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Revert back to single typed linked-list for opened mdirs

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While the multi per-type linked-lists were cool and could save RAM in
some structs (at the cost of RAM in the lfs_t struct), this is simpler,
and simpler is good.

The motivation to revert:

1. I noticed most file types have some sort of flags: files,
   traversals (future), (not dirs but maybe in the future). These flags
   can be merged with the type field to give us typed mdirs at almost
   no RAM cost.

2. Using a single linked-list makes it cheaper to add more file types,
   which may be useful for managing bookmarks (differently) and scratch
   files.

   This comes at a runtime cost, since all scans look at all opened
   structs, but we really, _really_ don't care about a constant non-IO
   runtime cost.

There are code benefits, since we don't need nested iterators to access
all opened mdirs, but also some code cost when we want to filter by
type. As expected stack took a small hit. Humorously, the struct savings
in lfs_t perfectly canceled out the struct hit to lfsr_dir_t:

            code          stack          structs
  before:  32992           2968             1080
  after:   33004 (+0.0%)   2976 (+0.3%)     1080 (+0.0%)
This commit is contained in:
Christopher Haster
2024-01-10 12:16:13 -06:00
parent da726c1376
commit dfdf109505
3 changed files with 312 additions and 346 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tests/test_mtree.toml
+76 -76
View File
@@ -2293,12 +2293,12 @@ code = '''
// this test only works if these all fit in the mroot
assert(lfsr_mtree_ismptr(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=2, .rbyd=lfs.mroot.rbyd}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_opened_t left_neighbor = {
.type=0, .mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_opened_t right_neighbor = {
.type=0, .mdir={.mid=2, .rbyd=lfs.mroot.rbyd}};
lfsr_addopened(&lfs, &left_neighbor);
lfsr_addopened(&lfs, &right_neighbor);
// insert a new entry, this should update our neighbors
lfsr_mdir_commit(&lfs, &lfs.mroot, LFSR_ATTRS(
@@ -2320,8 +2320,8 @@ code = '''
assert(memcmp(&right_neighbor.mdir.rbyd, &lfs.mroot.rbyd,
sizeof(lfs.mroot.rbyd)) == 0);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_removeopened(&lfs, &left_neighbor);
lfsr_removeopened(&lfs, &right_neighbor);
lfsr_unmount(&lfs) => 0;
'''
@@ -2340,12 +2340,12 @@ code = '''
// this test only works if these all fit in the mroot
assert(lfsr_mtree_ismptr(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=2, .rbyd=lfs.mroot.rbyd}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_opened_t left_neighbor = {
.type=0, .mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_opened_t right_neighbor = {
.type=0, .mdir={.mid=2, .rbyd=lfs.mroot.rbyd}};
lfsr_addopened(&lfs, &left_neighbor);
lfsr_addopened(&lfs, &right_neighbor);
// try removing our left entry
lfsr_mdir_commit(&lfs, &lfs.mroot, LFSR_ATTRS(
@@ -2360,8 +2360,8 @@ code = '''
assert(memcmp(&right_neighbor.mdir.rbyd, &lfs.mroot.rbyd,
sizeof(lfs.mroot.rbyd)) == 0);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_removeopened(&lfs, &left_neighbor);
lfsr_removeopened(&lfs, &right_neighbor);
lfsr_unmount(&lfs) => 0;
'''
@@ -2380,12 +2380,12 @@ code = '''
// this test only works if these all fit in the mroot
assert(lfsr_mtree_ismptr(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=2, .rbyd=lfs.mroot.rbyd}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_opened_t left_neighbor = {
