Date: Wed, 21 Dec 2016 14:40:09 +0800 From: Julian Elischer <julian@freebsd.org> To: John Baldwin <jhb@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r310336 - head/sys/kern Message-ID: <d3bc46ff-7ecb-703c-4a0a-ebf5c31682e5@freebsd.org> In-Reply-To: <201612201944.uBKJiiMg034231@repo.freebsd.org> References: <201612201944.uBKJiiMg034231@repo.freebsd.org>
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On 21/12/2016 3:44 AM, John Baldwin wrote: > Author: jhb > Date: Tue Dec 20 19:44:44 2016 > New Revision: 310336 > URL: https://svnweb.freebsd.org/changeset/base/310336 > > Log: > Don't spin in pause() during early boot for kthreads other than thread0. > > pause() uses a spin loop to simulate a sleep during early boot. However, > we only need this for thread0 to get far enough in the boot process to > enable timers (at which point pause() can sleep). For other kthreads, > sleeping in pause() is ok as the callout will be scheduled and will > eventually fire once thread0 initializes timers. maybe we just need to depend on a variable "have_timers" that is independent of the cold/hot/whatever settings. first code to enable a timer sets it. > > Tested by: Steven Kargl > Sleuthing by: markj > MFC after: 1 week > Sponsored by: Netflix > > Modified: > head/sys/kern/kern_synch.c > > Modified: head/sys/kern/kern_synch.c > ============================================================================== > --- head/sys/kern/kern_synch.c Tue Dec 20 19:30:21 2016 (r310335) > +++ head/sys/kern/kern_synch.c Tue Dec 20 19:44:44 2016 (r310336) > @@ -321,7 +321,8 @@ pause_sbt(const char *wmesg, sbintime_t > if (sbt == 0) > sbt = tick_sbt; > > - if (cold || kdb_active || SCHEDULER_STOPPED()) { > + if ((cold && curthread == &thread0) || kdb_active || > + SCHEDULER_STOPPED()) { > /* > * We delay one second at a time to avoid overflowing the > * system specific DELAY() function(s): > >
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