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Reverted to separately tracked dir pos/bookmark mdirs

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This is just too enticing a simplification to avoid, even at a RAM cost.

By tracking the dir's bookmark as a separate mdir, we can trivially
deduplicate the logic to update dirs' mdirs. But this does significantly
increase the size of our lfsr_dir_t with the bookmark's type/flags/rbyd/
etc, which usually goes unused.

I guess this does optimize lfsr_dir_rewind... Is that ever a bottleneck?

Code changes:

            code          stack          lfsr_dir_t
  before:  34048           2944                  48
  after:   33956 (-0.3%)   2944 (+0.0%)          80 (+66.7%)
This commit is contained in:
Christopher Haster
2024-01-19 01:39:46 -06:00
parent 76ccefcc84
commit d2a6a6ee2f
2 changed files with 49 additions and 85 deletions
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lfs.c
+42 -77
View File
@@ -6693,12 +6693,16 @@ static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir,
// adjust dir position?
if (opened->type == LFS_TYPE_DIR) {
((lfsr_dir_t*)opened)->pos += attrs[i].delta;
} else if (opened->type == LFS_TYPE_BOOKMARK) {
((lfsr_dir_t*)(opened-1))->pos -= attrs[i].delta;
}
}
} else if (opened->mdir.mid > mdir->mid) {
// adjust dir position?
if (opened->type == LFS_TYPE_DIR) {
((lfsr_dir_t*)opened)->pos += attrs[i].delta;
} else if (opened->type == LFS_TYPE_BOOKMARK) {
((lfsr_dir_t*)(opened-1))->pos -= attrs[i].delta;
}
}
}
@@ -6717,47 +6721,6 @@ static int lfsr_mdir_commit(lfs_t *lfs, lfsr_mdir_t *mdir,
} else if (opened->mdir.mid > mdir->mid) {
opened->mdir.mid += mdelta;
}
if (opened->type == LFS_TYPE_DIR) {
// update any changes to directory bookmarks/positions, this
// gets a bit tricky
lfsr_dir_t *dir = (lfsr_dir_t*)opened;
for (lfs_size_t i = 0; i < attr_count; i++) {
// TODO clean this up a bit?
// adjust opened mdirs?
if (lfsr_mid_bid(lfs, dir->bookmark)
== lfsr_mid_bid(lfs, lfs_smax32(mdir->mid, 0))
&& dir->bookmark >= attrs[i].rid) {
// removed?
if (dir->bookmark < attrs[i].rid - attrs[i].delta) {
// mark dir as dropped
dir->mdir.mid = -1;
dir->bookmark = -1;
goto next;
} else {
dir->bookmark += attrs[i].delta;
// adjust dir position?
dir->pos -= attrs[i].delta;
}
} else if (dir->bookmark > mdir->mid) {
// adjust dir position?
dir->pos -= attrs[i].delta;
}
}
if (lfsr_mid_bid(lfs, dir->bookmark)
== lfsr_mid_bid(lfs, lfs_smax32(mdir->mid, 0))) {
if (mdelta > 0
&& lfsr_mid_rid(lfs, dir->bookmark)
>= mdir_.rbyd.weight) {
dir->bookmark += lfsr_mweight(lfs)
- mdir_.rbyd.weight;
}
} else if (dir->bookmark > mdir->mid) {
dir->bookmark += mdelta;
}
}
next:;
}
// update mdir to follow requested rid
@@ -6967,12 +6930,6 @@ static int lfsr_mtree_pathlookup(lfs_t *lfs, const char *path,
// found end of path, we must be done parsing our path now
if (path[0] == '\0') {
// the root dir doesn't have an mdir really, so it's always
// a special case
if (mdir.mid == -1) {
return LFS_ERR_INVAL;
}
if (mdir_) {
*mdir_ = mdir;
}
@@ -6988,7 +6945,11 @@ static int lfsr_mtree_pathlookup(lfs_t *lfs, const char *path,
if (name_size_) {
*name_size_ = name_size;
}
return LFS_ERR_EXIST;
// the root dir doesn't have an mdir really, so it's always
// a special case
return (mdir.mid == -1)
? LFS_ERR_INVAL
: LFS_ERR_EXIST;
}
// found another name
@@ -8862,6 +8823,12 @@ int lfsr_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
}
int lfsr_dir_open(lfs_t *lfs, lfsr_dir_t *dir, const char *path) {
// setup dir state
dir->p.type = LFS_TYPE_DIR;
dir->p.flags = 0;
dir->b.type = LFS_TYPE_BOOKMARK;
dir->b.flags = 0;
// lookup our directory
lfsr_mdir_t mdir;
lfsr_tag_t tag;
@@ -8899,28 +8866,36 @@ int lfsr_dir_open(lfs_t *lfs, lfsr_dir_t *dir, const char *path) {
}
}
// let rewind initialize the pos/bookmark state
dir->bookmark = 0;
// lookup our bookmark in the mtree
err = lfsr_mtree_namelookup(lfs, dir->did, NULL, 0,
&dir->b.mdir, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// let rewind initialize the pos state
