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tag-returning: Adopted tag-returns in btree lookups

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- lfs3_btree_lookupleaf
- lfs3_btree_lookupnext
- lfs3_btree_lookup
- lfs3_btree_traverse
- NOT lfs3_btree_namelookup

Looks like we're starting to claw back stack usage a bit. This makes
sense as the btree logic involves the most layers -- with out-pointers
it needs more temporary copies to inspect tags along the way:

           code          stack          ctx
  before: 36576           2376          656
  after:  36520 (-0.2%)   2352 (-1.0%)  656 (+0.0%)
This commit is contained in:
Christopher Haster
2025-07-17 15:11:40 -05:00
parent 8be483d493
commit 100fb66d37
4 changed files with 406 additions and 421 deletions
Download Patch File Download Diff File Expand all files Collapse all files
lfs3.c
+67 -87
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@@ -5239,10 +5239,11 @@ static int lfs3_data_fetchbtree(lfs3_t *lfs3, lfs3_data_t *data,
// lookup rbyd/rid containing a given bid
#ifndef LFS3_2BONLY
static int lfs3_btree_lookupleaf(lfs3_t *lfs3, const lfs3_btree_t *btree,
static lfs3_stag_t lfs3_btree_lookupleaf(lfs3_t *lfs3,
const lfs3_btree_t *btree,
lfs3_bid_t bid,
lfs3_bid_t *bid_, lfs3_rbyd_t *rbyd_, lfs3_srid_t *rid_,
lfs3_tag_t *tag_, lfs3_bid_t *weight_, lfs3_data_t *data_) {
lfs3_bid_t *weight_, lfs3_data_t *data_) {
// descend down the btree looking for our bid
*rbyd_ = *btree;
lfs3_srid_t rid = bid;
@@ -5290,16 +5291,13 @@ static int lfs3_btree_lookupleaf(lfs3_t *lfs3, const lfs3_btree_t *btree,
if (rid_) {
*rid_ = rid__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = weight__;
}
if (data_) {
*data_ = data__;
}
return 0;
return tag__;
}
}
}
@@ -5308,13 +5306,13 @@ static int lfs3_btree_lookupleaf(lfs3_t *lfs3, const lfs3_btree_t *btree,
// non-leaf lookups discard the rbyd info, which can be a bit more
// convenient, but may make commits more costly
#ifndef LFS3_2BONLY
static int lfs3_btree_lookupnext(lfs3_t *lfs3, const lfs3_btree_t *btree,
static lfs3_stag_t lfs3_btree_lookupnext(lfs3_t *lfs3,
const lfs3_btree_t *btree,
lfs3_bid_t bid,
lfs3_bid_t *bid_, lfs3_tag_t *tag_, lfs3_bid_t *weight_,
lfs3_data_t *data_) {
lfs3_bid_t *bid_, lfs3_bid_t *weight_, lfs3_data_t *data_) {
lfs3_rbyd_t rbyd;
return lfs3_btree_lookupleaf(lfs3, btree, bid,
bid_, &rbyd, NULL, tag_, weight_, data_);
bid_, &rbyd, NULL, weight_, data_);
}
#endif
@@ -5322,17 +5320,17 @@ static int lfs3_btree_lookupnext(lfs3_t *lfs3, const lfs3_btree_t *btree,
// behavior, if you don't care about the exact bid either first call
// lfs3_btree_lookupnext, or lfs3_btree_lookupleaf + lfs3_rbyd_lookup
#ifndef LFS3_2BONLY
static int lfs3_btree_lookup(lfs3_t *lfs3, const lfs3_btree_t *btree,
