lglock: introduce special lglock and brlock spin locks

lglock: introduce special lglock and brlock spin locks

This patch introduces "local-global" locks (lglocks). These can be used to:

- Provide fast exclusive access to per-CPU data, with exclusive access to
  another CPU's data allowed but possibly subject to contention, and to provide
  very slow exclusive access to all per-CPU data.
- Or to provide very fast and scalable read serialisation, and to provide
  very slow exclusive serialisation of data (not necessarily per-CPU data).

Brlocks are also implemented as a short-hand notation for the latter use
case.

Thanks to Paul for local/global naming convention.

Cc: [email protected]
Cc: Al Viro <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Signed-off-by: Nick Piggin <[email protected]>
Signed-off-by: Al Viro <[email protected]>

0 files changed, 0 insertions, 0 deletions