Re: [patch] fix ptrace slowness

From: Ingo Molnar
Date: Mon Mar 23 2009 - 11:22:25 EST



* Miklos Szeredi <miklos@xxxxxxxxxx> 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;
}

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