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When pagefiles are opened?
OSR_Community_User
Member Posts: 110,217
in NTFSD
Hi All!
I have few questions about NT filesystems and page files:
1. When NT opens pagefiles?
2. How they are opened? Via IRP or FastIO? Are any special open flags present?
Do FS need initialize caching for pagefile?
Regards, Dennis
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I have few questions about NT filesystems and page files:
1. When NT opens pagefiles?
2. How they are opened? Via IRP or FastIO? Are any special open flags present?
Do FS need initialize caching for pagefile?
Regards, Dennis
__________________________________________________
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Talk to your friends online with Yahoo! Messenger.
http://im.yahoo.com
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Comments
Surely no. They are used for paging IO only - and all paging IO must bypass
the cache.
Max
NTSYSAPI
NTSTATUS
NTAPI
NtCreatePagingFile (
IN PUNICODE_STRING PageFileName,
IN PLARGE_INTEGER InitialSize,
IN PLARGE_INTEGER MaximumSize,
IN ULONG Reserved
);
This routine is usually called by SMSS.EXE after it performs
some critical operations (autochecks, file renames etc.).
There is a key in registry \Registry\Machine\System\CurrentControlSetControl\Session Manager\Memory management containing value
PagingFiles of type REG_MULTI_SZ. This one contains list of:
- file name (eg.
- initial size (eg. 43 [MB])
- maximum size (eg. 65 [MB]) (optional).
Routine NtCreatePagingFile calls IoCreateFile with Options
IO_OPEN_PAGING_FILE. This is present in create irp stack
location as SL_OPEN_PAGING_FILE.
FS should in this moment read all allocation for this file
to the resident memory and both the FCB and CCB should
also be allocated from non-paged pool. This is because when
processing the I/O to the paging file you have to translate file
run into disk runs and call the disk driver - ie. no cache is
maintained - and at this time also no page faults can occur.
Paul
> -----P?vodn? zpr?va-----
> Od: Dennis [SMTP:[email protected]]
> Odesl?no: 13. kv?tna 2000 1:39
> Komu: File Systems Developers
> P?edm?t: [ntfsd] When pagefiles are opened?
>
> Hi All!
>
> I have few questions about NT filesystems and page files:
> 1. When NT opens pagefiles?
> 2. How they are opened? Via IRP or FastIO? Are any special open flags
> present?
> Do FS need initialize caching for pagefile?
>
> Regards, Dennis
>
>
>
> __________________________________________________
>
> Do You Yahoo!?
>
> Talk to your friends online with Yahoo! Messenger.
>
> http://im.yahoo.com
>
>
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