The one-entry cache lived inside schfs_file_read, so stat() never touched
it -- which is why `ls` barely moved. Moved into schfs_inode_get, where
every caller benefits, and widened to sixteen entries.
`ls` is the shape that matters: it stats every name in a directory, so a
single entry never hits and each file costs two descents, one to find the
name and one to read the inode. Sixteen keeps hitting through a directory
walk without a second reader evicting everything. Round-robin rather than
LRU: the pattern is a walk, not a working set, so the bookkeeping on every
hit would buy nothing.
Measured in the guest, TCG, against the original baseline:
ls /bin warm 0.70s -> 0.43s
ls /bin cold 2.80s -> 1.32s
read 834 KB 1.73s -> 0.35s
schfs-check passes including the round-trip; bootcheck 108 [ok].
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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