Re: ENTRY_SPECIAL => content pinning?

Hi Joe

--- Joe Cooper <joe@swelltech.com> wrote:
> Hi Yee Man,
>
> I was looking at this myself. I think you've missed
> the store_swapout.c
> reference to ENTRY_SPECIAL...if you made this the
> entry type for pinned
> objects they would never get to disk.
>

You are right that these ENTRY_SPECIAL objects are not
SwapOutAble. I ran through gdb and see that MIME
images are loaded to the store_table in mimeInit with
ENTRY_SPECIAL. So do they always stay in memory and
never get swapped out?

> I think adding a new type "ENTRY_PINNED" that
> behaves sort of like
> ENTRY_SPECIAL, without the swapout limitation might
> be more intuitive
> and self-explanatory for folks reading the code.
>
> My thoughts have run to implementation details:
> Should pinning use ACLs
> or a pattern like 'refresh_pattern'?
>

Maybe refresh_pattern because I think people only want
to pin an object for a period of time instead of
forever. So something resembles an expiration
mechanism
should be appropriate.

Yee Man
  
> Yee Man Chan wrote:
> > Hi
> >
> > I read some posts in isp-caching and people are
> > talking about content pinning, ie store something
> in
> > cache and it will never be purged. I see that in
> our
> > removal policy modules, we ignore all
> ENTRY_SPECIAL
> > entries. Is it true that if we set the objects we
> want
> > to pin to ENTRY_SPECIAL, then we can achieve
> content
> > pinning?
> >
> > Thanks.
> > Yee Man
> >
> > __________________________________________________
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>
>
> --
> Joe Cooper <joe@swelltech.com>
> Web caching appliances and support.
> http://www.swelltech.com
>

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Received on Sat May 25 2002 - 15:29:07 MDT