Hi All,
what will be the maximum Nonpaged pool memory that can be allocated in the kernel mode WDM driver. I am dumping the data into file using the Zw calls from my driver, I need to dump the data having the size of more than 25 MB. Now I am able to dump upto 10 MB.
Please send your valuable suggestions which will be more helpful.
Thanks & Regards,
Cyril
Formula 1 fan? This is for you! Best pics of the year.
25MB off of non-paged pool? That’s quite a lot. Do you really need to use
non-paged pool? Can you break this buffer into smaller chunks? If you tell
us more about what you want to do, we can help you better.
Mat
-----Original Message-----
From: sagaya cyril [mailto:xxxxx@hotmail.com]
Sent: Thursday, July 17, 2003 12:44 AM
To: Windows System Software Developers Interest List
Subject: [ntdev] Non paged pool Memory size
Hi All,
?what will be the maximum Nonpaged pool memory that can be allocated in the
kernel mode WDM driver.?I am dumping the data into file using the Zw calls
from my driver,?I need to dump the data having the size of more than 25 MB.
Now I am able to dump upto 10 MB.
Please send your valuable suggestions which will be more helpful.
?
Thanks & Regards,
Cyril
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it’s going to depend on a huge number of factors - from things like the
memory in the machine and the SKU installed which affect the base pool
sizes, to whether the customer has /3GB turned on (which really shrinks
the kernel VA space) to how fragmented the pool is, etc…
you’ve not provided a lot of information about what you’re trying to do,
so it’s hard to provide any better data about what the limits are or how
you might avoid hitting them.
Are you trying to allocate one single contiguous block? Or smaller
chunks? (the latter would be better)
Are you buffering data from user-mode? Or data from a device?
Do you really need to have all 25MB in memory at once? Are you writing
it out to disk gradually and still need to hit 25MB? That’s a pretty
high datarate.
Do you really need the memory to be non-paged pool? Or could you use
locked paged pool buffers (through MmProbeAndLockPages) and then unlock
them once you’ve put data into them?
You can call ZwAllocateVirtualMemory to allocate paged memory in the
user-mode address space of the system process (just like VirtualAlloc in
user-mode) which you can then access from a system thread. Locking this
memory down is tricky, but can be done.
all sorts of options
-p
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of sagaya cyril
Sent: Wednesday, July 16, 2003 9:44 PM
To: Windows System Software Developers Interest List
Subject: [ntdev] Non paged pool Memory size
Hi All,
what will be the maximum Nonpaged pool memory that can be
allocated in the kernel mode WDM driver. I am dumping the data into file
using the Zw calls from my driver, I need to dump the data having the
size of more than 25 MB. Now I am able to dump upto 10 MB.
Please send your valuable suggestions which will be more
helpful.
Thanks & Regards,
Cyril
Formula 1 fan? This is for you! Best pics of the year.
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Try paged pool.
----- Original Message -----
From: sagaya cyril
To: Windows System Software Developers Interest List
Sent: Thursday, July 17, 2003 8:44 AM
Subject: [ntdev] Non paged pool Memory size
Hi All,
what will be the maximum Nonpaged pool memory that can be allocated in the kernel mode WDM driver. I am dumping the data into file using the Zw calls from my driver, I need to dump the data having the size of more than 25 MB. Now I am able to dump upto 10 MB.
Please send your valuable suggestions which will be more helpful.
Thanks & Regards,
Cyril
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Is ZwAllocateVirtualMemory() an IFS API? Is it suitable for general use?
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James Antognini
Windows DDK MVP
It is documented in the IFS kit, there is no restriction on it that say it
must be a filesystem. Of couse if you are going for WHQL that is a
different story.
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
“James Antognini” wrote in message
news:LYRIS-796-120268-2003.07.17-14.38.49–burn#xxxxx@lists.osr.com…
> Is ZwAllocateVirtualMemory() an IFS API? Is it suitable for general use?
>
> –
> If replying by e-mail, please remove “nospam.” from the address.
>
> James Antognini
> Windows DDK MVP
>
>
>
> —
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You can create a section with NULL file handle and map it to user space, being
in the System process context. This gives you the nearly unlimited “paged
pool”.
Max
----- Original Message -----
From: “James Antognini”
Newsgroups: ntdev
To: “Windows System Software Developers Interest List”
Sent: Thursday, July 17, 2003 10:38 PM
Subject: [ntdev] Re: Non paged pool Memory size
> Is ZwAllocateVirtualMemory() an IFS API? Is it suitable for general use?
>
> –
> If replying by e-mail, please remove “nospam.” from the address.
>
> James Antognini
> Windows DDK MVP
>
>
>
> —
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Hi Mat,
I am capturing the real time data and storing it into the buffer continuously.
The idea is while disabling the driver,that data will be dumped into a file.
I am trying to capture the data as much as possible, that is why i need that much memory.
Thanks & Regards,
Cyril
----- Original Message -----
From: “Mathieu Routhier” <xxxxx@guillemot.com>
To: “Windows System Software Developers Interest List” <xxxxx@lists.osr.com>
Sent: Thursday, July 17, 2003 7:09 PM
Subject: [ntdev] RE: Non paged pool Memory size
25MB off of non-paged pool? That’s quite a lot. Do you really need to use
non-paged pool? Can you break this buffer into smaller chunks? If you tell
us more about what you want to do, we can help you better.
Mat
-----Original Message-----
From: sagaya cyril [mailto:xxxxx@hotmail.com]
Sent: Thursday, July 17, 2003 12:44 AM
To: Windows System Software Developers Interest List
Subject: [ntdev] Non paged pool Memory size
Hi All,
what will be the maximum Nonpaged pool memory that can be allocated in the
kernel mode WDM driver. I am dumping the data into file using the Zw calls
from my driver, I need to dump the data having the size of more than 25 MB.
Now I am able to dump upto 10 MB.
Please send your valuable suggestions which will be more helpful.
Thanks & Regards,
Cyril
It’s new, it’ here! It’s full of fun! MSN Messenger V6.0
----- Original Message -----
From: sagaya cyril
To: Windows System Software Developers Interest List
Sent: Thursday, July 17, 2003 12:44 AM
Subject: [ntdev] Non paged pool Memory size
Hi All,
what will be the maximum Nonpaged pool memory that can be allocated in the
kernel mode WDM driver. I am dumping the data into file using the Zw calls
from my driver, I need to dump the data having the size of more than 25 MB.
Now I am able to dump upto 10 MB.
Please send your valuable suggestions which will be more helpful.
Thanks & Regards,
Cyril
[snip]
Ok, while I have never used this routine, you may want to try
MmAllocatePagesForMdl. This does not tap nonpaged pool, but non paged
memory, so you may be in luck. Here is an osr article on how to use this
routine:
http://www.osronline.com/article.cfm?id=101
This routine is also mentioned in The NT Insider “Letters” section in
Volume 9, issue 4 (July-August 2002). In particular, the text mentions that
this routine can be used in WinXP and is suitable for large allocation
requests. I’m not sure about this routine’s availability on Win2k though.
OTOH, I’m still not sure on why you cannot break up this allocation into
smaller chunks, and write each chunk to disk at a convenient time.
Philip Lukidis
Yes, I knew it’s in the IFS. I was asking whether one can use it without
having the IFS. That is, is such use legitimate, in regard to WHQL or
anything else?
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James Antognini
Windows DDK MVP