Re: [patch] fix ptrace slowness

[Ingo Molnar <mingo@elte.hu>]

* Miklos Szeredi <miklos@szeredi.hu> wrote:

> This one incorporates comments from Oleg and Ingo.  Please apply 
> to 2.6.29 and 2.6.2[78]-stable trees.

The fix first needs to go upstream. There's an alternative patch 
below. Would you mind to give it a test? Chances are that it will 
make UML even faster than your fix.

	Ingo

diff --git a/kernel/sched.c b/kernel/sched.c
index 3e827b8..2d60f23 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2119,7 +2119,8 @@ unsigned long wait_task_inactive(struct task_struct *p, long match_state)
 		 * yield - it could be a while.
 		 */
 		if (unlikely(on_rq)) {
-			schedule_timeout_uninterruptible(1);
+			cpu_relax();
+			cond_resched();
 			continue;
 		}