Increase NFS_MAXRAHEAD to 32. With 32k read or write requests, that
amounts to 1 Mbyte of read-ahead, enough to cover about 10 ms latency
at gigabit Ethernet speeds. Increase the table of nfsiod kthreads
(NFS_MAXASYNCDAEMON) from 20 to 128, to match the raised value of
NFS_MAXRAHEAD. (Making the limit dynamic requires replacing the
compile-time array with a dynamic structure.)
Add a comment explaining that each read-ahead requires an I/O thread.
Wrap both parameters with an #ifdef <parameter>/#endif, to allow
hand-tuned values or (later) a kernel config-file option override.
the tag before forwarding the packet, make sure the packet+tag is at least
68 bytes long.
This is necessary because our parent will only pad to 64 bytes (ETHER_MIN_LEN)
and some switches will not pad by themselves after deleting a tag.
* don't let cac_ccb_alloc() sleep since it regularly runs in an
interrupt context
* return EAGAIN instead EBUSY (or -1), which is what the upper ld
layer expects to get on transient resource shortages.
* ignore error from cac_ccb_start(), since a `fifo full' condition is
handled internally in the lower layer, i.e. the transaction started
from ldstart() has been queued at the lower layer and must be taken
off ld's disk queue.
Gone are the old kern_sysctl(), cpu_sysctl(), hw_sysctl(),
vfs_sysctl(), etc, routines, along with sysctl_int() et al. Now all
nodes are registered with the tree, and nodes can be added (or
removed) easily, and I/O to and from the tree is handled generically.
Since the nodes are registered with the tree, the mapping from name to
number (and back again) can now be discovered, instead of having to be
hard coded. Adding new nodes to the tree is likewise much simpler --
the new infrastructure handles almost all the work for simple types,
and just about anything else can be done with a small helper function.
All existing nodes are where they were before (numerically speaking),
so all existing consumers of sysctl information should notice no
difference.
PS - I'm sorry, but there's a distinct lack of documentation at the
moment. I'm working on sysctl(3/8/9) right now, and I promise to
watch out for buses.
