From: Jens Axboe <axboe@suse.de>
To: Brad Chapman <kakadu_croc@yahoo.com>
Cc: "David S. Miller" <davem@redhat.com>, linux-kernel@vger.kernel.org
Subject: Re: brlock_is_locked()?
Date: Fri, 24 Aug 2001 08:49:31 +0200 [thread overview]
Message-ID: <20010824084931.D4064@suse.de> (raw)
In-Reply-To: <20010822.120051.25423285.davem@redhat.com> <20010822190820.57208.qmail@web10904.mail.yahoo.com>
In-Reply-To: <20010822190820.57208.qmail@web10904.mail.yahoo.com>
On Wed, Aug 22 2001, Brad Chapman wrote:
> > (I checked the brlock code and didn't find any schedule()s; there's
> > probably a reason for that).
> >
> > Ummm, this is SMP 101, you can't sleep with a lock held.
> > The global kernel lock is special in this regard, but all
> > other SMP locking primitives may not sleep.
>
> Grrr....I read Rusty's Unreliable Guide to Kernel Locking (twice) and
> still didn't remember that. Guess you have to schedule() yourself.
Errr, like Dave said, _you cannot sleep while holding a lock_. It's not
just that the locking primitives themselves don't sleep, you must not
call schedule() (or any other function that may block/sleep) while
holding a lock. _That's_ SMP 101 :-)
--
Jens Axboe
next prev parent reply other threads:[~2001-08-24 6:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-08-22 13:04 brlock_is_locked()? Brad Chapman
2001-08-22 16:33 ` brlock_is_locked()? Ben LaHaise
2001-08-22 18:00 ` brlock_is_locked()? Brad Chapman
2001-08-22 18:03 ` brlock_is_locked()? David S. Miller
2001-08-22 18:17 ` brlock_is_locked()? Brad Chapman
2001-08-22 18:26 ` brlock_is_locked()? David S. Miller
2001-08-22 18:33 ` brlock_is_locked()? Brad Chapman
2001-08-22 18:47 ` brlock_is_locked()? David S. Miller
2001-08-22 18:53 ` brlock_is_locked()? Brad Chapman
2001-08-22 19:00 ` brlock_is_locked()? David S. Miller
2001-08-22 19:08 ` brlock_is_locked()? Brad Chapman
2001-08-24 6:49 ` Jens Axboe [this message]
2001-08-24 14:11 ` brlock_is_locked()? Brad Chapman
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