static lfs3_stag_t lfs3_btree_lookup(lfs3_t *lfs3, const lfs3_btree_t *btree,
lfs3_bid_t bid, lfs3_tag_t tag,
lfs3_tag_t *tag_, lfs3_data_t *data_) {
lfs3_data_t *data_) {
// lookup rbyd in btree
lfs3_bid_t bid__;
lfs3_rbyd_t rbyd__;
lfs3_srid_t rid__;
int err = lfs3_btree_lookupleaf(lfs3, btree, bid,
&bid__, &rbyd__, &rid__, NULL, NULL, NULL);
if (err) {
return err;
lfs3_stag_t tag__ = lfs3_btree_lookupleaf(lfs3, btree, bid,
&bid__, &rbyd__, &rid__, NULL, NULL);
if (tag__ < 0) {
return tag__;
}
// lookup finds the next-smallest bid, all we need to do is fail if it
@@ -5342,16 +5340,8 @@ static int lfs3_btree_lookup(lfs3_t *lfs3, const lfs3_btree_t *btree,
}
// lookup tag in rbyd
lfs3_stag_t tag__ = lfs3_rbyd_lookup(lfs3, &rbyd__, rid__, tag,
return lfs3_rbyd_lookup(lfs3, &rbyd__, rid__, tag,
data_);
if (tag__ < 0) {
return tag__;
}
if (tag_) {
*tag_ = tag__;
}
return 0;
}
#endif
@@ -5497,12 +5487,12 @@ static int lfs3_btree_commit_(lfs3_t *lfs3,
lfs3_srid_t rid = bcommit->bid;
if (btree->weight > 0) {
lfs3_srid_t rid_;
int err = lfs3_btree_lookupleaf(lfs3, btree,
lfs3_stag_t tag = lfs3_btree_lookupleaf(lfs3, btree,
lfs3_min(bcommit->bid, btree->weight-1),
&bcommit->bid, &child, &rid_, NULL, NULL, NULL);
if (err) {
LFS3_ASSERT(err != LFS3_ERR_NOENT);
return err;
&bcommit->bid, &child, &rid_, NULL, NULL);
if (tag < 0) {
LFS3_ASSERT(tag != LFS3_ERR_NOENT);
return tag;
}
// adjust rid
@@ -6287,10 +6277,10 @@ static void lfs3_btraversal_init(lfs3_btraversal_t *bt) {
#endif
#ifndef LFS3_2BONLY
static int lfs3_btree_traverse(lfs3_t *lfs3, const lfs3_btree_t *btree,
static lfs3_stag_t lfs3_btree_traverse(lfs3_t *lfs3,
const lfs3_btree_t *btree,
lfs3_btraversal_t *bt,
lfs3_bid_t *bid_, lfs3_tag_t *tag_, lfs3_bid_t *weight_,
lfs3_data_t *data_) {
lfs3_bid_t *bid_, lfs3_bid_t *weight_, lfs3_data_t *data_) {
// explicitly traverse the root even if weight=0
if (!bt->branch) {
bt->branch = btree;
@@ -6305,16 +6295,13 @@ static int lfs3_btree_traverse(lfs3_t *lfs3, const lfs3_btree_t *btree,
if (bid_) {
*bid_ = btree->weight-1;
}
if (tag_) {
*tag_ = LFS3_TAG_BRANCH;
}
if (weight_) {
*weight_ = btree->weight;
}
if (data_) {
data_->u.buffer = (const uint8_t*)bt->branch;
}
return 0;
return LFS3_TAG_BRANCH;
}
}
@@ -6365,16 +6352,13 @@ static int lfs3_btree_traverse(lfs3_t *lfs3, const lfs3_btree_t *btree,
if (bid_) {
*bid_ = bt->bid + (rid__ - bt->rid);
}
if (tag_) {
*tag_ = LFS3_TAG_BRANCH;
}
if (weight_) {
*weight_ = weight__;
}
if (data_) {
data_->u.buffer = (const uint8_t*)bt->branch;
}
return 0;
return LFS3_TAG_BRANCH;
}
// found our bid
@@ -6390,16 +6374,13 @@ static int lfs3_btree_traverse(lfs3_t *lfs3, const lfs3_btree_t *btree,
if (bid_) {
*bid_ = bid__;
}
if (tag_) {
*tag_ = tag__;
}
if (weight_) {
*weight_ = weight__;
}
if (data_) {
*data_ = data__;
}
return 0;
return tag__;
}
}
}
