[PATCH] SysRq-X: show blocked tasks

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

Useful for debugging IO stalls.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index c64f5bcff947..05810c8d20bc 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -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 */
 };