From: Oleg Nesterov <oleg@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Miklos Szeredi <miklos@szeredi.hu>,
linux-kernel@vger.kernel.org, peterz@infradead.org,
roland@redhat.com, efault@gmx.de, rjw@sisk.pl, jdike@addtoit.com,
user-mode-linux-devel@lists.sourceforge.net,
torvalds@linux-foundation.org, akpm@linux-foundation.org,
stable@kernel.org
Subject: Re: [patch] fix ptrace slowness
Date: Mon, 23 Mar 2009 16:53:03 +0100 [thread overview]
Message-ID: <20090323155303.GA5528@redhat.com> (raw)
In-Reply-To: <20090323151954.GC21267@elte.hu>
On 03/23, Ingo Molnar wrote:
>
> 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();
What if the caller is a realtime task? We can spin "forever", no?
Oleg.
next prev parent reply other threads:[~2009-03-23 15:53 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-23 15:07 [patch] fix ptrace slowness Miklos Szeredi
2009-03-23 15:19 ` Ingo Molnar
2009-03-23 15:53 ` Oleg Nesterov [this message]
2009-03-23 16:13 ` Ingo Molnar
2009-03-23 16:17 ` Miklos Szeredi
2009-03-23 16:38 ` Ingo Molnar
2009-03-23 19:08 ` Michael Riepe
2009-03-23 16:39 ` [tip:sched/urgent] sched, ptrace: fix UML and " Miklos Szeredi
2009-03-23 17:14 ` Ingo Molnar
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