svn commit: r193723 - head/sys/kern
Robert Watson
rwatson at FreeBSD.org
Mon Jun 8 15:26:11 UTC 2009
Author: rwatson
Date: Mon Jun 8 15:26:09 2009
New Revision: 193723
URL: http://svn.freebsd.org/changeset/base/193723
Log:
Move zombie-reaping code out of kern_wait() and into its own function,
proc_reap().
Reviewed by: jhb
MFC after: 3 days
Sponsored by: Google, Inc.
Modified:
head/sys/kern/kern_exit.c
Modified: head/sys/kern/kern_exit.c
==============================================================================
--- head/sys/kern/kern_exit.c Mon Jun 8 15:17:36 2009 (r193722)
+++ head/sys/kern/kern_exit.c Mon Jun 8 15:26:09 2009 (r193723)
@@ -682,11 +682,130 @@ wait4(struct thread *td, struct wait_arg
return (error);
}
+/*
+ * Reap the remains of a zombie process and optionally return status and
+ * rusage. Asserts and will release both the proctree_lock and the process
+ * lock as part of its work.
+ */
+static void
+proc_reap(struct thread *td, struct proc *p, int *status, int options,
+ struct rusage *rusage)
+{
+ INIT_VPROCG(P_TO_VPROCG(p));
+ struct proc *q, *t;
+
+ sx_assert(&proctree_lock, SA_XLOCKED);
+ PROC_LOCK_ASSERT(p, MA_OWNED);
+ PROC_SLOCK_ASSERT(p, MA_OWNED);
+ KASSERT(p->p_state == PRS_ZOMBIE, ("proc_reap: !PRS_ZOMBIE"));
+
+ q = td->td_proc;
+ if (rusage) {
+ *rusage = p->p_ru;
+ calcru(p, &rusage->ru_utime, &rusage->ru_stime);
+ }
+ PROC_SUNLOCK(p);
+ td->td_retval[0] = p->p_pid;
+ if (status)
+ *status = p->p_xstat; /* convert to int */
+ if (options & WNOWAIT) {
+ /*
+ * Only poll, returning the status. Caller does not wish to
+ * release the proc struct just yet.
+ */
+ PROC_UNLOCK(p);
+ sx_xunlock(&proctree_lock);
+ return;
+ }
+
+ PROC_LOCK(q);
+ sigqueue_take(p->p_ksi);
+ PROC_UNLOCK(q);
+ PROC_UNLOCK(p);
+
+ /*
+ * If we got the child via a ptrace 'attach', we need to give it back
+ * to the old parent.
+ */
+ if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
+ PROC_LOCK(p);
+ p->p_oppid = 0;
+ proc_reparent(p, t);
+ PROC_UNLOCK(p);
+ tdsignal(t, NULL, SIGCHLD, p->p_ksi);
+ wakeup(t);
+ cv_broadcast(&p->p_pwait);
+ PROC_UNLOCK(t);
+ sx_xunlock(&proctree_lock);
+ return;
+ }
+
+ /*
+ * Remove other references to this process to ensure we have an
+ * exclusive reference.
+ */
+ sx_xlock(&allproc_lock);
+ LIST_REMOVE(p, p_list); /* off zombproc */
+ sx_xunlock(&allproc_lock);
+ LIST_REMOVE(p, p_sibling);
+ leavepgrp(p);
+ sx_xunlock(&proctree_lock);
+
+ /*
+ * As a side effect of this lock, we know that all other writes to
+ * this proc are visible now, so no more locking is needed for p.
+ */
+ PROC_LOCK(p);
+ p->p_xstat = 0; /* XXX: why? */
+ PROC_UNLOCK(p);
+ PROC_LOCK(q);
+ ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru, &p->p_rux);
+ PROC_UNLOCK(q);
+
+ /*
+ * Decrement the count of procs running with this uid.
+ */
+ (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
+
+ /*
+ * Free credentials, arguments, and sigacts.
+ */
+ crfree(p->p_ucred);
+ p->p_ucred = NULL;
+ pargs_drop(p->p_args);
+ p->p_args = NULL;
+ sigacts_free(p->p_sigacts);
+ p->p_sigacts = NULL;
+
+ /*
+ * Do any thread-system specific cleanups.
+ */
+ thread_wait(p);
+
+ /*
+ * Give vm and machine-dependent layer a chance to free anything that
+ * cpu_exit couldn't release while still running in process context.
