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preerase: Inverted LFS3_PREERASE to be opt-in

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The original motivation for making LFS3_PREERASE opt-out, is that it
makes sense for LFS3_GBMAP to bring in all gbmap-related features
(PREERASE, BADBLOCKS (future)). However, after a bit of use, I think
this just complicates our ifdef logic too much.

So instead, LFS3_PREERASE is now opt-in, with the intention of making
all ifdefs relative only to the default build. I think this will make it
easier to reason about ifdefs, at least internally.

Eventually, I want to look into alternative default builds (LFS3_BIGGER,
LFS3_BIGGERR, ..., LFS3_BIGGEST), which would provide an alternative way
to enable all gbmap-related features. Though these builds have a
high-risk of bikeshedding (LFS3_GC?), so we'll see.

---

That being said, the main ergonomic improvement was probably adding
a #error, so we don't have to check ifdef GBMAP everywhere.

Maybe this should be extended to LFS3_RDONLY? Or maybe not, LFS3_RDONLY
is a bit of a special case.

No code changes:

                    code          stack          ctx
  before:          35144           2136          660
  after:           35144 (+0.0%)   2136 (+0.0%)  660 (+0.0%)

                    code          stack          ctx
  gbmap before:    38380           2144          776
  gbmap after:     38380 (+0.0%)   2144 (+0.0%)  776 (+0.0%)