@@ -6725,44 +6706,46 @@ static lfs3_ssize_t lfs3_bshrub_estimate(lfs3_t *lfs3,
// bshrub lookup functions
#ifndef LFS3_2BONLY
static int lfs3_bshrub_lookupleaf(lfs3_t *lfs3, const lfs3_bshrub_t *bshrub,
static lfs3_stag_t lfs3_bshrub_lookupleaf(lfs3_t *lfs3,
const lfs3_bshrub_t *bshrub,
lfs3_bid_t bid,
lfs3_bid_t *bid_, lfs3_rbyd_t *rbyd_, lfs3_srid_t *rid_,
lfs3_tag_t *tag_, lfs3_bid_t *weight_, lfs3_data_t *data_) {
lfs3_bid_t *weight_, lfs3_data_t *data_) {
return lfs3_btree_lookupleaf(lfs3, &bshrub->shrub, bid,
bid_, rbyd_, rid_, tag_, weight_, data_);
bid_, rbyd_, rid_, weight_, data_);
}
#endif
static int lfs3_bshrub_lookupnext(lfs3_t *lfs3, const lfs3_bshrub_t *bshrub,
static lfs3_stag_t lfs3_bshrub_lookupnext(lfs3_t *lfs3,
const lfs3_bshrub_t *bshrub,
lfs3_bid_t bid,
lfs3_bid_t *bid_, lfs3_tag_t *tag_, lfs3_bid_t *weight_,
lfs3_data_t *data_) {
lfs3_bid_t *bid_, lfs3_bid_t *weight_, lfs3_data_t *data_) {
#ifndef LFS3_2BONLY
return lfs3_btree_lookupnext(lfs3, &bshrub->shrub, bid,
bid_, tag_, weight_, data_);
bid_, weight_, data_);
#else
return lfs3_rbyd_lookupnext(lfs3, &bshrub->shrub, bid, 0,
(lfs3_srid_t*)bid_, tag_, weight_, data_);
(lfs3_srid_t*)bid_, weight_, data_);
#endif
}
#ifndef LFS3_2BONLY
static int lfs3_bshrub_lookup(lfs3_t *lfs3, const lfs3_bshrub_t *bshrub,
static lfs3_stag_t lfs3_bshrub_lookup(lfs3_t *lfs3,
const lfs3_bshrub_t *bshrub,
lfs3_bid_t bid, lfs3_tag_t tag,
lfs3_tag_t *tag_, lfs3_data_t *data_) {
lfs3_data_t *data_) {
return lfs3_btree_lookup(lfs3, &bshrub->shrub, bid, tag,
tag_, data_);
data_);
}
#endif
#ifndef LFS3_2BONLY
static int lfs3_bshrub_traverse(lfs3_t *lfs3, const lfs3_bshrub_t *bshrub,
static lfs3_stag_t lfs3_bshrub_traverse(lfs3_t *lfs3,
const lfs3_bshrub_t *bshrub,
lfs3_btraversal_t *bt,
lfs3_bid_t *bid_, lfs3_tag_t *tag_, lfs3_bid_t *weight_,
lfs3_data_t *data_) {
lfs3_bid_t *bid_, lfs3_bid_t *weight_, lfs3_data_t *data_) {
return lfs3_btree_traverse(lfs3, &bshrub->shrub, bt,
bid_, tag_, weight_, data_);
bid_, weight_, data_);
}
#endif
@@ -7976,14 +7959,13 @@ static int lfs3_mtree_lookup(lfs3_t *lfs3, lfs3_smid_t mid,
#ifndef LFS3_2BONLY
lfs3_bid_t bid;
lfs3_srid_t rid;
lfs3_stag_t tag;
lfs3_bid_t weight;
lfs3_data_t data;
int err = lfs3_btree_lookupleaf(lfs3, &lfs3->mtree, mid,
&bid, &mdir_->r, &rid, (lfs3_tag_t*)&tag, &weight, &data);
if (err) {
LFS3_ASSERT(err != LFS3_ERR_NOENT);
return err;
lfs3_stag_t tag = lfs3_btree_lookupleaf(lfs3, &lfs3->mtree, mid,
&bid, &mdir_->r, &rid, &weight, &data);
if (tag < 0) {
LFS3_ASSERT(tag != LFS3_ERR_NOENT);
return tag;
}
LFS3_ASSERT((lfs3_sbid_t)bid == lfs3_mbid(lfs3, mid));
LFS3_ASSERT(weight == (lfs3_bid_t)(1 << lfs3->mbits));
@@ -9790,11 +9772,11 @@ static int lfs3_mtree_traverse_(lfs3_t *lfs3, lfs3_traversal_t *t,
#ifndef LFS3_2BONLY
case LFS3_TSTATE_MROOTCHAIN:;
