Re: [patch] Real-Time Preemption, -RT-2.6.12-rc1-V0.7.41-07

Ingo Molnar
2005-03-31T11:03:50Z

* Steven Rostedt <rostedt@goodmis.org> wrote:

> Well, here it finally is. There's still things I don't like about it.
> But it seems to work, and that's the important part.
>
> I had to reluctantly add two items to the task_struct. I was hoping
> to avoid that. But because of race conditions it seemed to be the only
> way.

well it's not a big problem, and we avoided having to add flags to the
rt_lock structure, which is the important issue.

your patch looks good, i've added it to my tree and have uploaded the
-26-00 patch. It boots fine on my testbox, except for some new messages:

knodemgrd_0/902: BUG in __down_complete at kernel/rt.c:1568
[<c0103956>] dump_stack+0x23/0x25 (20)
[<c0130dcd>] down_trylock+0x1fb/0x200 (48)
[<c0364ee2>] nodemgr_host_thread+0xd0/0x17b (48)
[<c0100d4d>] kernel_thread_helper+0x5/0xb (136249364)
---------------------------
| preempt count: 00000001 ]
| 1-level deep critical section nesting:
----------------------------------------
.. [<c0133a75>] .... print_traces+0x1b/0x52
.....[<c0103956>] .. ( <= dump_stack+0x23/0x25)

this goes away if i revert your patch. It seems the reason is that
trylock hasnt been updated to use the pending-owner logic?

Ingo