!memusage bad memory

NTDEV
1

Hi,

? The output of !memusage shows KB marked as bad. Does this mean that the RAM is corrupted? The startup memory test did not detect errors.

? Any insight is helpful. Thanks,
? ? Calin

lkd> !memusage 8
?loading PFN database
loading (100% complete)
Compiling memory usage data (99% Complete).
? ? ? ? ? ? ?Zeroed: 545998 (2183992 kb)
? ? ? ? ? ? ? ?Free: ? ? ?8 ( ? ?32 kb)
? ? ? ? ? ? Standby: 116439 (465756 kb)
? ? ? ? ? ?Modified: ?18989 ( 75956 kb)
? ? ModifiedNoWrite: ? ? ?0 ( ? ? 0 kb)
? ? ? ?Active/Valid: 146843 (587372 kb)
? ? ? ? ?Transition: ? ? ?2 ( ? ? 8 kb)
? ? ? ? ? ? ? ? Bad: ? 1400 ( ?5600 kb)
? ? ? ? ? ? Unknown: ? ? ?0 ( ? ? 0 kb)
? ? ? ? ? ? ? TOTAL: 828279 (3313116 kb)

2

No, it doesn’t necessarily mean that the memory is actually bad. There’s an
Mm API that can be called to put pages in this state and it’s a state used
internally in the Mm for various reasons.

-scott
OSR

“Calin Iaru” wrote in message news:xxxxx@ntdev…
Hi,

The output of !memusage shows KB marked as bad. Does this mean that the
RAM is corrupted? The startup memory test did not detect errors.

Any insight is helpful. Thanks,
Calin

lkd> !memusage 8
loading PFN database
loading (100% complete)
Compiling memory usage data (99% Complete).
Zeroed: 545998 (2183992 kb)
Free: 8 ( 32 kb)
Standby: 116439 (465756 kb)
Modified: 18989 ( 75956 kb)
ModifiedNoWrite: 0 ( 0 kb)
Active/Valid: 146843 (587372 kb)
Transition: 2 ( 8 kb)
Bad: 1400 ( 5600 kb)
Unknown: 0 ( 0 kb)
TOTAL: 828279 (3313116 kb)

3

You can also check how many pages were actually inserted into the bad page
list, see comments here: http://analyze-v.com/?p=558 from Pavel Lebedinsky.
Some drivers can mark memory pages as bad (e.g. by calling
MmMarkPhysicalMemoryAsBad).

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Scott Noone
Sent: Friday, April 19, 2013 4:47 PM
To: Windows System Software Devs Interest List
Subject: Re:[ntdev] !memusage bad memory

No, it doesn’t necessarily mean that the memory is actually bad. There’s an
Mm API that can be called to put pages in this state and it’s a state used
internally in the Mm for various reasons.

-scott
OSR