virtual memory file size change

NTFSD
1

I am tracking down a reported problem (on W2k) that my driver stops when
“Windows reported it needed a bigger virtual memory file”. The driver
filters all drives, including the system volume.

I have never seen this message myself, so I have never tested whether I may
have a problem there. My two questions are:

  1. What Win32 actions can I take (in a test program) to make this state
    occur and so exercise my driver?
  2. What (in general) happens to FSDs and filters when this message appears?

Thanks

Brian

2

Run with a low size pagefile, low physicall memory, then allocate hughe
chunks of virtual memory. Sooner or later youll run into this.

For point 2 , it would be helpfull to know what your filter driver does.
During this message appears, the system pagefile size is extended, and its
in memory representations tweaked acordingly. During this process, some
virtual memory allocation requests may be denied,
best to my knowledge.

----- Original Message -----
From: “Brian Collins”
Newsgroups: ntfsd
To: “File Systems Developers”
Sent: Monday, August 26, 2002 10:30 AM
Subject: [ntfsd] virtual memory file size change

> I am tracking down a reported problem (on W2k) that my driver stops when
> “Windows reported it needed a bigger virtual memory file”. The driver
> filters all drives, including the system volume.
>
> I have never seen this message myself, so I have never tested whether I
may
> have a problem there. My two questions are:
> 1) What Win32 actions can I take (in a test program) to make this state
> occur and so exercise my driver?
> 2) What (in general) happens to FSDs and filters when this message
appears?
>
> Thanks
>
> Brian
>
>
>
> —
> You are currently subscribed to ntfsd as: xxxxx@rdsor.ro
> To unsubscribe send a blank email to %%email.unsub%%
>

3

Thanks for the pointers for testing.

AFAIK the driver should be a simple pass-thru other than for CREATEs
identified as being for the driver’s files, and for actions on file objects
opened by such creates. So I would not expect pagefile operations to affect
it. It does have some volume tracking to support removable media, so I had
been wondering about transient dismounts and re-mounts.

Anyway, I shall investigate and discover for myself what occurs.

Brian

“Dan Partelly” wrote in message news:xxxxx@ntfsd…
>
> Run with a low size pagefile, low physicall memory, then allocate hughe
> chunks of virtual memory. Sooner or later youll run into this.
>
> For point 2 , it would be helpfull to know what your filter driver does.
> During this message appears, the system pagefile size is extended, and its
> in memory representations tweaked acordingly. During this process, some
> virtual memory allocation requests may be denied,
> best to my knowledge.
>
>
>
> ----- Original Message -----
> From: “Brian Collins”
> Newsgroups: ntfsd
> To: “File Systems Developers”
> Sent: Monday, August 26, 2002 10:30 AM
> Subject: [ntfsd] virtual memory file size change
>
>
> > I am tracking down a reported problem (on W2k) that my driver stops when
> > “Windows reported it needed a bigger virtual memory file”. The driver
> > filters all drives, including the system volume.
> >
> > I have never seen this message myself, so I have never tested whether I
> may
> > have a problem there. My two questions are:
> > 1) What Win32 actions can I take (in a test program) to make this state
> > occur and so exercise my driver?
> > 2) What (in general) happens to FSDs and filters when this message
> appears?
> >
> > Thanks
> >
> > Brian
> >
> >
> >
> > —
> > You are currently subscribed to ntfsd as: xxxxx@rdsor.ro
> > To unsubscribe send a blank email to %%email.unsub%%
> >
>
>
>
>

4

It turned out not to be a driver problem. Some Win32 library code (Apache)
could not cope with the allocation failures that Dan mentions.

“Brian Collins” wrote in message
news:xxxxx@ntfsd…
>
> Thanks for the pointers for testing.
>
> AFAIK the driver should be a simple pass-thru other than for CREATEs
> identified as being for the driver’s files, and for actions on file
objects
> opened by such creates. So I would not expect pagefile operations to
affect
> it. It does have some volume tracking to support removable media, so I had
> been wondering about transient dismounts and re-mounts.
>
> Anyway, I shall investigate and discover for myself what occurs.
>
> Brian
>
> “Dan Partelly” wrote in message
news:xxxxx@ntfsd…
> >
> > Run with a low size pagefile, low physicall memory, then allocate hughe
> > chunks of virtual memory. Sooner or later youll run into this.
> >
> > For point 2 , it would be helpfull to know what your filter driver does.
> > During this message appears, the system pagefile size is extended, and
its
> > in memory representations tweaked acordingly. During this process, some
> > virtual memory allocation requests may be denied,
> > best to my knowledge.
> >
> >
> >
> > ----- Original Message -----
> > From: “Brian Collins”
> > Newsgroups: ntfsd
> > To: “File Systems Developers”
> > Sent: Monday, August 26, 2002 10:30 AM
> > Subject: [ntfsd] virtual memory file size change
> >
> >
> > > I am tracking down a reported problem (on W2k) that my driver stops
when
> > > “Windows reported it needed a bigger virtual memory file”. The driver
> > > filters all drives, including the system volume.
> > >
> > > I have never seen this message myself, so I have never tested whether
I
> > may
> > > have a problem there. My two questions are:
> > > 1) What Win32 actions can I take (in a test program) to make this
state
> > > occur and so exercise my driver?
> > > 2) What (in general) happens to FSDs and filters when this message
> > appears?
> > >
> > > Thanks
> > >
> > > Brian
> > >
> > >
> > >
> > > —
> > > You are currently subscribed to ntfsd as: xxxxx@rdsor.ro
> > > To unsubscribe send a blank email to %%email.unsub%%
> > >
> >
> >
> >
> >
>
>
>
>