                    code          stack          ctx
  preerase before: 38920           2168          796
  preerase after:  38920 (+0.0%)   2168 (+0.0%)  796 (+0.0%)
This commit is contained in:
Christopher Haster
2025-12-30 00:28:38 -06:00
parent 1d6fa2e5f1
commit ecd780a313
5 changed files with 74 additions and 112 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lfs3.h
+13 -25
View File
@@ -212,7 +212,7 @@ enum lfs3_type {
#define LFS3_F_LOOKAHEAD \
0x00000200 // Repopulate lookahead/gbmap
#endif
#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
#define LFS3_F_PREERASE 0x00000400 // Try to pre-erase free blocks
#endif
#ifndef LFS3_RDONLY
@@ -232,9 +232,7 @@ enum lfs3_type {
#define LFS3_F_GC ( \
LFS3_IFDEF_RDONLY(0, LFS3_F_MKCONSISTENT) \
| LFS3_IFDEF_RDONLY(0, LFS3_F_LOOKAHEAD) \
| LFS3_IFDEF_RDONLY(0, \
LFS3_IFDEF_GBMAP( \
LFS3_IFDEF_PREERASE(LFS3_F_PREERASE, 0), 0)) \
| LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_PREERASE(LFS3_F_PREERASE, 0)) \
| LFS3_IFDEF_RDONLY(0, LFS3_F_COMPACT) \
| LFS3_F_CKMETA \
| LFS3_F_CKDATA)
@@ -277,7 +275,7 @@ enum lfs3_type {
#define LFS3_M_LOOKAHEAD \
0x00000200 // Repopulate lookahead/gbmap
#endif
#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
#define LFS3_M_PREERASE 0x00000400 // Try to pre-erase free blocks
#endif
#ifndef LFS3_RDONLY
@@ -293,9 +291,7 @@ enum lfs3_type {
#define LFS3_M_GC ( \
LFS3_IFDEF_RDONLY(0, LFS3_M_MKCONSISTENT) \
| LFS3_IFDEF_RDONLY(0, LFS3_M_LOOKAHEAD) \
| LFS3_IFDEF_RDONLY(0, \
LFS3_IFDEF_GBMAP( \
LFS3_IFDEF_PREERASE(LFS3_M_PREERASE, 0), 0)) \
| LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_PREERASE(LFS3_M_PREERASE, 0)) \
| LFS3_IFDEF_RDONLY(0, LFS3_M_COMPACT) \
| LFS3_M_CKMETA \
| LFS3_M_CKDATA)
@@ -337,7 +333,7 @@ enum lfs3_type {
#define LFS3_I_LOOKAHEAD \
0x00000200 // Lookahead/gbmap is not full
#endif
#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
#define LFS3_I_PREERASE 0x00000400 // Blocks can be pre-erased
#endif
#ifndef LFS3_RDONLY
@@ -370,7 +366,7 @@ enum lfs3_btype {
#define LFS3_T_LOOKAHEAD \
0x00000200 // Repopulate lookahead/gbmap
#endif
#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
#define LFS3_T_PREERASE 0x00000400 // Try to pre-erase free blocks
#endif
#ifndef LFS3_RDONLY
@@ -395,9 +391,7 @@ enum lfs3_btype {
#define LFS3_T_GC ( \
LFS3_IFDEF_RDONLY(0, LFS3_T_MKCONSISTENT) \
| LFS3_IFDEF_RDONLY(0, LFS3_T_LOOKAHEAD) \
| LFS3_IFDEF_RDONLY(0, \
LFS3_IFDEF_GBMAP( \
LFS3_IFDEF_PREERASE(LFS3_T_PREERASE, 0), 0)) \
| LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_PREERASE(LFS3_T_PREERASE, 0)) \
| LFS3_IFDEF_RDONLY(0, LFS3_T_COMPACT) \
| LFS3_T_CKMETA \
| LFS3_T_CKDATA)
@@ -411,7 +405,7 @@ enum lfs3_btype {
#define LFS3_CK_LOOKAHEAD \
0x00000200 // Repopulate lookahead/gbmap
#endif
#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
#define LFS3_CK_PREERASE \
0x00000400 // Try to pre-erase free blocks
#endif
@@ -428,9 +422,7 @@ enum lfs3_btype {
#define LFS3_CK_GC ( \
LFS3_IFDEF_RDONLY(0, LFS3_CK_MKCONSISTENT) \
| LFS3_IFDEF_RDONLY(0, LFS3_CK_LOOKAHEAD) \
| LFS3_IFDEF_RDONLY(0, \
LFS3_IFDEF_GBMAP( \
LFS3_IFDEF_PREERASE(LFS3_CK_PREERASE, 0), 0)) \
| LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_PREERASE(LFS3_CK_PREERASE, 0)) \
| LFS3_IFDEF_RDONLY(0, LFS3_CK_COMPACT) \
| LFS3_CK_CKMETA \
| LFS3_CK_CKDATA)
@@ -444,7 +436,7 @@ enum lfs3_btype {
#define LFS3_GC_LOOKAHEAD \
0x00000200 // Repopulate lookahead/gbmap
#endif
#if !defined(LFS3_RDONLY) && defined(LFS3_GBMAP) && !defined(LFS3_NO_PREERASE)
#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
#define LFS3_GC_PREERASE \
0x00000400 // Try to pre-erase free blocks
#endif
@@ -461,9 +453,7 @@ enum lfs3_btype {
#define LFS3_GC_GC ( \
LFS3_IFDEF_RDONLY(0, LFS3_GC_MKCONSISTENT) \
| LFS3_IFDEF_RDONLY(0, LFS3_GC_LOOKAHEAD) \
| LFS3_IFDEF_RDONLY(0, \
LFS3_IFDEF_GBMAP( \
LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0), 0)) \
| LFS3_IFDEF_RDONLY(0, LFS3_IFDEF_PREERASE(LFS3_GC_PREERASE, 0)) \
| LFS3_IFDEF_RDONLY(0, LFS3_GC_COMPACT) \
| LFS3_GC_CKMETA \
| LFS3_GC_CKDATA)
@@ -625,9 +615,7 @@ struct lfs3_cfg {
// value >= block_count attempts to pre-erase all known free blocks
// during gc.
//
#if !defined(LFS3_RDONLY) \
&& defined(LFS3_GBMAP) \
&& !defined(LFS3_NO_PREERASE)
#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
lfs3_block_t gc_preerase_count;
#endif
@@ -1383,7 +1371,7 @@ typedef struct lfs3 {
#if !defined(LFS3_RDONLY)
lfs3_sblock_t next;
#endif
#if !defined(LFS3_RDONLY) && !defined(LFS3_NO_PREERASE)
#if !defined(LFS3_RDONLY) && defined(LFS3_PREERASE)
lfs3_ecksum_t ecksum;
struct lfs3_preeraser {
lfs3_block_t known;