Re: [Lse-tech] Re: [RFC] dcache scalability patch (2.4.17)

[Paul Menage <pmenage@ensim.com>]

>
>
>On Sat, 13 Jul 2002, Paul Menage wrote:
>
>> - accessing foo/../bar, won't mark foo as referenced, even though it
>> might be being referenced frequently. Probably not a common case for foo
>> to be accessed exclusively in this way, but it could be fixed by marking
>> a dentry referenced when following ".."
>
>It certainly will.  Look - until ->d_count hits zero referenced bit is
>not touched or looked at.  At all.
>
>Look at the code.  There is _no_ aging for dentries with positive ->d_count.
>They start aging only when after they enter unused_list...
>

Yes, but with the fastwalk lookup, accessing foo/../bar won't do a
dget() for foo (assuming it was cached), and hence will never do a
dput() on it either. So if the only references to foo are as foo/../bar
then its d_count will stay zero and it will never be marked referenced.
(Or am I missing something?)

Paul