Session space issues

NTDEV
1

Hi everyone,

In the context of our system, we are using 8 virtual display drivers (rendering to shared memory files) and 3 physical displays.
For this purpose we had to extend the session space size to 240 instead of regular 48.
But still we observed randomly attaching/detaching display issues.
Having understood the way windows attach/detach a monitor (virtual or not) we are now clueless when we randomly observe a file mapping error when all the displays are trying to be attached on the desktop.

Could someone explain me how to monitor my session space, as the live kernel debugging does not give me enough information as well as diving into the complete dump of the system…

I would really appreciate some help on this part.

Regards,
Maxime

2

Well, you might check for address space exhaustion via !session to set the session context, then !address. (You’ll have to use an old WinDbg, as !address is *still* broken in the latest release.)

  • S

-----Original Message-----
From: xxxxx@lists.osr.com [mailto:xxxxx@lists.osr.com] On Behalf Of xxxxx@yahoo.fr
Sent: Tuesday, November 04, 2008 8:57 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] Session space issues

Hi everyone,

In the context of our system, we are using 8 virtual display drivers (rendering to shared memory files) and 3 physical displays.
For this purpose we had to extend the session space size to 240 instead of regular 48.
But still we observed randomly attaching/detaching display issues.
Having understood the way windows attach/detach a monitor (virtual or not) we are now clueless when we randomly observe a file mapping error when all the displays are trying to be attached on the desktop.

Could someone explain me how to monitor my session space, as the live kernel debugging does not give me enough information as well as diving into the complete dump of the system…

I would really appreciate some help on this part.

Regards,
Maxime

NTDEV is sponsored by OSR

For our schedule of WDF, WDM, debugging and other seminars visit:
http://www.osr.com/seminars

To unsubscribe, visit the List Server section of OSR Online at http://www.osronline.com/page.cfm?name=ListServer

3

Thx Ken, i ll look into that!

Regards,
Max

4

> Well, you might check for address space exhaustion via !session

to set the session context, then !address. (You’ll have to use an
old WinDbg, as !address is *still* broken in the latest release.)

I could be wrong, but I believe that kernel mode !address is currently
broken on Vista+, regardless of debugger version (there have been
extensive Mm changes in Vista, and !address wasn’t updated to
work with them). On WS03 and earlier (which is what the OP seems
to be using) it should still work, even with the latest debugger.

If you need to look at 32-bit system VA usage on Vista and later
you can try !vm 21 and db nt!MiSystemVaType (each byte in this
array represents a PDE’s worth of kernel VA space). Possible VA
types (session space, pool, etc) are represented by the
nt!_MI_SYSTEM_VA_TYPE enum.

–
This posting is provided “AS IS” with no warranties, and confers no
rights.

5

We run under Xp Sp2 :slight_smile: but good to know for our obsolescence study .

Thanks
Maxime