On Thu, Jun 02, 2011 at 09:21:11PM +0100, David Laight wrote: > On Thu, Jun 02, 2011 at 06:54:44PM +0000, David Laight wrote: > > Module Name: src > > Committed By: dsl > > Date: Thu Jun 2 18:54:44 UTC 2011 > > > > Modified Files: > > src/sys/kern: vfs_syscalls.c > > > > Log Message: > > Fix type in comment > > (before I replace the 'l' with 'curlwp') > > Actually I've thought about this some more. > While, on the face of it, removing the 'struct lwp *' parameter to all system > calls might seem an optimisation, I suspect that, especially on systems where > arguments are passed in registers, it is a pessimisation. > > Passing 'l' is a register rename (or copy) so is almost zero cost. > > Recovering curlwp may involve a function call, and is, at best, a real > memory access of global data (possibly via an asm statement) that will > be slow and multiple accesses might need caching in a local anyway.
Well, an amd64 GENERIC kernel grows by 1.5k, and I've given up trying to get an i386 MONOLITHIC to compile - too much crap in compat. David -- David Laight: da...@l8s.co.uk