Merge branch 'kk/commit-graph-topo-levels-fix' into next

The 'topo_levels' slab was propagated only to the topmost layer of a split commit-graph chain, causing incremental writes to recompute topological levels for commits in base layers. This has been corrected. * kk/commit-graph-topo-levels-fix: commit-graph: propagate topo_levels slab to all chain layers commit-graph: add trace2 instrumentation for generation DFS