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Reduced the scope of LFS3_REVDBG/REVNOISE

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LFS3_REVDBG introduced a lot of overhead for something I'm not sure
anyone will actually use (I have enough tooling that the state of an
rbyd is rarely a mystery, see dbgbmap.py). That, and we're running out
of flags!

So this reduces LFS3_REVDBG to just store one of "himb" in the first
(lowest) byte of the revision count; information that is easily
available:

  vvvv---- -------- -------- --------
  vvvvrrrr rrrrrr-- -------- --------
  vvvvrrrr rrrrrrnn nnnnnnnn nnnnnnnn
  vvvvrrrr rrrrrrnn nnnnnnnn dddddddd
  '-.''----.----''----.- - - '---.--'
    '------|----------|----------|---- 4-bit relocation revision
           '----------|----------|---- recycle-bits recycle counter
                      '----------|---- pseudorandom noise (if revnoise)
                                 '---- h, i, m, or b (if revdbg)
                             -11-1---  - h = mroot anchor
                             -11-1--1  - i = mroot
                             -11-11-1  - m = mdir
                             -11---1-  - b = btree node

Some other notes:

- Enabled LFS3_REVDBG and LFS3_REVNOISE to work together, now that
  LFS3_REVDBG doesn't consume all unused rev bits.

  Note that LFS3_REVDBG has priority over LFS3_REVNOISE, but _not_
  recycle-bits, etc. Otherwise problems would happen for recycle-bits
  >2^20 (though do we care?).

- Fixed an issue where using the gcksum as a noise source results in
  noise=0 when there is only an mroot. This is due to how we xor out
  the current mdir cksum during an mdir commit.

  Fixed by using gcksum_p instead of gcksum.

- Added missing LFS3_I_REVDBG/REVNOISE flags in the tests, so now you
  can actually run the tests with LFS3_REVDBG/REVNOISE (this probably
  just fell out-of-date at some point).

---

Curiously, despite LFS3_REVDBG/REVNOISE being disabled by default, this
did save some code. I'm guessing the non-tail-call mtree/gbmap commit
functions prevented some level of inlining?:

                 code          stack          ctx
  before:       35964           2280          660
  after:        35964 (+0.0%)   2280 (+0.0%)  660 (+0.0%)