.type=0, .mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_opened_t right_neighbor = {
.type=0, .mdir={.mid=2, .rbyd=lfs.mroot.rbyd}};
lfsr_addopened(&lfs, &left_neighbor);
lfsr_addopened(&lfs, &right_neighbor);
// try removing our right entry
lfsr_mdir_commit(&lfs, &lfs.mroot, LFSR_ATTRS(
@@ -2400,8 +2400,8 @@ code = '''
sizeof(lfs.mroot.rbyd)) == 0);
assert(right_neighbor.mdir.mid == -1);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_removeopened(&lfs, &left_neighbor);
lfsr_removeopened(&lfs, &right_neighbor);
lfsr_unmount(&lfs) => 0;
'''
@@ -2422,12 +2422,12 @@ code = '''
// this test only works if these all fit in the mroot
assert(lfsr_mtree_ismptr(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=0, .rbyd=lfs.mroot.rbyd}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_opened_t left_neighbor = {
.type=0, .mdir={.mid=0, .rbyd=lfs.mroot.rbyd}};
lfsr_opened_t right_neighbor = {
.type=0, .mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_addopened(&lfs, &left_neighbor);
lfsr_addopened(&lfs, &right_neighbor);
// prepare mroot with a large attr so the next entry can not fit
uint8_t buffer[SIZE];
@@ -2477,8 +2477,8 @@ code = '''
assert(memcmp(&right_neighbor.mdir.rbyd, &msibling.rbyd,
sizeof(msibling.rbyd)) == 0);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_removeopened(&lfs, &left_neighbor);
lfsr_removeopened(&lfs, &right_neighbor);
lfsr_unmount(&lfs) => 0;
'''
@@ -2499,12 +2499,12 @@ code = '''
// this test only works if these all fit in the mroot
assert(lfsr_mtree_ismptr(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=0, .rbyd=lfs.mroot.rbyd}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_opened_t left_neighbor = {
.type=0, .mdir={.mid=0, .rbyd=lfs.mroot.rbyd}};
lfsr_opened_t right_neighbor = {
.type=0, .mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_addopened(&lfs, &left_neighbor);
lfsr_addopened(&lfs, &right_neighbor);
// create 2 large entries that needs to be uninlined and split
uint8_t buffer[SIZE];
@@ -2549,8 +2549,8 @@ code = '''
assert(memcmp(&right_neighbor.mdir.rbyd, &msibling.rbyd,
sizeof(msibling.rbyd)) == 0);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_removeopened(&lfs, &left_neighbor);
lfsr_removeopened(&lfs, &right_neighbor);
lfsr_unmount(&lfs) => 0;
'''
@@ -2598,12 +2598,12 @@ code = '''
assert(lfsr_mtree_weight(&lfs) == 1*lfsr_mweight(&lfs));
assert(mdir.rbyd.weight == 3);
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=mdir.mid+0, .rbyd=mdir.rbyd}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=mdir.mid+2, .rbyd=mdir.rbyd}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_opened_t left_neighbor = {
.type=0, .mdir={.mid=mdir.mid+0, .rbyd=mdir.rbyd}};
lfsr_opened_t right_neighbor = {
.type=0, .mdir={.mid=mdir.mid+2, .rbyd=mdir.rbyd}};
lfsr_addopened(&lfs, &left_neighbor);
lfsr_addopened(&lfs, &right_neighbor);
// now add another large entry to the mdir, forcing a split
memset(buffer, 'e', SIZE);
@@ -2648,8 +2648,8 @@ code = '''
assert(memcmp(&right_neighbor.mdir.rbyd, &msibling.rbyd,
sizeof(msibling.rbyd)) == 0);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_removeopened(&lfs, &left_neighbor);
lfsr_removeopened(&lfs, &right_neighbor);
lfsr_unmount(&lfs) => 0;
'''
@@ -2672,12 +2672,12 @@ code = '''
// this test only works if these all fit in the mroot
assert(lfsr_mtree_ismptr(&lfs));
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=0, .rbyd=lfs.mroot.rbyd}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_opened_t left_neighbor = {
.type=0, .mdir={.mid=0, .rbyd=lfs.mroot.rbyd}};
