Re: [PATCH 2/4] Convert epoll to a bitlock

Eric Dumazet
2009-02-03T22:16:32Z

Andrew Morton a écrit :
> On Mon, 2 Feb 2009 11:20:09 -0700
> Jonathan Corbet <corbet@lwn.net> wrote:
>
>> Matt Mackall suggested converting epoll's ep_lock to a bitlock as a way of
>> saving space in struct file. This patch makes that change.
>
> hrm. bit_spin_lock() makes people upset (large penguiny people). iirc
> it doesn't have all the correct/well-understood memory/compiler
> ordering semantics which spinlocks have. And lockdep doesn't know about
> it.
>

In a previous attempt (2005), I suggested using a single global lock.

http://search.luky.org/linux-kernel.2005/msg50862.html

Probably an array of hashed spinlocks would be more than enough.