                 code          stack          ctx
  gbmap before: 38940           2296          772
  gbmap after:  38828 (-0.3%)   2296 (+0.0%)  772 (+0.0%)
This commit is contained in:
Christopher Haster
2025-11-10 00:35:46 -06:00
parent e196be53df
commit 673fa7876f
7 changed files with 353 additions and 229 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tests/test_mount.toml
+36 -18
View File
@@ -30,9 +30,8 @@ defines.COMPACTMETA = [false, true]
defines.CKMETA = [false, true]
defines.CKDATA = [false, true]
if = [
'LFS3_IFDEF_REVDBG(true, !REVDBG)',
'LFS3_IFDEF_REVNOISE(true, !REVNOISE)',
'!REVDBG || !REVNOISE',
'LFS3_IFDEF_YES_REVDBG(REVDBG, LFS3_IFDEF_REVDBG(true, !REVDBG))',
'LFS3_IFDEF_YES_REVNOISE(REVNOISE, LFS3_IFDEF_REVNOISE(true, !REVNOISE))',
'LFS3_IFDEF_CKPROGS(true, !CKPROGS)',
'LFS3_IFDEF_CKFETCHES(true, !CKFETCHES)',
'LFS3_IFDEF_CKMETAPARITY(true, !CKMETAPARITY)',
@@ -77,8 +76,8 @@ code = '''
((RDONLY) ? LFS3_I_RDONLY : 0)
| ((FLUSH) ? LFS3_I_FLUSH : 0)
| ((SYNC) ? LFS3_I_SYNC : 0)
| ((REVDBG) ? LFS3_IFDEF_REVDBG(LFS3_M_REVDBG, -1) : 0)
| ((REVNOISE) ? LFS3_IFDEF_REVNOISE(LFS3_M_REVNOISE, -1) : 0)
| ((REVDBG) ? LFS3_IFDEF_REVDBG(LFS3_I_REVDBG, -1) : 0)
| ((REVNOISE) ? LFS3_IFDEF_REVNOISE(LFS3_I_REVNOISE, -1) : 0)
| ((CKPROGS) ? LFS3_IFDEF_CKPROGS(LFS3_I_CKPROGS, -1) : 0)
| ((CKFETCHES) ? LFS3_IFDEF_CKFETCHES(LFS3_I_CKFETCHES, -1) : 0)
| ((CKMETAPARITY)
@@ -112,9 +111,8 @@ defines.CKMETA = [false, true]
defines.CKDATA = [false, true]
defines.GBMAP = [false, true]
if = [
'LFS3_IFDEF_REVDBG(true, !REVDBG)',
'LFS3_IFDEF_REVNOISE(true, !REVNOISE)',
'!REVDBG || !REVNOISE',
'LFS3_IFDEF_YES_REVDBG(REVDBG, LFS3_IFDEF_REVDBG(true, !REVDBG))',
'LFS3_IFDEF_YES_REVNOISE(REVNOISE, LFS3_IFDEF_REVNOISE(true, !REVNOISE))',
'LFS3_IFDEF_CKPROGS(true, !CKPROGS)',
'LFS3_IFDEF_CKFETCHES(true, !CKFETCHES)',
'LFS3_IFDEF_CKMETAPARITY(true, !CKMETAPARITY)',
@@ -145,7 +143,9 @@ code = '''
struct lfs3_fsinfo fsinfo;
lfs3_fs_stat(&lfs3, &fsinfo) => 0;
assert(fsinfo.flags == (
LFS3_I_MKCONSISTENT
LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
| LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
| LFS3_I_MKCONSISTENT
| LFS3_I_RELOOKAHEAD
| LFS3_I_COMPACTMETA
| LFS3_I_CKMETA
@@ -172,7 +172,9 @@ code = '''
struct lfs3_fsinfo fsinfo;
lfs3_fs_stat(&lfs3, &fsinfo) => 0;
assert(fsinfo.flags == (
LFS3_I_MKCONSISTENT
LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
| LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
| LFS3_I_MKCONSISTENT
| LFS3_I_RELOOKAHEAD
| LFS3_I_COMPACTMETA
| LFS3_I_CKMETA
@@ -189,7 +191,9 @@ code = '''
CFG) => 0;
lfs3_fs_stat(&lfs3, &fsinfo) => 0;
assert(fsinfo.flags == (
LFS3_I_MKCONSISTENT
LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
| LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
| LFS3_I_MKCONSISTENT
| LFS3_I_COMPACTMETA
// note ckdata implies ckmeta
| ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
@@ -219,7 +223,9 @@ code = '''
struct lfs3_fsinfo fsinfo;
lfs3_fs_stat(&lfs3, &fsinfo) => 0;
assert(fsinfo.flags == (
LFS3_I_MKCONSISTENT
LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
| LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
| LFS3_I_MKCONSISTENT
| LFS3_I_RELOOKAHEAD
| LFS3_I_COMPACTMETA
| LFS3_I_CKMETA
@@ -241,7 +247,9 @@ code = '''
lfs3_mount(&lfs3, LFS3_M_RDWR, CFG) => 0;
lfs3_fs_stat(&lfs3, &fsinfo) => 0;
assert(fsinfo.flags == (
LFS3_I_MKCONSISTENT
LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
| LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
| LFS3_I_MKCONSISTENT
| LFS3_I_RELOOKAHEAD
| LFS3_I_REGBMAP
| LFS3_I_COMPACTMETA
@@ -260,7 +268,9 @@ code = '''
CFG) => 0;
lfs3_fs_stat(&lfs3, &fsinfo) => 0;
assert(fsinfo.flags == (
LFS3_I_MKCONSISTENT
LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
| LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
| LFS3_I_MKCONSISTENT
| LFS3_I_COMPACTMETA
// note ckdata implies ckmeta
| ((!CKMETA && !CKDATA) ? LFS3_I_CKMETA : 0)
@@ -316,7 +326,9 @@ code = '''
struct lfs3_fsinfo fsinfo;
lfs3_fs_stat(&lfs3, &fsinfo) => 0;
assert(fsinfo.flags == (
LFS3_I_MKCONSISTENT
LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
| LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
| LFS3_I_MKCONSISTENT
| LFS3_I_RELOOKAHEAD
| LFS3_IFDEF_YES_GBMAP(
(SIZE >= BLOCK_SIZE/4) ? LFS3_I_REGBMAP : 0,
@@ -337,7 +349,9 @@ code = '''
CFG) => 0;
lfs3_fs_stat(&lfs3, &fsinfo) => 0;
assert(fsinfo.flags == (
LFS3_I_MKCONSISTENT
LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
| LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
| LFS3_I_MKCONSISTENT
| ((!RELOOKAHEAD) ? LFS3_I_RELOOKAHEAD : 0)
| LFS3_IFDEF_YES_GBMAP(
(SIZE >= BLOCK_SIZE/4) ? LFS3_I_REGBMAP : 0,
@@ -426,7 +440,9 @@ code = '''
struct lfs3_fsinfo fsinfo;
lfs3_fs_stat(&lfs3, &fsinfo) => 0;
assert(fsinfo.flags == (
LFS3_I_MKCONSISTENT
LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
| LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
| LFS3_I_MKCONSISTENT
| LFS3_I_RELOOKAHEAD
| LFS3_IFDEF_YES_GBMAP(
(ORPHANS >= 100) ? LFS3_I_REGBMAP : 0,
@@ -448,7 +464,9 @@ code = '''
CFG) => 0;
lfs3_fs_stat(&lfs3, &fsinfo) => 0;
assert(fsinfo.flags == (
((!RELOOKAHEAD) ? LFS3_I_RELOOKAHEAD : 0)
LFS3_IFDEF_YES_REVDBG(LFS3_I_REVDBG, 0)
| LFS3_IFDEF_YES_REVNOISE(LFS3_I_REVNOISE, 0)
| ((!RELOOKAHEAD) ? LFS3_I_RELOOKAHEAD : 0)
| LFS3_IFDEF_YES_GBMAP(
(ORPHANS >= 100) ? LFS3_I_REGBMAP : 0,
0)