Date: Tue, 2 Jan 2018 00:14:46 +0000 (UTC) From: Mateusz Guzik <mjg@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-11@freebsd.org Subject: svn commit: r327481 - stable/11/sys/kern Message-ID: <201801020014.w020EkU3029916@repo.freebsd.org>
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Author: mjg Date: Tue Jan 2 00:14:46 2018 New Revision: 327481 URL: https://svnweb.freebsd.org/changeset/base/327481 Log: MFC r325924: sched: move panic handling code out of choosethread This avoids jumps in the common case of the kernel not being panicked. Modified: stable/11/sys/kern/kern_switch.c Directory Properties: stable/11/ (props changed) Modified: stable/11/sys/kern/kern_switch.c ============================================================================== --- stable/11/sys/kern/kern_switch.c Tue Jan 2 00:11:56 2018 (r327480) +++ stable/11/sys/kern/kern_switch.c Tue Jan 2 00:14:46 2018 (r327481) @@ -150,24 +150,37 @@ SYSCTL_PROC(_kern_sched_stats, OID_AUTO, reset, CTLTYP /* * Select the thread that will be run next. */ -struct thread * -choosethread(void) + +static __noinline struct thread * +choosethread_panic(struct thread *td) { - struct thread *td; -retry: - td = sched_choose(); - /* * If we are in panic, only allow system threads, * plus the one we are running in, to be run. */ - if (panicstr && ((td->td_proc->p_flag & P_SYSTEM) == 0 && +retry: + if (((td->td_proc->p_flag & P_SYSTEM) == 0 && (td->td_flags & TDF_INPANIC) == 0)) { /* note that it is no longer on the run queue */ TD_SET_CAN_RUN(td); + td = sched_choose(); goto retry; } + + TD_SET_RUNNING(td); + return (td); +} + +struct thread * +choosethread(void) +{ + struct thread *td; + + td = sched_choose(); + + if (__predict_false(panicstr != NULL)) + return (choosethread_panic(td)); TD_SET_RUNNING(td); return (td);
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