Date: Fri, 14 Mar 2008 02:56:25 GMT From: Peter Wemm <peter@FreeBSD.org> To: Perforce Change Reviews <perforce@freebsd.org> Subject: PERFORCE change 137665 for review Message-ID: <200803140256.m2E2uPUo075018@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=137665 Change 137665 by peter@peter_overcee on 2008/03/14 02:56:09 Sigh. sched_userret() diverged. Affected files ... .. //depot/projects/bike_sched/sys/kern/sched_4bsd.c#21 edit .. //depot/projects/bike_sched/sys/kern/sched_ule.c#21 edit .. //depot/projects/bike_sched/sys/kern/subr_trap.c#8 edit Differences ... ==== //depot/projects/bike_sched/sys/kern/sched_4bsd.c#21 (text+ko) ==== @@ -1246,7 +1246,6 @@ thread_unlock(td); } -/* XXX removed */ void sched_userret(struct thread *td) { ==== //depot/projects/bike_sched/sys/kern/sched_ule.c#21 (text+ko) ==== @@ -2023,9 +2023,28 @@ thread_unlock(td); } -MISMERGE! -p4 - you suck! /* + * Fix priorities on return to user-space. Priorities may be elevated due + * to static priorities in msleep() or similar. + */ +void +sched_userret(struct thread *td) +{ + /* + * XXX we cheat slightly on the locking here to avoid locking in + * the usual case. Setting td_priority here is essentially an + * incomplete workaround for not setting it properly elsewhere. + * Now that some interrupt handlers are threads, not setting it + * properly elsewhere can clobber it in the window between setting + * it here and returning to user mode, so don't waste time setting + * it perfectly here. + */ + KASSERT((td->td_flags & TDF_BORROWING) == 0, + ("thread with borrowed priority returning to userland")); + if (td->td_priority != td->td_user_pri) { + thread_lock(td); + td->td_priority = td->td_user_pri; + td->td_base_pri = td->td_user_pri; tdq_setlowpri(TDQ_SELF(), td); thread_unlock(td); } ==== //depot/projects/bike_sched/sys/kern/subr_trap.c#8 (text+ko) ==== @@ -124,26 +124,11 @@ */ if (p->p_flag & P_PROFIL) addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio); + /* - * Fix priorities on return to user-space. Priorities may be elevated due - * to static priorities in msleep() or similar. - * - * XXX we cheat slightly on the locking here to avoid locking in - * the usual case. Setting td_priority here is essentially an - * incomplete workaround for not setting it properly elsewhere. - * Now that some interrupt handlers are threads, not setting it - * properly elsewhere can clobber it in the window between setting - * it here and returning to user mode, so don't waste time setting - * it perfectly here. + * Let the scheduler adjust our priority etc. */ - KASSERT((td->td_flags & TDF_BORROWING) == 0, - ("userret: thread with borrowed priority returning to userland")); - if (td->td_priority != td->td_user_pri) { - thread_lock(td); - td->td_priority = td->td_user_pri; - td->td_base_pri = td->td_user_pri; - thread_unlock(td); - } + sched_userret(td); KASSERT(td->td_locks == 0, ("userret: Returning with %d locks held.", td->td_locks)); }
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