progcache: trim allocations#10115
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riptl
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Jun 6, 2026
riptl
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- wksp: add trim method
- progcache: trim allocations
Allow shrinking existing wksp allocations
Trim program cache record allocation to save space when loading over-allocated program data accounts. In theory, we could just allocate less space in the first place, to avoid the need for trimming. This patch for simplicity, not touching existing code.
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Pull request overview
This PR introduces an in-place “trim” capability for workspace-backed allocations and uses it to reduce post-load memory usage in the program cache (where deployers often over-allocate program accounts).
Changes:
- Add
fd_wksp_trim()to shrink an existing wksp allocation and add wksp tests/fuzz-op coverage for trimming. - Add
fd_alloc_trim()to expose trimming for large (wksp-direct)fd_allocallocations, plus allocator tests. - Add
fd_progcache_rec_compact()and call it after program load to trim away unused tail space.
Reviewed changes
Copilot reviewed 9 out of 9 changed files in this pull request and generated 4 comments.
Show a summary per file
| File | Description |
|---|---|
| src/util/wksp/test_wksp_user.c | Adds explicit and randomized tests for fd_wksp_trim() |
| src/util/wksp/fd_wksp.h | Exposes new fd_wksp_trim() API |
| src/util/wksp/fd_wksp_user.c | Implements fd_wksp_trim() logic (split/merge free partitions, ASan poison) |
| src/util/alloc/test_alloc.c | Adds tests for fd_alloc_trim() behavior |
| src/util/alloc/fd_alloc.h | Exposes new fd_alloc_trim() API |
| src/util/alloc/fd_alloc.c | Implements fd_alloc_trim() for large allocations |
| src/flamenco/progcache/fd_progcache_user.c | Calls record compaction after successful load attempt |
| src/flamenco/progcache/fd_progcache_rec.h | Declares fd_progcache_rec_compact() and documents intent |
| src/flamenco/progcache/fd_progcache_rec.c | Implements fd_progcache_rec_compact() using trimming |
| up less space. Solana program deployers typically over-allocate the | ||
| program data account (by about 2x) to support future growth. During | ||
| ELF loading, the entire size of the program might be used for scratch | ||
| calculations (due to awful ELF relocation semenatics). But after |
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| int | ||
| fd_wksp_trim( fd_wksp_t * wksp, | ||
| ulong gaddr, | ||
| ulong sz ); |
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| int | ||
| fd_alloc_trim( fd_alloc_t * join, | ||
| void * laddr, | ||
| ulong sz ); |
riptl
commented
Jun 6, 2026
| #include "../vm/fd_vm.h" /* fd_vm_syscall_register_slot, fd_vm_validate */ | ||
| #include "../../util/alloc/fd_alloc.h" | ||
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| #include <stdatomic.h> |
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