This patch series replaces kernel bitmap implementation of PID allocation
with IDR API. These patches are written to simplify the kernel by replacing
custom code with calls to generic code.
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
3397 304 0 3701 e75 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
2854 216 16 3086 c0e kernel/pid_namespace.o
The following are the stats for ps, pstree and calling readdir on /proc
for 10,000 processes.
ps:
With IDR API With bitmap
real 0m1.962s 0m2.319s
user 0m0.052s 0m0.060s
sys 0m0.392s 0m0.516s
pstree:
With IDR API With bitmap
real 0m1.062s 0m1.794s
user 0m0.536s 0m0.612s
sys 0m0.184s 0m0.264s
proc:
With IDR API With bitmap
real 0m0.073s 0m0.074s
user 0m0.004s 0m0.004s
sys 0m0.012s 0m0.016s
---
Changes in v5:
- Add rcu lock while iterating over idr tree.
- Fix checkpatch issues.
Changes in v4:
- Make comments for alloc_pid clearer.
Changes in v3:
- Replace idr_next with idr_get_cursor().
- Correct pid_alloc so that find_pid_ns can't
find not completely allocated pids.
Changes in v2:
- Removed redundant IDR function that was introduced
in the previous patchset.
- Renamed PIDNS_HASH_ADDING
- Used idr_for_each_entry_continue()
- Used idr_find() to lookup pids
Gargi Sharma (2):
pid: Replace pid bitmap implementation with IDR API
pid: Remove pidhash
arch/powerpc/platforms/cell/spufs/sched.c | 2 +-
fs/proc/loadavg.c | 2 +-
include/linux/init_task.h | 1 -
include/linux/pid.h | 2 -
include/linux/pid_namespace.h | 18 +--
init/main.c | 3 +-
kernel/fork.c | 2 +-
kernel/pid.c | 246 ++++++------------------------
kernel/pid_namespace.c | 49 +++---
9 files changed, 71 insertions(+), 254 deletions(-)
--
2.7.4
