feat: add sector-aligned mmap flush#3
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jgwesterlund wants to merge 1 commit intofeat/write-coalescingfrom
Open
feat: add sector-aligned mmap flush#3jgwesterlund wants to merge 1 commit intofeat/write-coalescingfrom
jgwesterlund wants to merge 1 commit intofeat/write-coalescingfrom
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Add sector_size parameter to flush only aligned mmap regions covering written data instead of the entire mapping. Integrates with both direct writes and wrap marker writes. Falls back to full flush when sector_size=0. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Pull Request
What does this change do?
Adds a
sector_sizeparameter to flush only the sector-aligned mmap regions covering written data, instead of flushing the entire mapping. Integrates with both direct writes and wrap marker writes.Why is this needed?
On block devices with specific sector sizes (e.g., SD cards with 512 or 4096-byte sectors), full-mapping flushes are expensive. Sector-aligned flushing targets only the modified sectors, improving write performance on constrained devices.
Type of change
How was this tested?
4 new tests in
tests/test_extended.py:sector_size=0falls back to normal flushAll 47 tests pass, 98% coverage, ruff clean, mypy clean.
Checklist
Notes for reviewers
This PR is based on
feat/write-coalescing(PR #2) since sector-aligned flush integrates with the coalesced flush path.The flush alignment uses
max(sector_size, mmap.PAGESIZE)to satisfy macOS page-alignment requirements for msync.Docs updated:
usage.md,api.md.