// lookup mroot, if we find one this is not the active mroot
lfs3_tag_t tag;
lfs3_stag_t tag;
lfs3_data_t data;
err = lfs3_mdir_lookup(lfs3, &t->b.o.mdir,
LFS3_TAG_MASK8 | LFS3_TAG_STRUCT,
&tag, &data);
(lfs3_tag_t*)&tag, &data);
if (err) {
// if we have no mtree (inlined mdir), we need to
// traverse any files in our mroot next
@@ -9970,10 +9952,10 @@ static int lfs3_mtree_traverse_(lfs3_t *lfs3, lfs3_traversal_t *t,
case LFS3_TSTATE_BTREE:;
case LFS3_TSTATE_OBTREE:;
// traverse through our bshrub/btree
err = lfs3_bshrub_traverse(lfs3, &t->b, &t->u.bt,
NULL, &tag, NULL, &data);
if (err) {
if (err == LFS3_ERR_NOENT) {
tag = lfs3_bshrub_traverse(lfs3, &t->b, &t->u.bt,
NULL, NULL, &data);
if (tag < 0) {
if (tag == LFS3_ERR_NOENT) {
// clear the bshrub state
lfs3_bshrub_init(&t->b);
// end of mtree? start iterating over mdirs
@@ -9999,7 +9981,7 @@ static int lfs3_mtree_traverse_(lfs3_t *lfs3, lfs3_traversal_t *t,
LFS3_UNREACHABLE();
}
}
return err;
return tag;
}
// found an inner btree node?
@@ -11971,19 +11953,18 @@ int lfs3_file_close(lfs3_t *lfs3, lfs3_file_t *file) {
static int lfs3_file_lookupnext(lfs3_t *lfs3, const lfs3_file_t *file,
lfs3_bid_t bid,
lfs3_bid_t *bid_, lfs3_bid_t *weight_, lfs3_bptr_t *bptr_) {
lfs3_tag_t tag;
lfs3_bid_t weight;
lfs3_data_t data;
int err = lfs3_bshrub_lookupnext(lfs3, &file->b, bid,
bid_, &tag, &weight, &data);
if (err) {
return err;
lfs3_stag_t tag = lfs3_bshrub_lookupnext(lfs3, &file->b, bid,
bid_, &weight, &data);
if (tag < 0) {
return tag;
}
LFS3_ASSERT(tag == LFS3_TAG_DATA
|| tag == LFS3_TAG_BLOCK);
// fetch the bptr/data fragment
err = lfs3_bptr_fetch(lfs3, bptr_, tag, weight, data);
int err = lfs3_bptr_fetch(lfs3, bptr_, tag, weight, data);
if (err) {
return err;
}
@@ -14095,15 +14076,14 @@ static int lfs3_file_ck(lfs3_t *lfs3, const lfs3_file_t *file,
lfs3_btraversal_t bt;
lfs3_btraversal_init(&bt);
while (true) {
lfs3_tag_t tag;
lfs3_data_t data;
int err = lfs3_bshrub_traverse(lfs3, &file->b, &bt,
NULL, &tag, NULL, &data);
if (err) {
if (err == LFS3_ERR_NOENT) {
lfs3_stag_t tag = lfs3_bshrub_traverse(lfs3, &file->b, &bt,
NULL, NULL, &data);
if (tag < 0) {
if (tag == LFS3_ERR_NOENT) {
break;
}
return err;
return tag;
}
// validate btree nodes?
@@ -14115,7 +14095,7 @@ static int lfs3_file_ck(lfs3_t *lfs3, const lfs3_file_t *file,
|| lfs3_t_isckdata(flags))
&& tag == LFS3_TAG_BRANCH) {
lfs3_rbyd_t *rbyd = (lfs3_rbyd_t*)data.u.buffer;
err = lfs3_rbyd_fetchck(lfs3, rbyd,
int err = lfs3_rbyd_fetchck(lfs3, rbyd,
rbyd->blocks[0], rbyd->trunk,
rbyd->cksum);
if (err) {
@@ -14127,7 +14107,7 @@ static int lfs3_file_ck(lfs3_t *lfs3, const lfs3_file_t *file,
if (lfs3_t_isckdata(flags)
&& tag == LFS3_TAG_BLOCK) {
lfs3_bptr_t bptr;
err = lfs3_data_readbptr(lfs3, &data,
int err = lfs3_data_readbptr(lfs3, &data,
&bptr);
if (err) {
return err;