[v5 00/39] faster tree-based sysctl implementation

[Lucian Adrian Grijincu <lucian.grijincu@gmail.com>]

Hi,

This is version 5 of a patch series that introduces a faster/leaner
sysctl internal implementation. Due to high number of patches and low
general interest I'll just point you to the tree/branch:

 git://github.com/luciang/linux-2.6-new-sysctl.git  v5-new-sysctl-alg



Eric: I have a separate set of patches that make changes to the rest
      of the kernel. Those patches only change sysctl registrations:
      they replace complex tree registrations (with explicit sysctl
      directories), with registrations of arrays of sysctl files.

      Those patches DON'T depend on anything from this series.

      Examples:
       http://thread.gmane.org/gmane.linux.kernel/1137032/focus=1137089
       http://thread.gmane.org/gmane.linux.kernel/1137032/focus=1137087

      I'd like an OK-GO from you to start sending the patches for
      review to their respective maintainers. Also please say if you
      want to be CCed in those patches.




Changes since v4:
  http://thread.gmane.org/gmane.linux.network/196495/focus=1144143
- rebased on 3.0-rc1
- added a new patch manually register kernel/usermodehelper which
  was added in 3.0-rc1
- minor changes to the "sysctl: simplify find_in_table" patch


Changes since v3:
  http://thread.gmane.org/gmane.linux.network/196495/
- removed a bad patch that shrinked a counter from int to u8


Changes since v2:
  http://thread.gmane.org/gmane.linux.kernel/1137032/focus=3D194748
- added a compatibility layer to support old registering complex
  sysctl trees. This layer will be deleted once all users of the old
  are changed.
- subdirectories and netns correspondent dirs are now held in rbtrees
- split of from the patches that make changes in the rest of the tree
- rebased on top of 2.6.39


Changes since v1:
  http://thread.gmane.org/gmane.linux.kernel/1133667
- rebased on top of 2.6.39-rc6
- split the patch that adds the new algorithm and data structures.
- fixed a few bugs lingering in the old code
- shrinked a reference counter
- added a new reference counter to maintain ownership information
- added method to register an empty sysctl dir and converted some users
- added checks enforcing the rule that a non-netns specific directory may
  not be registered after a netns specific one has already been registered.
- added cookie support: register a piece of data with the header to be
  used to make simple conversions on the ctl_table. This saves memory where





Part 1: introduce compatibility layer:

  sysctl: introduce temporary sysctl wrappers
  sysctl: register only tables of sysctl files


Part 2: minimal changes to sysctl users:

  sysctl: call sysctl_init before the first sysctl registration
  sysctl: no-child: manually register kernel/random
  sysctl: no-child: manually register kernel/usermodehelper
  sysctl: no-child: manually register kernel/keys
  sysctl: no-child: manually register fs/inotify
  sysctl: no-child: manually register fs/epoll
  sysctl: no-child: manually register root tables


Part 3: cleanups simplifying the new algorithm (created when
        asked to break up the new algorithm patch):

  sysctl: faster reimplementation of sysctl_check_table
  sysctl: remove useless ctl_table->parent field
  sysctl: simplify find_in_table
  sysctl: sysctl_head_grab defaults to root header on NULL
  sysctl: delete useless grab_header function
  sysctl: rename ->used to ->ctl_use_refs
  sysctl: rename sysctl_head_grab/finish to sysctl_use_header/unuse
  sysctl: rename sysctl_head_next to sysctl_use_next_header
  sysctl: split ->count into ctl_procfs_refs and ctl_header_refs
  sysctl: rename sysctl_head_get/put to sysctl_proc_inode_get/put
  sysctl: rename (un)use_table to __sysctl_(un)use_header
  sysctl: simplify ->permissions hook
  sysctl: group root-specific operations
  sysctl: introduce ctl_table_group
  sysctl: move removal from list out of start_unregistering


Part 4: new algorithm/data structures:

  sysctl: faster tree-based sysctl implementation


Part 5: checks/warns requested during review:

  sysctl: add duplicate entry and sanity ctl_table checks
  sysctl: alloc ctl_table_header with kmem_cache
  sysctl: check netns-specific registration order respected
  sysctl: warn if registration/unregistration order is not respected
  RFC: sysctl: always perform sysctl checks


Part 6: Eric requested rbtrees for subdirs. I also used rbtrees for
        netns correspondent dirs. Hope that adding rbtrees after
        using the old list-based implementation is good enough.
        The rbtree code complicates things a bit and would uglify
        the patch adding the new algorithm.

  sysctl: reorder members of ctl_table_header (cleanup)
  sysctl: add ctl_type member
  RFC: sysctl: replace subdirectory list with rbtree
  RFC: sysctl: replace netns corresp list with rbtree
  sysctl: union-ize some ctl_table_header fields


Part 7: Eric requested ability to register an empty dir:

  sysctl: add register_sysctl_dir: register an empty sysctl directory


Part 8: unrequested feature I'd like to piggy back :)

  sysctl: add ctl_cookie and ctl_cookie_handler
  sysctl: add cookie to __register_sysctl_paths
  sysctl: add register_net_sysctl_table_net_cookie



 drivers/char/random.c            |   27 +-
 fs/eventpoll.c                   |   22 +-
 fs/notify/inotify/inotify_user.c |   22 +-
 fs/proc/inode.c                  |    2 +-
 fs/proc/proc_sysctl.c            |  236 +++++---
 include/linux/inotify.h          |    2 -
 include/linux/key.h              |    3 -
 include/linux/kmod.h             |    3 -
 include/linux/poll.h             |    2 -
 include/linux/sysctl.h           |  221 +++++---
 include/net/net_namespace.h      |    4 +-
 init/main.c                      |    1 +
 kernel/Makefile                  |    5 +-
 kernel/kmod.c                    |   14 +-
 kernel/sysctl.c                  | 1165 +++++++++++++++++++++++++++-----------
 kernel/sysctl_check.c            |  316 +++++++----
 lib/Kconfig.debug                |    8 -
 net/sysctl_net.c                 |   86 ++--
 security/keys/key.c              |    7 +
 security/keys/sysctl.c           |   18 +-
 20 files changed, 1492 insertions(+), 672 deletions(-)


-- 
 .
..: Lucian