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. David -- David Laight: da...@l8s.co.uk