K 10
svn:author
V 8
melifaro
K 8
svn:date
V 27
2012-04-06T06:53:58.341119Z
K 7
svn:log
V 806
- Improve BPF locking model.

Interface locks and descriptor locks are converted from mutex(9) to rwlock(9).
This greately improves performance: in most common case we need to acquire 1
reader lock instead of 2 mutexes.

- Remove filter(descriptor) (reader) lock in bpf_mtap[2]
This was suggested by glebius@. We protect filter by requesting interface
writer lock on filter change.

- Cover struct bpf_if under BPF_INTERNAL define. This permits including bpf.h
without including rwlock stuff. However, this is is temporary solution,
struct bpf_if should be made opaque for any external caller.

Found by:       Dmitrij Tejblum <tejblum@yandex-team.ru>
Sponsored by:   Yandex LLC

Reviewed by:    glebius (previous version)
Reviewed by:    silence on -net@
Approved by:    (mentor)

MFC after:      3 weeks

END