SUMMARY: kernel tuning and mmap

From: Bryan Rank <bryan_at_compgen.com>
Date: Thu, 02 Sep 1999 15:03:29 -0400 (EDT)

Thanks to...

Alan
Serguei Patchkovsk
Keith Piepho



Serguei's reply seems to sum it up.
> I am doing some development which will require mmap'ping a 1.8 gig
> file into memory. I have two questions which don't seem to be covered in
> the man page or the system administrators guide.
>
> 1. Do I need to tune the kernel to allow that big of a file to be
> mmap'ed?

You might have. Make sure that 'sysconfig -q vm vm-maxvas' is large
enough to fit both the mmap'ed file and the process doing the mmap'ing.
Same for 'sysconfig -q proc max-per-proc-address-space'

> 2. Is there a way for me to ensure that the table (file) doesn't get
> swapped out? The machine will have 6 gig of RAM.

If you are absolutely sure this is what you want, mlock(3) will take
care of it. You may have to increase 'sysconfig -q vm vm-maxwire' to
do this.
~



On Thu, 2 Sep 1999, Bryan Rank wrote:

> Hello,
>
> I am doing some development which will require mmap'ping a 1.8 gig
> file into memory. I have two questions which don't seem to be covered in
> the man page or the system administrators guide.
>
> 1. Do I need to tune the kernel to allow that big of a file to be
> mmap'ed?
>
> 2. Is there a way for me to ensure that the table (file) doesn't get
> swapped out? The machine will have 6 gig of RAM.
>
>
>
> Thanks very much,
> will summarize,
>
>
> Bryan
>
>
Received on Thu Sep 02 1999 - 19:05:54 NZST

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