From: ebiederm@xmission.com (Eric W. Biederman)
To: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Andrew Morton <akpm@osdl.org>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
"Paul E. McKenney" <paulmck@us.ibm.com>,
David Howells <dhowells@redhat.com>
Subject: Re: [PATCH 2/6] relax sig_needs_tasklist()
Date: Sat, 25 Feb 2006 09:17:22 -0700 [thread overview]
Message-ID: <m1r75r1kh9.fsf@ebiederm.dsl.xmission.com> (raw)
In-Reply-To: <43FCEE08.7923E800@tv-sign.ru> (Oleg Nesterov's message of "Thu, 23 Feb 2006 02:04:40 +0300")
Oleg Nesterov <oleg@tv-sign.ru> writes:
> handle_stop_signal() does not need tasklist_lock for
> SIG_KERNEL_STOP_MASK signals anymore.
Small question.
If I read the code correctly the only thing handle_stop_signal needs
the tasklist_lock for is to protect task->parent, for the
do_notify_parent_cldstop(...) case.
If this is correct. I think I see a path to kill read_lock(&tasklist_lock)
completely.
- Protect task->parent with the rcu_read_lock && task_lock().
- Use the rcu forms of list_add/list_del on the tasklist.
- replace read_lock(&tasklist_lock) with rcu_read_lock().
- Make tasklist_lock a simple spin lock.
Comments?
Eric
next prev parent reply other threads:[~2006-02-25 16:18 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-02-22 23:04 Oleg Nesterov
2006-02-25 16:17 ` Eric W. Biederman [this message]
2006-02-25 20:06 ` Oleg Nesterov
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