[sleepy.penguin] [PATCH 0/6] epoll wrapper cleanups

[Eric Wong <normalperson@yhbt.net>]

I've decided to provide lower-level access to epoll users without the
extra overhead of automatic GC marking and Epoll#set management.

The normal Epoll class is now implemented in Ruby, while the low-level
Epoll::IO class is a lightweight C wrapper.  This should make code
easier to maintain, and folks that really want good concurrency can
use Epoll::IO directly (without the GC-safety normal Epoll provides).

I'm also deprecating the Epoll#set and Epoll#delete APIs, since
they're expensive to maintain.  They will be removed in
sleepy_penguin 4.0 (probably 12 months or so).

I've also made Epoll thread-safe for Rubinius, as Rubinius C extensions
do not (or will not) hold any global lock, so the @marks array must be
protected.  Epoll::IO does not need additional locking to be
thread-safe, it uses thread-local storage and the kernel eventpoll
struct is already protected by its internal locking.

Most of these changes have been my experiences in using epoll in recent
years (mostly outside of Ruby) and also close inspection (and some
hacking :) of the epoll implementation in Linux.

I'll document these patches more, later, and push.

 ext/sleepy_penguin/epoll.c       | 633 ++++++---------------------------------
 ext/sleepy_penguin/epoll_green.h |   8 +-
 ext/sleepy_penguin/inotify.c     |  11 +-
 lib/sleepy_penguin.rb            |   1 +
 lib/sleepy_penguin/epoll.rb      | 266 ++++++++++++++++
 test/test_epoll.rb               |  31 +-
 test/test_epoll_io.rb            |  24 ++
 test/test_epoll_optimizations.rb |   2 +-
 8 files changed, 418 insertions(+), 558 deletions(-)