+ */
+ vm_waitproc(p);
+#ifdef MAC
+ mac_proc_destroy(p);
+#endif
+ KASSERT(FIRST_THREAD_IN_PROC(p),
+ ("proc_reap: no residual thread!"));
+ uma_zfree(proc_zone, p);
+ sx_xlock(&allproc_lock);
+ nprocs--;
+#ifdef VIMAGE
+ vprocg->nprocs--;
+#endif
+ sx_xunlock(&allproc_lock);
+}
+
int
kern_wait(struct thread *td, pid_t pid, int *status, int options,
struct rusage *rusage)
{
- struct proc *p, *q, *t;
+ struct proc *p, *q;
int error, nfound;
AUDIT_ARG(pid, pid);
@@ -736,111 +855,7 @@ loop:
nfound++;
PROC_SLOCK(p);
if (p->p_state == PRS_ZOMBIE) {
- INIT_VPROCG(P_TO_VPROCG(p));
- if (rusage) {
- *rusage = p->p_ru;
- calcru(p, &rusage->ru_utime, &rusage->ru_stime);
- }
- PROC_SUNLOCK(p);
- td->td_retval[0] = p->p_pid;
- if (status)
- *status = p->p_xstat; /* convert to int */
- if (options & WNOWAIT) {
-
- /*
- * Only poll, returning the status.
- * Caller does not wish to release the proc
- * struct just yet.
- */
- PROC_UNLOCK(p);
- sx_xunlock(&proctree_lock);
- return (0);
- }
-
- PROC_LOCK(q);
- sigqueue_take(p->p_ksi);
- PROC_UNLOCK(q);
- PROC_UNLOCK(p);
-
- /*
- * If we got the child via a ptrace 'attach',
- * we need to give it back to the old parent.
- */
- if (p->p_oppid && (t = pfind(p->p_oppid)) != NULL) {
- PROC_LOCK(p);
- p->p_oppid = 0;
- proc_reparent(p, t);
- PROC_UNLOCK(p);
- tdsignal(t, NULL, SIGCHLD, p->p_ksi);
- wakeup(t);
- cv_broadcast(&p->p_pwait);
- PROC_UNLOCK(t);
- sx_xunlock(&proctree_lock);
- return (0);
- }
-
- /*
- * Remove other references to this process to ensure
- * we have an exclusive reference.
- */
- sx_xlock(&allproc_lock);
- LIST_REMOVE(p, p_list); /* off zombproc */
- sx_xunlock(&allproc_lock);
- LIST_REMOVE(p, p_sibling);
- leavepgrp(p);
- sx_xunlock(&proctree_lock);
-
- /*
- * As a side effect of this lock, we know that
- * all other writes to this proc are visible now, so
- * no more locking is needed for p.
- */
- PROC_LOCK(p);
- p->p_xstat = 0; /* XXX: why? */
- PROC_UNLOCK(p);
- PROC_LOCK(q);
- ruadd(&q->p_stats->p_cru, &q->p_crux, &p->p_ru,
- &p->p_rux);
- PROC_UNLOCK(q);
-
- /*
- * Decrement the count of procs running with this uid.
- */
- (void)chgproccnt(p->p_ucred->cr_ruidinfo, -1, 0);
-
- /*
- * Free credentials, arguments, and sigacts.
- */
- crfree(p->p_ucred);
- p->p_ucred = NULL;
- pargs_drop(p->p_args);
- p->p_args = NULL;
- sigacts_free(p->p_sigacts);
- p->p_sigacts = NULL;
-
- /*
- * Do any thread-system specific cleanups.
- */
- thread_wait(p);
-
- /*
- * Give vm and machine-dependent layer a chance
- * to free anything that cpu_exit couldn't
- * release while still running in process context.
- */
- vm_waitproc(p);
-#ifdef MAC
- mac_proc_destroy(p);
-#endif
- KASSERT(FIRST_THREAD_IN_PROC(p),
- ("kern_wait: no residual thread!"));
- uma_zfree(proc_zone, p);
- sx_xlock(&allproc_lock);
- nprocs--;
-#ifdef VIMAGE
- vprocg->nprocs--;
-#endif
- sx_xunlock(&allproc_lock);
+ proc_reap(td, p, status, options, rusage);
return (0);
}
if ((p->p_flag & P_STOPPED_SIG) &&
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