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| author |   Eric W. Biederman <ebiederm@xmission.com> | 2006-09-27 01:51:06 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@g5.osdl.org> | 2006-09-27 08:26:19 -0700 |
| commit | c18258c6f0848f97e85287f6271c511a092bb784 (patch) | |
| tree | 16c057a171b7623895ee208459392c1104193b84 /include/linux/pid.h | |
| parent | [PATCH] sysctl: Document that sys_sysctl will be removed (diff) | |
| download | linux-dev-c18258c6f0848f97e85287f6271c511a092bb784.tar.xz linux-dev-c18258c6f0848f97e85287f6271c511a092bb784.zip | |
[PATCH] pid: Implement transfer_pid and use it to simplify de_thread
In de_thread we move pids from one process to another, a rather ugly case.
The function transfer_pid makes it clear what we are doing, and makes the
action atomic. This is useful we ever want to atomically traverse the
process group and session lists, in a rcu safe manner.
Even if the atomic properties this change should be a win as transfer_pid
should be less code to execute than executing both attach_pid and
detach_pid, and this should make de_thread slightly smaller as only a
single function call needs to be emitted. The only downside is that the
code might be slower to execute as the odds are against transfer_pid being
in cache.
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux/pid.h')
| -rw-r--r-- | include/linux/pid.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/pid.h b/include/linux/pid.h index 29960b03bef7..93da7e2d9f30 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -76,6 +76,8 @@ extern int FASTCALL(attach_pid(struct task_struct *task, enum pid_type type, int nr)); extern void FASTCALL(detach_pid(struct task_struct *task, enum pid_type)); +extern void FASTCALL(transfer_pid(struct task_struct *old, + struct task_struct *new, enum pid_type)); /* * look up a PID in the hash table. Must be called with the tasklist_lock |