- Move rusage from being per-process in struct pstats to per-thread in

   td_ru.  This removes the requirement for per-process synchronization in
   statclock() and mi_switch().  This was previously supported by
   sched_lock which is going away.  All modifications to rusage are now
   done in the context of the owning thread.  reads proceed without locks.
 - Aggregate exiting threads rusage in thread_exit() such that the exiting
   thread's rusage is not lost.
 - Provide a new routine, rufetch() to fetch an aggregate of all rusage
   structures from all threads in a process.  This routine must be used
   in any place requiring a rusage from a process prior to it's exit.  The
   exited process's rusage is still available via p_ru.
 - Aggregate tick statistics only on demand via rufetch() or when a thread
   exits.  Tick statistics are kept in the thread and protected by sched_lock
   until it exits.

Initial patch by:	attilio
Reviewed by:		attilio, bde (some objections), arch (mostly silent)

1 files changed, 2 insertions, 18 deletions

diff --git a/sys/kern/subr_trap.c b/sys/kern/subr_trap.c
index 15c8fdd..e9d9c35 100644
--- a/sys/kern/subr_trap.c
+++ b/sys/kern/subr_trap.c
@@ -147,7 +147,6 @@ ast(struct trapframe *framep)
 {
 	struct thread *td;
 	struct proc *p;
-	struct rlimit rlim;
 	int sflag;
 	int flags;
 	int sig;
@@ -183,8 +182,8 @@ ast(struct trapframe *framep)
 	mtx_lock_spin(&sched_lock);
 	flags = td->td_flags;
 	sflag = p->p_sflag;
-	if (p->p_sflag & (PS_ALRMPEND | PS_PROFPEND | PS_XCPU))
-		p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND | PS_XCPU);
+	if (p->p_sflag & (PS_ALRMPEND | PS_PROFPEND))
+		p->p_sflag &= ~(PS_ALRMPEND | PS_PROFPEND);
 #ifdef MAC
 	if (p->p_sflag & PS_MACPEND)
 		p->p_sflag &= ~PS_MACPEND;
@@ -231,21 +230,6 @@ ast(struct trapframe *framep)
 		psignal(p, SIGPROF);
 		PROC_UNLOCK(p);
 	}
-	if (sflag & PS_XCPU) {
-		PROC_LOCK(p);
-		lim_rlimit(p, RLIMIT_CPU, &rlim);
-		mtx_lock_spin(&sched_lock);
-		if (p->p_rux.rux_runtime >= rlim.rlim_max * cpu_tickrate()) {
-			mtx_unlock_spin(&sched_lock);
-			killproc(p, "exceeded maximum CPU limit");
-		} else {
-			if (p->p_cpulimit < rlim.rlim_max)
-				p->p_cpulimit += 5;
-			mtx_unlock_spin(&sched_lock);
-			psignal(p, SIGXCPU);
-		}
-		PROC_UNLOCK(p);
-	}
 #ifdef MAC
 	if (sflag & PS_MACPEND)
 		mac_thread_userret(td);