RFC Replace PID implementation with IDR API

This patch series replaces kernel bitmap implementation of PID allocation with IDR API.

The following are the stats for pid and pid_namespace object files before and after the replacement. There is a noteworthy change between the IDR and bitmap implementation.

Before
text data bss dec hex filename
8447 3894 64 12405 3075 kernel/pid.o
After
text data bss dec hex filename
3602 324 8 3934 f5e kernel/pid.o

Before
text data bss dec hex filename
5692 1842 192 7726 1e2e kernel/pid_namespace.o
After
text data bss dec hex filename
2858 216 16 3090 c12 kernel/pid_namespace.o

There wasn't a considerable difference between the time required for allocation of PIDs to the processes. The IDR implementation is a little faster than bitmap implementation.

The next change in the pipeline is replacing pidhash with IDR API implementation.

Gargi Sharma (2):
proc: Return if nothing to unmount
pid: Replace PID bitmap implementation with IDR API

 fs/proc/base.c                |   4 +
 include/linux/pid.h           |   1 +
 include/linux/pid_namespace.h |   5 +-
 init/main.c                   |   4 +-
 kernel/pid.c                  | 204 ++++++++----------------------------------
 kernel/pid_namespace.c        |  39 ++++----
 6 files changed, 63 insertions(+), 194 deletions(-)

2.7.4