Date: Fri, 5 Oct 2007 12:59:10 GMT From: Marko Zec <zec@FreeBSD.org> To: Perforce Change Reviews <perforce@FreeBSD.org> Subject: PERFORCE change 127226 for review Message-ID: <200710051259.l95CxAAh006372@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=127226 Change 127226 by zec@zec_tpx32 on 2007/10/05 12:58:54 When a process is exiting there is a short window while the proc is still schedulable but it doesn't have an ucred associated with it any more. Hence, inside the scheduler if p->p_ucred is not available, we supply a dummy loadavg value for purposes of priority recalculation, given that the process should be gone anyhow in a few microseconds, so inaccurate priority calculation shouldn't be a problem in this case. In short, with this change maintaining per-vprocg load average accounting should finally work OK, at least with SCHED_4BSD. Affected files ... .. //depot/projects/vimage/src/sys/kern/sched_4bsd.c#12 edit Differences ... ==== //depot/projects/vimage/src/sys/kern/sched_4bsd.c#12 (text+ko) ==== @@ -389,24 +389,25 @@ static void schedcpu(void) { -#ifndef VIMAGE - register fixpt_t loadfac = loadfactor(averunnable.ldavg[0]); -#endif + register fixpt_t loadfac; struct thread *td; struct proc *p; struct td_sched *ts; int awake, realstathz; +#ifndef VIMAGE + loadfac = loadfactor(averunnable.ldavg[0]); +#endif realstathz = stathz ? stathz : hz; sx_slock(&allproc_lock); FOREACH_PROC_IN_SYSTEM(p) { PROC_SLOCK(p); #ifdef VIMAGE - KASSERT((p->p_ucred != NULL), ("p_ucred")); - KASSERT((p->p_ucred->cr_vimage != NULL), ("cr_vimage")); - KASSERT((p->p_ucred->cr_vimage->v_procg != NULL), ("v_procg")); - INIT_VPROCG(p->p_ucred->cr_vimage->v_procg); - fixpt_t loadfac = loadfactor(V_averunnable.ldavg[0]); + if (p->p_ucred != NULL) { + INIT_VPROCG(p->p_ucred->cr_vimage->v_procg); + loadfac = loadfactor(V_averunnable.ldavg[0]); + } else + loadfac = 0; #endif FOREACH_THREAD_IN_PROC(p, td) { awake = 0;
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