err = lfsr_dir_rewind(lfs, dir);
if (err) {
return err;
}
// add to tracked mdirs
dir->type = LFS_TYPE_DIR;
lfsr_addopened(lfs, (lfsr_opened_t*)dir);
lfsr_addopened(lfs, &dir->p);
lfsr_addopened(lfs, &dir->b);
return 0;
}
int lfsr_dir_close(lfs_t *lfs, lfsr_dir_t *dir) {
// remove from tracked mdirs
lfsr_removeopened(lfs, (lfsr_opened_t*)dir);
lfsr_removeopened(lfs, &dir->p);
lfsr_removeopened(lfs, &dir->b);
return 0;
}
int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
// was our dir removed?
if (dir->bookmark == -1) {
if (lfsr_f_iszombie(dir->b.flags)) {
return LFS_ERR_NOENT;
}
@@ -8938,7 +8913,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
}
// seek in case our mdir was dropped
int err = lfsr_mtree_seek(lfs, &dir->mdir, 0);
int err = lfsr_mtree_seek(lfs, &dir->p.mdir, 0);
if (err) {
return err;
}
@@ -8947,8 +8922,8 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
// lookup the next name tag
lfsr_tag_t tag;
lfsr_data_t data;
err = lfsr_mdir_lookupwide(lfs, &dir->mdir,
dir->mdir.mid, LFSR_TAG_NAME,
err = lfsr_mdir_lookupwide(lfs, &dir->p.mdir,
dir->p.mdir.mid, LFSR_TAG_NAME,
&tag, &data);
if (err) {
return err;
@@ -8969,7 +8944,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
// skip orphans, we pretend these don't exist
if (tag != LFSR_TAG_ORPHAN) {
// fill out our info struct
err = lfsr_stat_(lfs, &dir->mdir, tag, data,
err = lfsr_stat_(lfs, &dir->p.mdir, tag, data,
info);
if (err) {
return err;
@@ -8977,7 +8952,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
}
// eagerly look up the next entry
err = lfsr_mtree_seek(lfs, &dir->mdir, 1);
err = lfsr_mtree_seek(lfs, &dir->p.mdir, 1);
if (err && err != LFS_ERR_NOENT) {
return err;
}
@@ -8991,7 +8966,7 @@ int lfsr_dir_read(lfs_t *lfs, lfsr_dir_t *dir, struct lfs_info *info) {
int lfsr_dir_seek(lfs_t *lfs, lfsr_dir_t *dir, lfs_soff_t off) {
// do nothing if removed
if (dir->bookmark == -1) {
if (lfsr_f_iszombie(dir->b.flags)) {
return 0;
}
@@ -9006,7 +8981,7 @@ int lfsr_dir_seek(lfs_t *lfs, lfsr_dir_t *dir, lfs_soff_t off) {
//
// note the -2 to adjust for dot entries
if (off > 2) {
err = lfsr_mtree_seek(lfs, &dir->mdir, off - 2);
err = lfsr_mtree_seek(lfs, &dir->p.mdir, off - 2);
if (err && err != LFS_ERR_NOENT) {
return err;
}
@@ -9023,26 +8998,16 @@ lfs_soff_t lfsr_dir_tell(lfs_t *lfs, lfsr_dir_t *dir) {
int lfsr_dir_rewind(lfs_t *lfs, lfsr_dir_t *dir) {
// do nothing if removed
if (dir->bookmark == -1) {
if (lfsr_f_iszombie(dir->b.flags)) {
return 0;
}
// lookup our bookmark in the mtree
int err = lfsr_mtree_namelookup(lfs, dir->did, NULL, 0,
&dir->mdir, NULL, NULL);
if (err) {
LFS_ASSERT(err != LFS_ERR_NOENT);
return err;
}
// keep track of bookmark so we can adjust pos correctly
dir->bookmark = dir->mdir.mid;
// reset pos
dir->pos = 0;
// eagerly lookup the next entry
//
// this makes handling of corner cases with mixed removes/dir reads easier
err = lfsr_mtree_seek(lfs, &dir->mdir, 1);
// copy bookmark mdir and eagerly lookup the next entry
dir->p.mdir = dir->b.mdir;
int err = lfsr_mtree_seek(lfs, &dir->p.mdir, 1);
if (err && err != LFS_ERR_NOENT) {
return err;
}
@@ -9196,6 +9161,7 @@ int lfsr_file_opencfg(lfs_t *lfs, lfsr_file_t *file,
}
// setup file state
file->type = LFS_TYPE_REG;
file->flags = flags;
file->cfg = cfg;
file->pos = 0;
@@ -9332,7 +9298,6 @@ int lfsr_file_opencfg(lfs_t *lfs, lfsr_file_t *file,
}
// add to tracked mdirs
file->type = LFS_TYPE_REG;
lfsr_addopened(lfs, (lfsr_opened_t*)file);
return 0;
lfs.h
+7 -8
View File
@@ -116,8 +116,11 @@ enum lfs_error {
// File types
enum lfs_type {
// file types
LFS_TYPE_REG = 1,
LFS_TYPE_DIR = 2,
LFS_TYPE_REG = 1,
LFS_TYPE_DIR = 2,
// internally used types
LFS_TYPE_BOOKMARK = 4,
};
// File open flags
@@ -449,13 +452,9 @@ typedef struct lfs_dir {
} lfs_dir_t;
typedef struct lfsr_dir {
struct lfsr_opened *next;
uint8_t type;
uint16_t flags; // unused
lfsr_mdir_t mdir;
lfsr_opened_t p; // pos mdir
lfsr_opened_t b; // bookmark mdir
lfsr_did_t did;
lfsr_smid_t bookmark;
lfs_soff_t pos;
} lfsr_dir_t;