that should be better.
The old code counted references to mbuf clusters by using the offset
of the cluster from the start of memory allocated for mbufs and
clusters as an index into an array of chars, which did the reference
counting. If the external storage was not a cluster then reference
counting had to be done by the code using that external storage.
NetBSD's system of linked lists of mbufs was cosidered, but Alfred
felt it would have locking issues when the kernel was made more
SMP friendly.
The system implimented uses a pool of unions to track external
storage. The union contains an int for counting the references and
a pointer for forming a free list. The reference counts are
incremented and decremented atomically and so should be SMP friendly.
This system can track reference counts for any sort of external
storage.
Access to the reference counting stuff is now through macros defined
in mbuf.h, so it should be easier to make changes to the system in
the future.
The possibility of storing the reference count in one of the
referencing mbufs was considered, but was rejected 'cos it would
often leave extra mbufs allocated. Storing the reference count in
the cluster was also considered, but because the external storage
may not be a cluster this isn't an option.
The size of the pool of reference counters is available in the
stats provided by "netstat -m".
PR: 19866
Submitted by: Bosko Milekic <bmilekic@dsuper.net>
Reviewed by: alfred (glanced at by others on -net)
ether_ifdetach().
The former consolidates the operations of if_attach(), ng_ether_attach(),
and bpfattach(). The latter consolidates the corresponding detach operations.
Reviewed by: julian, freebsd-net
iobase + 8 because the I/O address table for RSA98-III starts with +8.
Now, bus_alloc_resource() is used instead of isa_alloc_resourcev() if
device type is RSA98III.
fields, not lex/yacc grammar so it is not an exact match but should be
close enough for most cases.
Deal with 'port?', 'irq?' style specifications. These are parsed as
seperate values in lex/yacc in config(8) but tripped up this helper tool.
deal with filename arguments. It is amazing how much you forget over time.
Thanks to the people that reminded me this. I knew there was an easy way
that didn't involve messing with $argv, filehandles, etc, but just could
not remember - all of my books are on the opposite side of the planet..
