Re: non-paged memory inside a kernel driver

you will not get such a number. let's say 20 instance of such a driver was loaded and the number was 10%. then at least half of them would not be able to load. moreover, it depends on the state of system memory when you try to allocate memory, the virtual address space has to have a big enough gap (e.g. it is not fragmented) to fit your allocation.

what are you going to do with the memory once you have
allocated it?

d
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"krish" <pradeep_bisht@xxxxxxxxx> wrote in message news:551587ae-46e4-49bb-bb70-06900bca6125@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Hi Don, large is kind of relative term :-). Would you suggest any
number in terms of percentage of the available memory like 10%, 20%
etc which you think is safe enough? Or from your experience, what is
the largest amount that you have seen in a well performing kernel mode
driver? Thanks.

On Mar 31, 2:01 pm, "Don Burn" <b...@xxxxxxxxxxxxxxxxxxxx> wrote:
Pre-Vista it is 128MB, but even in Vista doing a large allocate is a really
bad idea, since then the rest of the system will be starved, and likely to
crash.

--
Don Burn (MVP, Windows DDK)
Windows 2k/XP/2k3 Filesystem and Driver Consulting
Website:http://www.windrvr.com
Blog:http://msmvps.com/blogs/WinDrvr
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"krish" <pradeep_bi...@xxxxxxxxx> wrote in message

news:a4bc5006-05a9-4340-8e3c-b7a2ca72cf76@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

> Hi, what is the maximum size of non-paged memory that I can allocate
> inside inside my kernel driver in XP and Vista? I took the diskperf
> from WDK, modified it and on Vista, 32-bit, 2GB RAM, I tried
> allocating 4/8/100/512 MB and I was able to do it successfully while
> allocating 1GB and above failed. Is there any hard restriction on the
> amount of non-paged memory I can allocate inside my driver?

> Thanks in anticipation.


.

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