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Postpone sx_sunlock(&proctree_lock) on fork until after allproc is dropped.

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There is a significant contention on the lock during -j 128 package build.
This change drops total wait time on this lock by 60%.
This commit is contained in:
Mateusz Guzik 2018-02-17 00:23:28 +00:00
parent 6776bfeb8f
commit 65f29b9caa
1 changed files with 2 additions and 3 deletions
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5
sys/kern/kern_fork.c
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@ -401,8 +401,6 @@ do_fork(struct thread *td, struct fork_req *fr, struct proc *p2, struct thread *
trypid = fork_findpid(fr->fr_flags);
sx_sunlock(&proctree_lock);
p2->p_state = PRS_NEW; /* protect against others */
p2->p_pid = trypid;
AUDIT_ARG_PID(p2->p_pid);
@ -414,6 +412,7 @@ do_fork(struct thread *td, struct fork_req *fr, struct proc *p2, struct thread *
PROC_LOCK(p1);
sx_xunlock(&allproc_lock);
sx_sunlock(&proctree_lock);
bcopy(&p1->p_startcopy, &p2->p_startcopy,
__rangeof(struct proc, p_startcopy, p_endcopy));
@ -977,8 +976,8 @@ fork1(struct thread *td, struct fork_req *fr)
}
error = EAGAIN;
sx_sunlock(&proctree_lock);
sx_xunlock(&allproc_lock);
sx_sunlock(&proctree_lock);
#ifdef MAC
mac_proc_destroy(newproc);
#endif