Re: [PATCH -tip] remove the BKL: Replace BKL in mount/umount syscallswith a mutex

From: Linus Torvalds
Date: Fri Apr 17 2009 - 14:15:42 EST




On Fri, 17 Apr 2009, Jonathan Corbet wrote:

> On Fri, 17 Apr 2009 10:21:06 -0700 (PDT)
> Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> > And I know we had patches for file locking BKL-removal at some point. What
> > happened to them? Were they just broken, or forgotten, or waiting in Jon's
> > tree, or what?
>
> Not in my tree, I've not seen them. I could maybe take a look at that,
> I've just about recovered from my fasync experience...:)

Hmm. It might also just be my fevered imagination. I'd like to say it was
Matthew Wilcox, but really, my mind is going.

Ahh. Bug google backs me up. As long as I have google, I can keep
Alzheimer's at bay: "Negative scalability by removal of lock_kernel()"
thread on lkml back in October 2000. After we had actually done the BKL
removal.

So we actually did apply it (in 2.4.0-test9, and then reverted it again
(in -test11, I think). Google for "file_lock_sem fs/locks.c" and see some
of the discussion. The end result was to go back to the BKL due to Apache
slowdowns.

But I seem to remember a later patch (in the last year or two) from Willy
too. Google doesn't help me, so that's probably just my fevered mind. But
I'm cc'ing Willy anyway.

Linus
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