sched/debug: Don't dump sched debug info in SysRq-W

commit fb90a6e9 upstream.

sysrq_sched_debug_show() can dump a lot of information.  Don't print out
all that if we're just trying to get a list of blocked tasks (SysRq-W).
The information is still accessible with SysRq-T.
Signed-off-by: Rabin Vincent <rabinv@axis.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1459777322-30902-1-git-send-email-rabin.vincent@axis.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Nikolay Borisov <n.borisov.lkml@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Willy Tarreau <w@1wt.eu>

kernel/sched/core.c

@@ -4745,7 +4745,8 @@ void show_state_filter(unsigned long state_filter)
 	touch_all_softlockup_watchdogs();
 
 #ifdef CONFIG_SCHED_DEBUG
-	sysrq_sched_debug_show();
+	if (!state_filter)
+		sysrq_sched_debug_show();
 #endif
 	rcu_read_unlock();
 	/*