From: Matthew Wilcox <willy@infradead.org>
To: Theodore Ts'o <tytso@mit.edu>
Cc: Byungchul Park <byungchul.park@lge.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
kernel-team@lge.com, linux-block <linux-block@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>, Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH] locking/lockdep: Add CONFIG_LOCKDEP_AGGRESSIVE
Date: Tue, 12 Dec 2017 07:39:16 -0800 [thread overview]
Message-ID: <20171212153916.GA9570@bombadil.infradead.org> (raw)
In-Reply-To: <20171212130343.6nwxip3i4ua24dwr@thunk.org>
On Tue, Dec 12, 2017 at 08:03:43AM -0500, Theodore Ts'o wrote:
> On Tue, Dec 12, 2017 at 02:20:32PM +0900, Byungchul Park wrote:
> > The *problem* is false positives, since locks and waiters in
> > kernel are not classified properly, at the moment, which is just
> > a fact that is not related to cross-release stuff at all. IOW,
> > that would be useful once all locks and waiters are classified
> > correctly. It might take time but the classifying is a must-do
> > we have to keep doing.
>
> This is the wrong attitude. The reason why LOCKDEP was so powerful
> was because it automatically classified locks, instead of requiring
> developers to document the locking hierarchy. Requiring developers to
> have to document and classified locks --- especially when the d*mned
> mechanisms for doign so are so primitive and not even documented ---
> is a complete non-strarter.
That's not fair. We had to annotate i_mutex nesting, for example, and
several other places. crosslock doesn't change anything in this respect,
it's just that the case that you hit every damn day as a filesystem
developer is something that the normal person almost never does.
> So are you willing to take my patch? Or give me permission to keep in
> the ext4 tree?
He sent a patch earlier ...
next prev parent reply other threads:[~2017-12-12 15:39 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-11 3:50 [PATCH] locking/lockdep: Add CONFIG_LOCKDEP_AGGRESSIVE Theodore Ts'o
2017-12-11 3:57 ` Theodore Ts'o
2017-12-11 21:06 ` Linus Torvalds
2017-12-12 1:56 ` Theodore Ts'o
2017-12-12 5:20 ` Byungchul Park
2017-12-12 13:03 ` Theodore Ts'o
2017-12-12 15:39 ` Matthew Wilcox [this message]
2017-12-13 5:33 ` Byungchul Park
2017-12-12 17:00 ` Linus Torvalds
2017-12-13 5:38 ` Byungchul Park
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