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From: Peter Zijlstra <peterz@infradead.org>
To: Ingo Molnar <mingo@kernel.org>
Cc: Waiman Long <longman@redhat.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	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>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [RFC PATCH 00/12] locking/lockdep: Add a new class of terminal locks
Date: Sat, 10 Nov 2018 15:10:45 +0100	[thread overview]
Message-ID: <20181110141045.GD3339@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20181109080412.GC86700@gmail.com>

On Fri, Nov 09, 2018 at 09:04:12AM +0100, Ingo Molnar wrote:
> BTW., if you are interested in more radical approaches to optimize 
> lockdep, we could also add a static checker via objtool driven call graph 
> analysis, and mark those locks terminal that we can prove are terminal.
> 
> This would require the unified call graph of the kernel image and of all 
> modules to be examined in a final pass, but that's within the principal 
> scope of objtool. (This 'final pass' could also be done during bootup, at 
> least in initial versions.)

Something like this is needed for objtool LTO support as well. I just
dread the build time 'regressions' this will introduce :/

The final link pass is already by far the most expensive part (as
measured in wall-time) of building a kernel, adding more work there
would really suck :/

  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 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
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 [this message]
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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