Commit e59e2ae2 authored by Ingo Molnar's avatar Ingo Molnar Committed by Linus Torvalds

[PATCH] SysRq-X: show blocked tasks

Add SysRq-X support: show blocked (TASK_UNINTERRUPTIBLE) tasks only.

Useful for debugging IO stalls.
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 875d95ec
......@@ -182,6 +182,18 @@ static struct sysrq_key_op sysrq_showstate_op = {
.enable_mask = SYSRQ_ENABLE_DUMP,
};
static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty)
{
show_state_filter(TASK_UNINTERRUPTIBLE);
}
static struct sysrq_key_op sysrq_showstate_blocked_op = {
.handler = sysrq_handle_showstate_blocked,
.help_msg = "showBlockedTasks",
.action_msg = "Show Blocked State",
.enable_mask = SYSRQ_ENABLE_DUMP,
};
static void sysrq_handle_showmem(int key, struct tty_struct *tty)
{
show_mem();
......@@ -304,7 +316,7 @@ static struct sysrq_key_op *sysrq_key_table[36] = {
/* May be assigned at init time by SMP VOYAGER */
NULL, /* v */
NULL, /* w */
NULL, /* x */
&sysrq_showstate_blocked_op, /* x */
NULL, /* y */
NULL /* z */
};
......
......@@ -194,7 +194,16 @@ extern void init_idle(struct task_struct *idle, int cpu);
extern cpumask_t nohz_cpu_mask;
extern void show_state(void);
/*
* Only dump TASK_* tasks. (-1 for all tasks)
*/
extern void show_state_filter(unsigned long state_filter);
static inline void show_state(void)
{
show_state_filter(-1);
}
extern void show_regs(struct pt_regs *);
/*
......
......@@ -4804,7 +4804,7 @@ static void show_task(struct task_struct *p)
show_stack(p, NULL);
}
void show_state(void)
void show_state_filter(unsigned long state_filter)
{
struct task_struct *g, *p;
......@@ -4824,11 +4824,16 @@ void show_state(void)
* console might take alot of time:
*/
touch_nmi_watchdog();
show_task(p);
if (p->state & state_filter)
show_task(p);
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
debug_show_all_locks();
/*
* Only show locks if all tasks are dumped:
*/
if (state_filter == -1)
debug_show_all_locks();
}
/**
......
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