[PATCH bpf-next v3 0/1] docs/bpf: Add description of register liveness tracking algorithm

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An overview of the register tracking liveness algorithm.
Previous versions posted here: [1], [2].
- Changes from RFC to v1 (suggested by Andrii Nakryiko):
  - wording corrected to use term "stack slot" instead of "stack spill";
  - parentage chain diagram updated to show nil links for frame #1;
  - added example for non-BPF_DW writes behavior;
  - explanation in "Read marks propagation for cache hits" is reworked.
- Changes from v1 to v2:
  - lot's of grammatical / wording fixes as suggested by David Vernet;
  - "Register parentage chains" section is fixed to reflect what
    happens to r1-r5 when function call is processed (as suggested by David and Alexei);
  - Example in "Liveness marks tracking" section updated to explain
    why partial writes should not lead to REG_LIVE_WRITTEN marks
    (suggested by David);
  - "Read marks propagation for cache hits" section updates:
    - Explanation updated to hint why read marks should be propagated
      before jumping to example (suggested by David);
    - Removed box around B/D in the diagram updated (suggested by Alexei).

[1] https://lore.kernel.org/bpf/20230124220343.2942203-1-eddyz87@xxxxxxxxx/
[2] https://lore.kernel.org/bpf/20230130182400.630997-1-eddyz87@xxxxxxxxx/

Eduard Zingerman (1):
  docs/bpf: Add description of register liveness tracking algorithm

 Documentation/bpf/verifier.rst | 280 +++++++++++++++++++++++++++++++++
 1 file changed, 280 insertions(+)

-- 
2.39.0




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