locked == NonPaged ?

NTFSD
1

Thank you for the shared memory advices. It’s working now, but I want to
avoid that the system swaps out my shared memory
area. ZwCreateSection() and ZwMapViewOfSection() allocates NonPeged pool
which can be swapped, but if I call IoAllocateMdl() and
MmProbeAndLockPages() can I prevent my data being swapped ? Or what is
exactly the difference between locked and nonpaged memory ?

Thanks in advance.

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2

> which can be swapped, but if I call IoAllocateMdl() and

MmProbeAndLockPages() can I prevent my data being swapped ?

Yes, MmProbeAndLockPages prevents the data from being swapped.

Max

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3

Hi Illes,

  1. NonPaged pool cannot be “paged” or swapped out. (I guess that was a
    typo in your mail).

  2. The difference between locked pages and nonpaged memory is that
    nonpaged memory is a global non-pageable pool in the system address
    space, while pinning (or locking) pages disallows pageable memory from
    being paged (or swapped out) even during context switches.

  3. If those locked pages are in the user-mode context, the macro
    MmGetSystemAddressForMdlSafe, will allow you to access that memory from
    kernel mode in an arbitrary thread context.

I hope this makes things clearer.

Youssef

-----Original Message-----
From: Illes Attila [mailto:xxxxx@ktk.bme.hu]
Sent: Monday, July 23, 2001 1:18 AM
To: File Systems Developers
Subject: [ntfsd] locked == NonPaged ?

Thank you for the shared memory advices. It’s working now, but I want to

avoid that the system swaps out my shared memory

area. ZwCreateSection() and ZwMapViewOfSection() allocates NonPeged pool

which can be swapped, but if I call IoAllocateMdl() and

MmProbeAndLockPages() can I prevent my data being swapped ? Or what is

exactly the difference between locked and nonpaged memory ?

Thanks in advance.

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