Re: io_request_lock/queue_lock patch

[Jonathan Lahr <lahr@us.ibm.com>]

> > Please elaborate on "no, no, no".   Are you suggesting that no further
> > improvements can be made or should be attempted on the 2.4 i/o subsystem?
> 
> Of course not. The no no no just means that attempting to globally remove the
> io_request_lock at this point is a no-go, so don't even go there. The
> sledgehammer approach will not fly at this point, it's just way too risky.

I agree that reducing locking scope is often problematic.  However,
this patch does not globally remove the io_request_lock.  The purpose
of the patch is to protect request queue integrity with a per queue 
lock instead of the global io_request_lock.  My intent was to leave 
other io_request_lock serialization intact.  Any insight into whether
the patch leaves data unprotected would be appreciated.

Jonathan

-- 
Jonathan Lahr
IBM Linux Technology Center
Beaverton, Oregon
lahr@us.ibm.com
503-578-3385