linux-kernel - [PATCH v2 0/2] Replace PID bitmap allocation with IDR API

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Date:   Wed, 27 Sep 2017 01:06:01 -0400
From:   Gargi Sharma <gs051095@...il.com>
To:     linux-kernel@...r.kernel.org
Cc:     riel@...riel.com, julia.lawall@...6.fr, akpm@...ux-foundation.org,
        mingo@...nel.org, pasha.tatashin@...cle.com, ktkhai@...tuozzo.com,
        oleg@...hat.com, Gargi Sharma <gs051095@...il.com>
Subject: [PATCH v2 0/2] Replace PID bitmap allocation with IDR API

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
   3301        304          0       3605        e15    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
   2870        216         16       3102        c1e    kernel/pid_namespace.o

There wasn't a considerable difference between the time required for
allocation of PIDs to the processes.

---
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                              | 239 +++++-------------------------
 kernel/pid_namespace.c                    |  54 +++----
 9 files changed, 68 insertions(+), 255 deletions(-)

-- 
2.7.4