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t: Changed mtinfo/btinfo to refer to mdirs/rbyds by pointer

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This solves the issue of multiple mdirs/rbyds in lfsr_mtree_gc, where
it's easy for traversal state to fall out of sync when mutating parts of
the filesystem.

Is it good design, with self-referential pointers making everything more
entangled? Not sure!

This saves a bit of stack, but adds a bit of code, which makes sense,
pointer chasing can be costly. But both of these changes are well below
the compiler noise floor:

           code          stack
  before: 35228           2688
  after:  35256 (+0.1%)   2680 (-0.3%)
This commit is contained in:
Christopher Haster
2024-07-04 02:10:40 -05:00
parent bfc108c1dc
commit 3c7b462659
5 changed files with 152 additions and 155 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tests/test_traversal.toml
+10 -10
View File
@@ -6082,7 +6082,7 @@ code = '''
assert(mtinfo.tag == LFSR_TAG_MDIR);
lfsr_mtree_traverse(&lfs, &mt, &mtinfo) => 0;
assert(mtinfo.tag == LFSR_TAG_BRANCH);
if (lfsr_rbyd_eoff(&mtinfo.u.rbyd) > GC_COMPACT_THRESH) {
if (lfsr_rbyd_eoff(mtinfo.u.rbyd) > GC_COMPACT_THRESH) {
break;
}
@@ -6140,7 +6140,7 @@ code = '''
assert(mtinfo.tag == LFSR_TAG_MDIR);
lfsr_mtree_traverse(&lfs, &mt, &mtinfo) => 0;
assert(mtinfo.tag == LFSR_TAG_BRANCH);
assert(lfsr_rbyd_eoff(&mtinfo.u.rbyd) <= GC_COMPACT_THRESH);
assert(lfsr_rbyd_eoff(mtinfo.u.rbyd) <= GC_COMPACT_THRESH);
// check we can still read the files
for (int remount = 0; remount < 2; remount++) {
@@ -6560,7 +6560,7 @@ code = '''
assert(mtinfo.tag == LFSR_TAG_MDIR);
lfsr_mtree_traverse(&lfs, &mt, &mtinfo) => 0;
assert(mtinfo.tag == LFSR_TAG_BRANCH);
if (lfsr_rbyd_eoff(&mtinfo.u.rbyd) > GC_COMPACT_THRESH) {
if (lfsr_rbyd_eoff(mtinfo.u.rbyd) > GC_COMPACT_THRESH) {
break;
}
@@ -6610,7 +6610,7 @@ code = '''
break;
}
assert(mtinfo.tag == LFSR_TAG_BRANCH);
assert(lfsr_rbyd_eoff(&mtinfo.u.rbyd) <= GC_COMPACT_THRESH);
assert(lfsr_rbyd_eoff(mtinfo.u.rbyd) <= GC_COMPACT_THRESH);
}
// check we can still read the file
@@ -6673,7 +6673,7 @@ code = '''
assert(mtinfo.tag == LFSR_TAG_MDIR);
lfsr_mtree_traverse(&lfs, &mt, &mtinfo) => 0;
assert(mtinfo.tag == LFSR_TAG_BRANCH);
if (lfsr_rbyd_eoff(&mtinfo.u.rbyd) > GC_COMPACT_THRESH) {
if (lfsr_rbyd_eoff(mtinfo.u.rbyd) > GC_COMPACT_THRESH) {
break;
}
@@ -6723,7 +6723,7 @@ code = '''
break;
}
assert(mtinfo.tag == LFSR_TAG_BRANCH);
assert(lfsr_rbyd_eoff(&mtinfo.u.rbyd) <= GC_COMPACT_THRESH);
assert(lfsr_rbyd_eoff(mtinfo.u.rbyd) <= GC_COMPACT_THRESH);
}
// check we can still read the file
@@ -6787,7 +6787,7 @@ code = '''
assert(mtinfo.tag == LFSR_TAG_MDIR);
lfsr_mtree_traverse(&lfs, &mt, &mtinfo) => 0;
assert(mtinfo.tag == LFSR_TAG_BRANCH);
if (lfsr_rbyd_eoff(&mtinfo.u.rbyd) > GC_COMPACT_THRESH) {
if (lfsr_rbyd_eoff(mtinfo.u.rbyd) > GC_COMPACT_THRESH) {
break;
}
@@ -6835,7 +6835,7 @@ code = '''
break;
}
assert(mtinfo.tag == LFSR_TAG_BRANCH);
assert(lfsr_rbyd_eoff(&mtinfo.u.rbyd) <= GC_COMPACT_THRESH);
assert(lfsr_rbyd_eoff(mtinfo.u.rbyd) <= GC_COMPACT_THRESH);
}
// check we can still read the file
@@ -6899,7 +6899,7 @@ code = '''
assert(mtinfo.tag == LFSR_TAG_MDIR);
lfsr_mtree_traverse(&lfs, &mt, &mtinfo) => 0;
assert(mtinfo.tag == LFSR_TAG_BRANCH);
if (lfsr_rbyd_eoff(&mtinfo.u.rbyd) > GC_COMPACT_THRESH) {
if (lfsr_rbyd_eoff(mtinfo.u.rbyd) > GC_COMPACT_THRESH) {
break;
}
@@ -6968,7 +6968,7 @@ code = '''
break;
}
assert(mtinfo.tag == LFSR_TAG_BRANCH);
assert(lfsr_rbyd_eoff(&mtinfo.u.rbyd) <= GC_COMPACT_THRESH);
assert(lfsr_rbyd_eoff(mtinfo.u.rbyd) <= GC_COMPACT_THRESH);
}
// check we can still read the files