T23 -CURRENT question...

[Doug White]

On Sun, 21 Dec 2003, Tony Saign wrote:

> After my laptop is running for several days I sometimes receive the
> below in dmesg...Nothing seems to trigger it?

> lock order reversal

This is telling you about a design problem with the referenced functions.
The WITNESS system keeps track of lock usage and ensures that locks are
freed in the reverse order in which they are acquired.  You can remove
'options WITNESS' from your kernel if you want them to go away. As a
bonus, disabling WITNESS can give you a 50-100% performance boost.

Typically, though, LORs should be reported to -current if they are new and
not previously reported.

>  1st 0xc7480dec vm object (vm_object) @
> /usr/src/sys/vm/swap_pager.c:1323
>  2nd 0xc07a89a0 swap_pager swhash (swap_pager swash) @
> /usr/src/vm/swap_pager.c:1838
>  3rd 0xc1036948 vm object (vm object) @ /usr/src/sys/vm/uma_core.c:881

I believe this is one of the known cases.

-- 
Doug White                    |  FreeBSD: The Power to Serve
dwhite at gumbysoft.com          |  www.FreeBSD.org