[RFC 0/2] Replace PID implementation with IDR API

Gargi Sharma
2017-09-09T15:21:05Z

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(-)

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2.7.4