Brings back lfs3_btrv_t, but keeps some of the btree internal changes.
I think the biggest one is dropping the internal branch pointer, now
instead of internally pointing to the root rbyd, we just unconditionally
sync the rbyd state anytime the rbyd matches the root's weight. This is
necessary to avoid out-of-sync state when traversing bshrubs under
mutation.
Also after refactoring I think the current btree traversal logic is
easier to read.
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This is in preparation for removing the leaf cache, or at least making
it opt-in.
It adds a chunk of stack, but in theory we can reclaim this by allowing
leaf caches to be disabled:
code stack ctx
before: 37160 2352 688
after: 37088 (-0.2%) 2384 (+1.4%) 688 (+0.0%)
Christopher Haster
39a265ce90