000
kernel: Call Trace:
kernel: ? __schedule+0x240/0x740

To make it more readable, print fields name together with task fields
value in same line, remove separate fields name print, new format looks
like:

kernel: sysrq: Show State
kernel: task:systemd state:S stack:12920 pid: 1 ppid: 0 flags:0x00000000
kernel: Call Trace:
kernel: __schedule+0x282/0x620

Signed-off-by: Libing Zhou <libing.zhou@xxxxxxxxxxxxxxx>
---
v2:
Quote the new format as well in the changelog per Ingo suggested.

kernel/sched/core.c | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e15543cb8481..0ad554cb0bbb 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6069,10 +6069,10 @@ void sched_show_task(struct task_struct *p)
if (!try_get_task_stack(p))
return;

- printk(KERN_INFO "%-15.15s %c", p->comm, task_state_to_char(p));
+ pr_info("task:%-15.15s state:%c", p->comm, task_state_to_char(p));

if (p->state == TASK_RUNNING)
- printk(KERN_CONT " running task ");
+ pr_cont(" running task ");
#ifdef CONFIG_DEBUG_STACK_USAGE
free = stack_not_used(p);
#endif
@@ -6081,8 +6081,8 @@ void sched_show_task(struct task_struct *p)
if (pid_alive(p))
ppid = task_pid_nr(rcu_dereference(p->real_parent));
rcu_read_unlock();
- printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
- task_pid_nr(p), ppid,
+ pr_cont(" stack:%5lu pid:%5d ppid:%6d flags:0x%08lx\n",
+ free, task_pid_nr(p), ppid,
(unsigned long)task_thread_info(p)->flags);

print_worker_info(KERN_INFO, p);
@@ -6117,13 +6117,6 @@ void show_state_filter(unsigned long state_filter)
{
struct task_struct *g, *p;

-#if BITS_PER_LONG == 32
- printk(KERN_INFO
- " task PC stack pid father\n");
-#else
- printk(KERN_INFO
- " task PC stack pid father\n");
-#endif
rcu_read_lock();
for_each_process_thread(g, p) {
/*
--
2.22.0