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Unionized mtree traversal's tortoise state and btree traversal state

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Realistically, because our btree is protected by CoW checksums, the only
place we can end up with a cycle is in our mroot chain.

This is convenient, as we don't need our btree traversal state when
traversing the mroot chain, so we can put both the tortoise state and
btree traversal state into a union, theoretically saving some RAM.

Unfortunately stack measurements show no change, even though our mtree
traversal in on the hot path. I'm not sure why this is. My best guess is
that the RAM savings is beneath the compilation noise floor, since we
currently only ever create one of these structs.
This commit is contained in:
Christopher Haster
2023-08-10 13:50:58 -05:00
parent 0449b06506
commit f1f1a5aaf8
3 changed files with 72 additions and 63 deletions
Download Patch File Download Diff File Expand all files Collapse all files
tests/test_btree.toml
+2 -2
View File
@@ -3852,7 +3852,7 @@ code = '''
uint8_t *seen = malloc((BLOCK_COUNT+7)/8);
memset(seen, 0, (BLOCK_COUNT+7)/8);
lfsr_btree_traversal_t traversal = LFSR_BTREE_TRAVERSAL_INIT;
lfsr_btree_traversal_t traversal = LFSR_BTREE_TRAVERSAL;
for (lfs_block_t i = 0;; i++) {
// a bit hacky, but this catches infinite loops
@@ -4000,7 +4000,7 @@ code = '''
uint8_t *seen = malloc((BLOCK_COUNT+7)/8);
memset(seen, 0, (BLOCK_COUNT+7)/8);
lfsr_btree_traversal_t traversal = LFSR_BTREE_TRAVERSAL_INIT;
lfsr_btree_traversal_t traversal = LFSR_BTREE_TRAVERSAL;
for (lfs_block_t i = 0;; i++) {
// a bit hacky, but this catches infinite loops
tests/test_mtree.toml
+7 -7
View File
@@ -3476,7 +3476,7 @@ code = '''
uint8_t *seen = malloc((BLOCK_COUNT+7)/8);
memset(seen, 0, (BLOCK_COUNT+7)/8);
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL_INIT(
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL(
VALIDATE ? LFSR_MTREE_TRAVERSAL_VALIDATE : 0);
for (lfs_block_t i = 0;; i++) {
@@ -3601,7 +3601,7 @@ code = '''
uint8_t *seen = malloc((BLOCK_COUNT+7)/8);
memset(seen, 0, (BLOCK_COUNT+7)/8);
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL_INIT(
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL(
VALIDATE ? LFSR_MTREE_TRAVERSAL_VALIDATE : 0);
for (lfs_block_t i = 0;; i++) {
@@ -3737,7 +3737,7 @@ code = '''
uint8_t *seen = malloc((BLOCK_COUNT+7)/8);
memset(seen, 0, (BLOCK_COUNT+7)/8);
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL_INIT(
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL(
VALIDATE ? LFSR_MTREE_TRAVERSAL_VALIDATE : 0);
for (lfs_block_t i = 0;; i++) {
@@ -3865,7 +3865,7 @@ code = '''
uint8_t *seen = malloc((BLOCK_COUNT+7)/8);
memset(seen, 0, (BLOCK_COUNT+7)/8);
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL_INIT(
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL(
VALIDATE ? LFSR_MTREE_TRAVERSAL_VALIDATE : 0);
for (lfs_block_t i = 0;; i++) {
@@ -4002,7 +4002,7 @@ code = '''
uint8_t *seen = malloc((BLOCK_COUNT+7)/8);
memset(seen, 0, (BLOCK_COUNT+7)/8);
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL_INIT(
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL(
VALIDATE ? LFSR_MTREE_TRAVERSAL_VALIDATE : 0);
for (lfs_block_t i = 0;; i++) {
@@ -4166,7 +4166,7 @@ code = '''
uint8_t *seen = malloc((BLOCK_COUNT+7)/8);
memset(seen, 0, (BLOCK_COUNT+7)/8);
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL_INIT(
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL(
VALIDATE ? LFSR_MTREE_TRAVERSAL_VALIDATE : 0);
for (lfs_block_t i = 0;; i++) {
@@ -4273,7 +4273,7 @@ code = '''
LFSR_ATTR(-1, MROOT, 0, BUF(buffer, d)))) => 0;
// technically, cycle detection only needs to work when we're validating
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL_INIT(
lfsr_mtree_traversal_t traversal = LFSR_MTREE_TRAVERSAL(
LFSR_MTREE_TRAVERSAL_VALIDATE);
for (lfs_block_t i = 0;; i++) {