Re: uvm_object::vmobjlock

[Antti Kantee <pooka%cs.hut.fi@localhost>]

On Thu Jan 28 2010 at 21:55:53 +0000, Mindaugas Rasiukevicius wrote:
> Hello,
> 
> Unless anyone objects, I would like to change struct uvm_object::vmobjlock to
> be dynamically allocated with mutex_obj_alloc().  It allows us to:  1) share
> the lock among objects by holding a reference  2) avoid false-sharing on 
> locks.
> Note that struct vnode::v_interlock becomes a pointer, which means a chunk of
> mechanical changes.

1) can you give an example of where this is useful?  (i'm not saying it
   isn't, i just don't like thinking ;)
2) really?  looks like for example for vnodes the next 64 bytes starting
   from the interlock (on i386) require taking the interlock anyway.