Date: Thu, 17 Nov 2011 11:47:42 +0200 From: Andriy Gapon <avg@FreeBSD.org> To: Kostik Belousov <kostikbel@gmail.com> Cc: Alexander Motin <mav@FreeBSD.org>, freebsd-current@FreeBSD.org Subject: Re: Stop scheduler on panic Message-ID: <4EC4D83E.3090307@FreeBSD.org> In-Reply-To: <4EC4C712.8040701@FreeBSD.org> References: <20111113083215.GV50300@deviant.kiev.zoral.com.ua> <20111116202714.5ee4bd53@fabiankeil.de> <4EC43764.1020202@FreeBSD.org> <4EC4423A.3020904@FreeBSD.org> <20111117081533.GP50300@deviant.kiev.zoral.com.ua> <4EC4C712.8040701@FreeBSD.org>
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on 17/11/2011 10:34 Andriy Gapon said the following:
> on 17/11/2011 10:15 Kostik Belousov said the following:
>> I have the following change for eons on my test boxes. Without it,
>> I simply cannot get _any_ dump.
>>
>> diff --git a/sys/cam/cam_xpt.c b/sys/cam/cam_xpt.c
>> index 10b89c7..a38e42f 100644
>> --- a/sys/cam/cam_xpt.c
>> +++ b/sys/cam/cam_xpt.c
>> @@ -4230,7 +4230,7 @@ xpt_done(union ccb *done_ccb)
>> TAILQ_INSERT_TAIL(&cam_simq, sim, links);
>> mtx_unlock(&cam_simq_lock);
>> sim->flags |= CAM_SIM_ON_DONEQ;
>> - if (first)
>> + if (first && panicstr == NULL)
>> swi_sched(cambio_ih, 0);
>> }
>> }
>
> I think that this (or similar) change should go into the patch and the tree.
>
And, BTW, I still would like to do something like the following (perhaps with
td_oncpu = NOCPU and td_flags &= ~TDF_NEEDRESCHED also moved to the common code):
Index: sys/kern/sched_ule.c
===================================================================
--- sys/kern/sched_ule.c (revision 227608)
+++ sys/kern/sched_ule.c (working copy)
@@ -1790,7 +1790,6 @@ sched_switch(struct thread *td, struct thread *new
td->td_oncpu = NOCPU;
if (!(flags & SW_PREEMPT))
td->td_flags &= ~TDF_NEEDRESCHED;
- td->td_owepreempt = 0;
tdq->tdq_switchcnt++;
/*
* The lock pointer in an idle thread should never change. Reset it
Index: sys/kern/kern_synch.c
===================================================================
--- sys/kern/kern_synch.c (revision 227608)
+++ sys/kern/kern_synch.c (working copy)
@@ -406,6 +406,8 @@ mi_switch(int flags, struct thread *newtd)
("mi_switch: switch must be voluntary or involuntary"));
KASSERT(newtd != curthread, ("mi_switch: preempting back to ourself"));
+ td->td_owepreempt = 0;
+
/*
* Don't perform context switches from the debugger.
*/
Index: sys/kern/sched_4bsd.c
===================================================================
--- sys/kern/sched_4bsd.c (revision 227608)
+++ sys/kern/sched_4bsd.c (working copy)
@@ -940,7 +940,6 @@ sched_switch(struct thread *td, struct thread *new
td->td_lastcpu = td->td_oncpu;
if (!(flags & SW_PREEMPT))
td->td_flags &= ~TDF_NEEDRESCHED;
- td->td_owepreempt = 0;
td->td_oncpu = NOCPU;
/*
Does anybody see any potential problems with such a change?
--
Andriy Gapon
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