From: "Rafael J. Wysocki" <rjw@sisk.pl>
To: Pavel Machek <pavel@ucw.cz>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Oleg Nesterov <oleg@tv-sign.ru>,
Anton Blanchard <anton@samba.org>, Andrew Morton <akpm@osdl.org>,
LKML <linux-kernel@vger.kernel.org>,
Aneesh Kumar <aneesh.kumar@gmail.com>,
Srivatsa Vaddagiri <vatsa@in.ibm.com>,
Gautham R Shenoy <ego@in.ibm.com>
Subject: Re: [PATCH] kthread_should_stop_check_freeze (was: Re: [PATCH -mm 3/7] Freezer: Remove PF_NOFREEZE from rcutorture thread)
Date: Mon, 12 Mar 2007 12:19:11 +0100 [thread overview]
Message-ID: <200703121219.12072.rjw@sisk.pl> (raw)
In-Reply-To: <20070312081459.GI5242@elf.ucw.cz>
Hi,
On Monday, 12 March 2007 09:14, Pavel Machek wrote:
> Hi!
>
> > > > I personally think we should do the opposite, add kthread_should_stop_check_freeze()
> > > > or something. kthread_should_stop() is like signal_pending(), we can use
> > > > it under spin_lock (and it is probably used this way by some out-of-tree
> > > > driver). The new helper is obviously "might_sleep()".
> > >
> > > Something like this, perhaps:
> >
> > Looks good to me! The other kthread_should_stop() calls in
> > rcutorture.c should also become kthread_should_top_check_freeze().
> >
> > Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> >
> > > include/linux/kthread.h | 1 +
> > > kernel/kthread.c | 16 ++++++++++++++++
> > > kernel/rcutorture.c | 5 ++---
> > > 3 files changed, 19 insertions(+), 3 deletions(-)
> > >
> > > Index: linux-2.6.21-rc3-mm2/kernel/kthread.c
> > > ===================================================================
> > > --- linux-2.6.21-rc3-mm2.orig/kernel/kthread.c 2007-03-08 21:58:48.000000000 +0100
> > > +++ linux-2.6.21-rc3-mm2/kernel/kthread.c 2007-03-11 18:32:59.000000000 +0100
> > > @@ -13,6 +13,7 @@
> > > #include <linux/file.h>
> > > #include <linux/module.h>
> > > #include <linux/mutex.h>
> > > +#include <linux/freezer.h>
> > > #include <asm/semaphore.h>
> > >
> > > /*
> > > @@ -60,6 +61,21 @@ int kthread_should_stop(void)
> > > }
> > > EXPORT_SYMBOL(kthread_should_stop);
> > >
> > > +/**
> > > + * kthread_should_stop_check_freeze - check if the thread should return now and
> > > + * if not, check if there is a freezing request pending for it.
> > > + */
> > > +int kthread_should_stop_check_freeze(void)
> > > +{
> > > + might_sleep();
> > > + if (kthread_stop_info.k == current)
> > > + return 1;
> > > +
> > > + try_to_freeze();
> > > + return 0;
> > > +}
>
> Can we get better name for this function?
Well, I took the name from the Oleg's message. Can you please suggest
something?
> Why is it useful?
Because we want to avoid repeating
while (!kthread_should_stop()) {
try_to_freeze();
...
}
in many places?
> Caller can do "try_to_freeze()" as well, no?
Sure, it just eliminates one line of code.
> > > }
> > > rcu_torture_current_version++;
> > > oldbatch = cur_ops->completed();
> > > - try_to_freeze();
> > > - } while (!kthread_should_stop() && !fullstop);
> > > + } while (!kthread_should_stop_check_freeze() && !fullstop);
> > > VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
> > > - while (!kthread_should_stop())
> > > + while (!kthread_should_stop_check_freeze())
> > > schedule_timeout_uninterruptible(1);
> > > return 0;
>
> Aha, I see, here it probably becomes handy.
>
> Actually, no... I do not see it. Why don't you simply move first
> try_to_freeze() to beggining of the loop and do
>
> - while (!kthread_should_stop()) {
> schedule_timeout_uninterruptible(1);
> try_to_freeze()
> }
Yes, but then the second loop will contain one more line of code.
Greetings,
Rafael
next prev parent reply other threads:[~2007-03-12 11:16 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 [this message]
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
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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