diff options
| author | Oleg Nesterov <oleg@tv-sign.ru> | 2006-03-28 16:11:07 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-03-28 18:36:41 -0800 |
| commit | 73b9ebfe126a4a886ee46cbab637374d7024668a (patch) | |
| tree | d7ba00d4ce76b49c1569334956cd196b35977a04 /kernel/fork.c | |
| parent | c97d98931ac52ef110b62d9b75c6a6f2bfbc1898 (diff) | |
[PATCH] pidhash: don't count idle threads
fork_idle() does unhash_process() just after copy_process(). Contrary,
boot_cpu's idle thread explicitely registers itself for each pid_type with nr
= 0.
copy_process() already checks p->pid != 0 before process_counts++, I think we
can just skip attach_pid() calls and job control inits for idle threads and
kill unhash_process(). We don't need to cleanup ->proc_dentry in fork_idle()
because with this patch idle threads are never hashed in
kernel/pid.c:pid_hash[].
We don't need to hash pid == 0 in pidmap_init(). free_pidmap() is never
called with pid == 0 arg, so it will never be reused. So it is still possible
to use pid == 0 in any PIDTYPE_xxx namespace from kernel/pid.c's POV.
However with this patch we don't hash pid == 0 for PIDTYPE_PID case. We still
have have PIDTYPE_PGID/PIDTYPE_SID entries with pid == 0: /sbin/init and
kernel threads which don't call daemonize().
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 35 |
1 files changed, 18 insertions, 17 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 74c67629ee6..0c32e28cdc5 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1181,25 +1181,26 @@ static task_t *copy_process(unsigned long clone_flags, */ p->ioprio = current->ioprio; - add_parent(p); - if (unlikely(p->ptrace & PT_PTRACED)) - __ptrace_link(p, current->parent); - - if (thread_group_leader(p)) { - p->signal->tty = current->signal->tty; - p->signal->pgrp = process_group(current); - p->signal->session = current->signal->session; - attach_pid(p, PIDTYPE_PGID, process_group(p)); - attach_pid(p, PIDTYPE_SID, p->signal->session); - - list_add_tail(&p->tasks, &init_task.tasks); - if (p->pid) + if (likely(p->pid)) { + add_parent(p); + if (unlikely(p->ptrace & PT_PTRACED)) + __ptrace_link(p, current->parent); + + if (thread_group_leader(p)) { + p->signal->tty = current->signal->tty; + p->signal->pgrp = process_group(current); + p->signal->session = current->signal->session; + attach_pid(p, PIDTYPE_PGID, process_group(p)); + attach_pid(p, PIDTYPE_SID, p->signal->session); + + list_add_tail(&p->tasks, &init_task.tasks); __get_cpu_var(process_counts)++; + } + attach_pid(p, PIDTYPE_TGID, p->tgid); + attach_pid(p, PIDTYPE_PID, p->pid); + nr_threads++; } - attach_pid(p, PIDTYPE_TGID, p->tgid); - attach_pid(p, PIDTYPE_PID, p->pid); - nr_threads++; total_forks++; spin_unlock(¤t->sighand->siglock); write_unlock_irq(&tasklist_lock); @@ -1263,7 +1264,7 @@ task_t * __devinit fork_idle(int cpu) if (!task) return ERR_PTR(-ENOMEM); init_idle(task, cpu); - unhash_process(task); + return task; } |