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- Move sched_fork() later in fork() after the various sections of the new

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thread and proc have been copied and zeroed from the old thread and
  proc.  Otherwise attempts to modify thread or process data in sched_fork()
  could be undone.
- Don't copy td_{base,}_user_pri from the old thread to the new thread in
  sched_fork_thread() in ULE.  This is already done courtesy the bcopy()
  of the thread copy region.
- Always initialize the real priority (td_priority) of new threads to the
  new thread's base priority (td_base_pri) to avoid bogusly inheriting a
  borrowed priority from the parent thread.

MFC after:	2 weeks
This commit is contained in:
John Baldwin 2011-01-06 22:24:00 +00:00
parent 177499ebcc
commit 22d19207e9
3 changed files with 13 additions and 9 deletions

13
sys/kern/kern_fork.c

@ -360,12 +360,6 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
p2->p_state = PRS_NEW; /* protect against others */
p2->p_pid = trypid;
/*
* Allow the scheduler to initialize the child.
*/
thread_lock(td);
sched_fork(td, td2);
thread_unlock(td);
AUDIT_ARG_PID(p2->p_pid);
LIST_INSERT_HEAD(&allproc, p2, p_list);
LIST_INSERT_HEAD(PIDHASH(p2->p_pid), p2, p_hash);
@ -456,6 +450,13 @@ do_fork(struct thread *td, int flags, struct proc *p2, struct thread *td2,
td2->td_vnet_lpush = NULL;
#endif
/*
* Allow the scheduler to initialize the child.
*/
thread_lock(td);
sched_fork(td, td2);
thread_unlock(td);
/*
* Duplicate sub-structures as needed.
* Increase reference counts on shared objects.

1
sys/kern/sched_4bsd.c

@ -759,6 +759,7 @@ sched_fork_thread(struct thread *td, struct thread *childtd)
childtd->td_estcpu = td->td_estcpu;
childtd->td_lock = &sched_lock;
childtd->td_cpuset = cpuset_ref(td->td_cpuset);
childtd->td_priority = childtd->td_base_pri;
ts = childtd->td_sched;
bzero(ts, sizeof(*ts));
ts->ts_flags |= (td->td_sched->ts_flags & TSF_AFFINITY);

8
sys/kern/sched_ule.c

@ -1961,14 +1961,16 @@ sched_fork_thread(struct thread *td, struct thread *child)
ts2->ts_cpu = ts->ts_cpu;
ts2->ts_flags = 0;
/*
* Grab our parents cpu estimation information and priority.
* Grab our parents cpu estimation information.
*/
ts2->ts_ticks = ts->ts_ticks;
ts2->ts_ltick = ts->ts_ltick;
ts2->ts_incrtick = ts->ts_incrtick;
ts2->ts_ftick = ts->ts_ftick;
child->td_user_pri = td->td_user_pri;
child->td_base_user_pri = td->td_base_user_pri;
/*
* Do not inherit any borrowed priority from the parent.
*/
child->td_priority = child->td_base_pri;
/*
* And update interactivity score.
*/