In message <[EMAIL PROTECTED]>, Ville-Pertti Keinonen writes:
>Replying to myself...
>> Looking at the code, it would seem that the number of directories is
>> what's causing problems (one is created for each link).  The directory
>> vnodes can't be thrown out because a name cache entry exists in each
>> one.  All of the name cache entries point to the same vnode, which
>> can't be thrown out because it is open.
>My initial guess wasn't correct (I mis-read the program due to the
>lack of indentation) - huge amounts of memory actually are consumed by
>name cache entries, not just vnodes...
>Balancing the sizes of multiple caches can get quite interesting.

I have been mulling over this issue for some time.  My current thinking
is that pending some more well thought out mechanism, the right thing
to do here is to detect the DOS and react to that, not to handicap
the caching in general.

The easiest way to detect this DOS is probably to keep track of the

        namecache entries
        live vnodes

ratio, and enforce an upper limit on it.

Poul-Henning Kamp             FreeBSD coreteam member
[EMAIL PROTECTED]               "Real hackers run -current on their laptop."
FreeBSD -- It will take a long time before progress goes too far!

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