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From: Srivatsa Vaddagiri <vatsa@in.ibm.com>
To: Gautham R Shenoy <ego@in.ibm.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
	Oleg Nesterov <oleg@tv-sign.ru>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Anton Blanchard <anton@samba.org>, Andrew Morton <akpm@osdl.org>,
	Pavel Machek <pavel@ucw.cz>, LKML <linux-kernel@vger.kernel.org>,
	Aneesh Kumar <aneesh.kumar@gmail.com>
Subject: Re: [PATCH] kthread_should_stop_check_freeze (was: Re: [PATCH -mm 3/7] Freezer: Remove PF_NOFREEZE from rcutorture thread)
Date: Tue, 13 Mar 2007 11:12:41 +0530	[thread overview]
Message-ID: <20070313054241.GB19071@in.ibm.com> (raw)
In-Reply-To: <20070313052716.GA11982@in.ibm.com>

On Tue, Mar 13, 2007 at 10:57:16AM +0530, Gautham R Shenoy wrote:
> CPU_DEAD:
> thaw_process(p);
> kthread_stop(p);
> p = NULL;

This neednt guarantee that the thread will see the stop request before
it exits the kthread_should_stop_freeze() function. There will always
be races .. So the only safe way for a thread to know whether it is time
to exit is:

	while (!kthread_should_stop_freeze()) {
		 if (!cpu_online(home_cpu)) 
			goto wait_to_die;

		...

	}

wait_to_die:

	while (!kthread_should_stop()) {
		/* sleep */
	}


-- 
Regards,
vatsa

  reply	other threads:[~2007-03-13  5:35 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-26  7:00 [PATCH -mm 0/6] Freezer changes Rafael J. Wysocki
2007-02-26  7:02 ` [PATCH -mm 1/6] Freezer: Read PF_BORROWED_MM in a nonracy way Rafael J. Wysocki
2007-02-26  7:05 ` [PATCH -mm 2/6] Freezer: Fix memory ordering in refrigerator Rafael J. Wysocki
2007-02-26 11:32   ` Oleg Nesterov
2007-02-26  7:06 ` [PATCH -mm 3/6] Freezer: Close theoretical race between refrigerator and thaw_tasks Rafael J. Wysocki
2007-02-26  7:08 ` [PATCH -mm 4/6] Freezer: Remove PF_NOFREEZE from rcutorture thread Rafael J. Wysocki
2007-02-26  7:11 ` [PATCH -mm 5/6] Freezer: Remove PF_NOFREEZE from bluetooth threads Rafael J. Wysocki
2007-02-26  7:13 ` [PATCH -mm 6/6] Freezer: Add try_to_freeze calls to all kernel threads Rafael J. Wysocki
2007-03-01 15:05 ` [PATCH -mm 0/7] Freezer changes (take 2) Rafael J. Wysocki
2007-03-01 15:06   ` [PATCH -mm 1/7] Freezer: Read PF_BORROWED_MM in a nonracy way Rafael J. Wysocki
2007-03-01 15:08   ` [PATCH -mm 2/7] Freezer: Close theoretical race between refrigerator and thaw_tasks Rafael J. Wysocki
2007-03-01 16:39     ` Pavel Machek
2007-03-01 15:09   ` [PATCH -mm 3/7] Freezer: Remove PF_NOFREEZE from rcutorture thread Rafael J. Wysocki
2007-03-01 19:38     ` Anton Blanchard
2007-03-01 19:54       ` Rafael J. Wysocki
2007-03-02 21:35         ` Paul E. McKenney
2007-03-02 22:16           ` Anton Blanchard
2007-03-02 23:33           ` Oleg Nesterov
2007-03-03  0:58             ` Paul E. McKenney
2007-03-03 17:32               ` Oleg Nesterov
2007-03-04  4:34                 ` Srivatsa Vaddagiri
2007-03-11 17:49                 ` [PATCH] kthread_should_stop_check_freeze (was: Re: [PATCH -mm 3/7] Freezer: Remove PF_NOFREEZE from rcutorture thread) Rafael J. Wysocki
2007-03-12  4:38                   ` Paul E. McKenney
2007-03-12  8:14                     ` Pavel Machek
2007-03-12 11:19                       ` Rafael J. Wysocki
2007-03-12 12:23                         ` Oleg Nesterov
2007-03-12 13:24                           ` [PATCH] kthread_should_stop_check_freeze Cedric Le Goater
2007-03-12 18:25                             ` Rafael J. Wysocki
2007-03-12 22:39                         ` [PATCH] kthread_should_stop_check_freeze (was: Re: [PATCH -mm 3/7] Freezer: Remove PF_NOFREEZE from rcutorture thread) Pavel Machek
2007-03-12 22:45                           ` Anton Blanchard
2007-03-13  3:14                             ` Srivatsa Vaddagiri
2007-03-13  9:16                               ` Christoph Hellwig
2007-03-13  9:58                                 ` Srivatsa Vaddagiri
2007-03-13 10:20                                   ` Christoph Hellwig
2007-03-20 18:08                             ` Pavel Machek
2007-03-13  0:58                           ` Paul E. McKenney
2007-03-20 18:10                             ` Pavel Machek
2007-03-13  5:27                   ` Gautham R Shenoy
2007-03-13  5:42                     ` Srivatsa Vaddagiri [this message]
2007-03-03  1:03             ` [PATCH -mm 3/7] Freezer: Remove PF_NOFREEZE from rcutorture thread Rafael J. Wysocki
2007-03-02  6:57     ` Gautham R Shenoy
2007-03-02 21:46       ` Paul E. McKenney
2007-03-01 15:10   ` [PATCH -mm 4/7] Freezer: Remove PF_NOFREEZE from bluetooth threads Rafael J. Wysocki
2007-03-01 15:12   ` [PATCH -mm 5/7] Freezer: Add try_to_freeze calls to all kernel threads Rafael J. Wysocki
2007-03-01 15:15   ` [PATCH -mm 6/7] Freezer: Fix vfork problem Rafael J. Wysocki
2007-03-01 15:17   ` [PATCH -mm 7/7] Freezer: Take kernel_execve into consideration Rafael J. Wysocki

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