chentianya/levelx
1
0
Fork 0
mirror of https://github.com/eclipse-threadx/levelx.git synced 2026-09-14 20:48:51 +08:00
Code Issues Packages Projects Releases Wiki Activity

Added opt-in lazy sector release to reduce O(N²) deletion (issue #70) (#71)

Browse Source 
WARNING: This feature is brand new and has not been tested beyond the
existing regression suite.  It should be thoroughly tested — including
stress, power-loss, and wear-levelling scenarios — before being used in
any production system.

When LX_NAND_FLASH_ENABLE_LAZY_SECTOR_RELEASE is defined and free blocks
exceed LX_NAND_FLASH_SECTOR_RELEASE_LAZY_THRESHOLD (default 10), releasing
a sector from a full block defers the copy+erase.  A tombstone page is
written to a freshly-allocated block; the old full block is flagged
COMPACTION_PENDING in its block status and recorded in a new per-LG
compaction table.  Compaction (merge + erase) is triggered lazily:

  * sector_write: before writing to a full block with a pending source
  * block_data_move: intercepts wear-levelling moves for pending LGs
  * defragment: iterates all pending LGs (now actually implemented)
  * block_allocate: emergency compaction when the free list is empty

Reads transparently fall back to the compaction-pending block when the
primary block does not contain the requested sector.

Crash recovery is handled in open_extended:
  - Phase 1: detects COMPACTION_PENDING blocks and either clears the flag
    (crash before mapping update — abort) or rebuilds compaction_table
    (crash after mapping update — resume deferred compaction).
  - Phase 2: erases orphaned ALLOCATED blocks not present in any mapping.

Without the flag, all paths remain unchanged and defragment returns
LX_NOT_SUPPORTED as before.

Fixes: https://github.com/eclipse-threadx/levelx/issues/70

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
This commit is contained in:
Frédéric Desbiens
2026-06-02 11:25:12 -04:00
committed by GitHub
co-authored by Copilot
parent a46b74fb8a
commit bfb39676df
11 changed files with 990 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files
common/src/lx_nand_flash_block_allocate.c
+38
View File
@@ -9,6 +9,7 @@
* SPDX-License-Identifier: MIT
**************************************************************************/
// Some portions generated by Copilot (Sonnet 4.6).
/**************************************************************************/
/**************************************************************************/
@@ -75,6 +76,43 @@ UINT _lx_nand_flash_block_allocate(LX_NAND_FLASH* nand_flash, ULONG* block)
if (nand_flash -> lx_nand_flash_free_block_list_tail == 0)
{
#ifdef LX_NAND_FLASH_ENABLE_LAZY_SECTOR_RELEASE
{
ULONG lg;
UINT compact_status;
/* Emergency compaction: find any pending compaction and execute it to
reclaim the old full block. */
for (lg = 0; lg < nand_flash -> lx_nand_flash_total_blocks; lg++)
{
if (nand_flash -> lx_nand_flash_block_compaction_table[lg] != (USHORT)LX_NAND_BLOCK_UNMAPPED)
{
compact_status = _lx_nand_flash_logical_group_compact(nand_flash, lg);
if (compact_status == LX_SUCCESS)
{
/* Retry the allocation after compaction freed a block. */
if (nand_flash -> lx_nand_flash_free_block_list_tail > 0)
{
nand_flash -> lx_nand_flash_free_block_list_tail--;
*block = nand_flash -> lx_nand_flash_block_list[nand_flash -> lx_nand_flash_free_block_list_tail];
return(LX_SUCCESS);
}
}
/* Attempt only one compaction per allocate call. */
break;
}
}
}
#endif /* LX_NAND_FLASH_ENABLE_LAZY_SECTOR_RELEASE */
/* Empty list, return error. */
return(LX_NO_BLOCKS);
}