From: Peter Zijlstra <peterz@infradead.org>
To: Waiman Long <longman@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>, Will Deacon <will.deacon@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
linux-mm@kvack.org, Petr Mladek <pmladek@suse.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Tejun Heo <tj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC PATCH 02/12] locking/lockdep: Add a new terminal lock type
Date: Sat, 10 Nov 2018 15:17:34 +0100 [thread overview]
Message-ID: <20181110141734.GF3339@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <1541709268-3766-3-git-send-email-longman@redhat.com>
On Thu, Nov 08, 2018 at 03:34:18PM -0500, Waiman Long wrote:
> A terminal lock is a lock where further locking or unlocking on another
> lock is not allowed. IOW, no forward dependency is permitted.
>
> With such a restriction in place, we don't really need to do a full
> validation of the lock chain involving a terminal lock. Instead,
> we just check if there is any further locking or unlocking on another
> lock when a terminal lock is being held.
> @@ -263,6 +270,7 @@ struct held_lock {
> unsigned int hardirqs_off:1;
> unsigned int references:12; /* 32 bits */
> unsigned int pin_count;
> + unsigned int flags;
> };
I'm thinking we can easily steal some bits off of the pin_count field if
we have to.
next prev parent reply other threads:[~2018-11-10 22:43 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-08 20:34 [RFC PATCH 00/12] locking/lockdep: Add a new class of terminal locks Waiman Long
2018-11-08 20:34 ` [RFC PATCH 01/12] locking/lockdep: Rework lockdep_set_novalidate_class() Waiman Long
2018-11-10 14:14 ` Peter Zijlstra
2018-11-11 0:26 ` Waiman Long
2018-11-11 1:28 ` Peter Zijlstra
2018-11-08 20:34 ` [RFC PATCH 02/12] locking/lockdep: Add a new terminal lock type Waiman Long
2018-11-10 14:17 ` Peter Zijlstra [this message]
2018-11-11 0:28 ` Waiman Long
2018-11-08 20:34 ` [RFC PATCH 03/12] locking/lockdep: Add DEFINE_TERMINAL_SPINLOCK() and related macros Waiman Long
2018-11-08 20:34 ` [RFC PATCH 04/12] printk: Make logbuf_lock a terminal lock Waiman Long
2018-11-08 20:34 ` [RFC PATCH 05/12] debugobjects: Mark pool_lock as " Waiman Long
2018-11-08 20:34 ` [RFC PATCH 06/12] debugobjects: Move printk out of db lock critical sections Waiman Long
2018-11-08 20:34 ` [RFC PATCH 07/12] locking/lockdep: Add support for nested terminal locks Waiman Long
2018-11-10 14:20 ` Peter Zijlstra
2018-11-11 0:30 ` Waiman Long
2018-11-11 1:30 ` Peter Zijlstra
2018-11-08 20:34 ` [RFC PATCH 08/12] debugobjects: Make object hash locks " Waiman Long
2018-11-08 20:34 ` [RFC PATCH 09/12] lib/stackdepot: Make depot_lock a terminal spinlock Waiman Long
2018-11-08 20:34 ` [RFC PATCH 10/12] locking/rwsem: Mark rwsem.wait_lock as a terminal lock Waiman Long
2018-11-08 20:34 ` [RFC PATCH 11/12] cgroup: Mark the rstat percpu lock as terminal Waiman Long
2018-11-08 20:34 ` [RFC PATCH 12/12] mm/kasan: Make quarantine_lock a terminal lock Waiman Long
2018-11-09 8:04 ` [RFC PATCH 00/12] locking/lockdep: Add a new class of terminal locks Ingo Molnar
2018-11-09 15:48 ` Waiman Long
2018-11-12 5:15 ` Ingo Molnar
2018-11-10 14:10 ` Peter Zijlstra
2018-11-10 23:35 ` Waiman Long
2018-11-12 5:10 ` Ingo Molnar
2018-11-12 5:53 ` Josh Poimboeuf
2018-11-12 6:30 ` Ingo Molnar
2018-11-12 22:22 ` Josh Poimboeuf
2018-11-12 22:56 ` Waiman Long
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