Jeff Layton <jlay...@kernel.org> wrote:
> Since most cookies are fairly small, is there any real benefit to
> optimizing for length here? How much inflation are we talking about?
Taking AFS as an example, a vnode is represented at the file level by two
numbers: a 32-bit or 96-bit file ID and a 32-bit uniquifier. If it's a 96-bit
file ID, a lot of the time, the upper 64-bits will be zero, so we're talking
something like:
S421d4,1f07f34,,
instead of:
S000421d401f07f340000000000000000
or:
E0AAQh1AHwfzQAAAAAAAAAAA==
The first makes for a more readable name in the cache. The real fun is with
NFS, where the name can be very long. For one that's just 5 words in length:
T81010001,1,20153e2,,a906194b
instead of:
T8101000100000001020153e200000000a906194b
or:
E0gQEAAQAAAAECAVPiAAAAAKkGGUs=
(The letter on the front represents the encoding scheme; in the base64 encoding
the second digit indicates the amount of padding).
I don't know how much difference it makes to the backing filesystem's
directory packing - and it may depend on the particular filesystem.
David
--
Linux-cachefs mailing list
Linux-cachefs@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-cachefs
