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authorOleg Nesterov <oleg@tv-sign.ru>2006-03-28 19:11:07 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-28 21:36:41 -0500
commit73b9ebfe126a4a886ee46cbab637374d7024668a (patch)
treed7ba00d4ce76b49c1569334956cd196b35977a04 /include/linux
parentc97d98931ac52ef110b62d9b75c6a6f2bfbc1898 (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 'include/linux')
-rw-r--r--include/linux/sched.h2
1 files changed, 0 insertions, 2 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 1f16fb1fea22..ddc0df7f8bf5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1214,8 +1214,6 @@ static inline int thread_group_empty(task_t *p)
1214#define delay_group_leader(p) \ 1214#define delay_group_leader(p) \
1215 (thread_group_leader(p) && !thread_group_empty(p)) 1215 (thread_group_leader(p) && !thread_group_empty(p))
1216 1216
1217extern void unhash_process(struct task_struct *p);
1218
1219/* 1217/*
1220 * Protects ->fs, ->files, ->mm, ->ptrace, ->group_info, ->comm, keyring 1218 * Protects ->fs, ->files, ->mm, ->ptrace, ->group_info, ->comm, keyring
1221 * subscriptions and synchronises with wait4(). Also used in procfs. Also 1219 * subscriptions and synchronises with wait4(). Also used in procfs. Also