lfsr_opened_t right_neighbor = {
.type=0, .mdir={.mid=1, .rbyd=lfs.mroot.rbyd}};
lfsr_addopened(&lfs, &left_neighbor);
lfsr_addopened(&lfs, &right_neighbor);
// prepare mroot with an attr
uint8_t buffer[SIZE];
@@ -2711,8 +2711,8 @@ code = '''
assert(memcmp(&right_neighbor.mdir.rbyd, &lfs.mroot.rbyd,
sizeof(lfs.mroot.rbyd)) == 0);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_removeopened(&lfs, &left_neighbor);
lfsr_removeopened(&lfs, &right_neighbor);
lfsr_unmount(&lfs) => 0;
'''
@@ -2762,12 +2762,12 @@ code = '''
assert(lfsr_mtree_weight(&lfs) == 1*lfsr_mweight(&lfs));
assert(mdir.rbyd.weight == 3);
lfsr_openedmdir_t left_neighbor = {
.mdir={.mid=mdir.mid+0, .rbyd=mdir.rbyd}};
lfsr_openedmdir_t right_neighbor = {
.mdir={.mid=mdir.mid+2, .rbyd=mdir.rbyd}};
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_opened_t left_neighbor = {
.type=0, .mdir={.mid=mdir.mid+0, .rbyd=mdir.rbyd}};
lfsr_opened_t right_neighbor = {
.type=0, .mdir={.mid=mdir.mid+2, .rbyd=mdir.rbyd}};
lfsr_addopened(&lfs, &left_neighbor);
lfsr_addopened(&lfs, &right_neighbor);
// force mdir to compact twice, this should relocate
lfsr_mdir_t old_mdir = mdir;
@@ -2803,8 +2803,8 @@ code = '''
assert(memcmp(&right_neighbor.mdir.rbyd, &mdir.rbyd,
sizeof(mdir.rbyd)) == 0);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_removeopened(&lfs, &left_neighbor);
lfsr_removeopened(&lfs, &right_neighbor);
lfsr_unmount(&lfs) => 0;
'''
@@ -2857,18 +2857,18 @@ code = '''
//// Now test splitting updates mids correctly
// setup our neighbors
lfsr_openedmdir_t left_neighbor;
lfsr_opened_t left_neighbor = {.type=0};
lfsr_mtree_lookup(&lfs, 0*lfsr_mweight(&lfs)+0,
&left_neighbor.mdir) => 0;
assert(left_neighbor.mdir.rbyd.weight == 1);
lfsr_openedmdir_t right_neighbor;
lfsr_opened_t right_neighbor = {.type=0};
lfsr_mtree_lookup(&lfs, 2*lfsr_mweight(&lfs)+0,
&right_neighbor.mdir) => 0;
assert(right_neighbor.mdir.rbyd.weight == 1);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_addopened(&lfs, &left_neighbor);
lfsr_addopened(&lfs, &right_neighbor);
// cause middle mdir to split
lfsr_mtree_lookup(&lfs, 1*lfsr_mweight(&lfs)+1, &mdir) => 0;
@@ -2895,8 +2895,8 @@ code = '''
assert(memcmp(&right_neighbor.mdir.rbyd, &mdir.rbyd,
sizeof(mdir.rbyd)) == 0);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_removeopened(&lfs, &left_neighbor);
lfsr_removeopened(&lfs, &right_neighbor);
lfsr_unmount(&lfs) => 0;
'''
@@ -2949,18 +2949,18 @@ code = '''
//// Now test dropping updates mids correctly
// setup our neighbors
lfsr_openedmdir_t left_neighbor;
lfsr_opened_t left_neighbor = {.type=0};
lfsr_mtree_lookup(&lfs, 0*lfsr_mweight(&lfs)+0,
&left_neighbor.mdir) => 0;
assert(left_neighbor.mdir.rbyd.weight == 1);
lfsr_openedmdir_t right_neighbor;
lfsr_opened_t right_neighbor = {.type=0};
lfsr_mtree_lookup(&lfs, 2*lfsr_mweight(&lfs)+0,
&right_neighbor.mdir) => 0;
assert(right_neighbor.mdir.rbyd.weight == 1);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_addopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_addopened(&lfs, &left_neighbor);
lfsr_addopened(&lfs, &right_neighbor);
// cause middle mdir to drop
lfsr_mtree_lookup(&lfs, 1*lfsr_mweight(&lfs)+0, &mdir) => 0;
@@ -2982,8 +2982,8 @@ code = '''
assert(memcmp(&right_neighbor.mdir.rbyd, &mdir.rbyd,
sizeof(mdir.rbyd)) == 0);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &left_neighbor);
lfsr_mdir_removeopened(&lfs, LFS_TYPE_INTERNAL, &right_neighbor);
lfsr_removeopened(&lfs, &left_neighbor);
lfsr_removeopened(&lfs, &right_neighbor);
lfsr_unmount(&lfs) => 0;
'''