> > we already have kernel_lock, which is exactly to emulate the existing
> > synchronization semantics.
> > why to bother to waste time to introduce and stabilize
> > another stop-gap hack rather than doing real smp work?
> 
> But kernel_lock gives you _one_ level of mutual exclusion.  Unless I
> misunderstand -- which is entirely possible -- what Jonathan is proposing
> would give multiple levels.

right.  of course, any stop-gap hack have some benefit. :-)

my point is, given its complexity and overhead,
it isn't worth to introduce this hack.

YAMAMOTO Takashi