- /*
+ /*
Trivial Database 2: free list/block handling
Copyright (C) Rusty Russell 2010
-
+
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
return bucket;
}
-int tdb_flist_init(struct tdb_context *tdb)
+tdb_off_t first_ftable(struct tdb_context *tdb)
{
- tdb->flist_off = tdb_read_off(tdb,
- offsetof(struct tdb_header, free_list));
- if (tdb->flist_off == TDB_OFF_ERR)
- return -1;
+ return tdb_read_off(tdb, offsetof(struct tdb_header, free_table));
+}
+
+tdb_off_t next_ftable(struct tdb_context *tdb, tdb_off_t ftable)
+{
+ return tdb_read_off(tdb, ftable + offsetof(struct tdb_freetable,next));
+}
+
+int tdb_ftable_init(struct tdb_context *tdb)
+{
+ /* Use reservoir sampling algorithm to select a free list at random. */
+ unsigned int rnd, max = 0, count = 0;
+ tdb_off_t off;
+
+ tdb->ftable_off = off = first_ftable(tdb);
+ tdb->ftable = 0;
+
+ while (off) {
+ if (off == TDB_OFF_ERR)
+ return -1;
+
+ rnd = random();
+ if (rnd >= max) {
+ tdb->ftable_off = off;
+ tdb->ftable = count;
+ max = rnd;
+ }
+
+ off = next_ftable(tdb, off);
+ count++;
+ }
return 0;
}
/* Offset of a given bucket. */
-tdb_off_t bucket_off(tdb_off_t flist_off, unsigned bucket)
+tdb_off_t bucket_off(tdb_off_t ftable_off, unsigned bucket)
{
- return flist_off + offsetof(struct tdb_freelist, buckets)
+ return ftable_off + offsetof(struct tdb_freetable, buckets)
+ bucket * sizeof(tdb_off_t);
}
/* Returns free_buckets + 1, or list number to search. */
-static tdb_off_t find_free_head(struct tdb_context *tdb, tdb_off_t bucket)
+static tdb_off_t find_free_head(struct tdb_context *tdb,
+ tdb_off_t ftable_off,
+ tdb_off_t bucket)
{
/* Speculatively search for a non-zero bucket. */
- return tdb_find_nonzero_off(tdb, bucket_off(tdb->flist_off, 0),
+ return tdb_find_nonzero_off(tdb, bucket_off(ftable_off, 0),
bucket, TDB_FREE_BUCKETS);
}
/* Remove from free bucket. */
static int remove_from_list(struct tdb_context *tdb,
tdb_off_t b_off, tdb_off_t r_off,
- struct tdb_free_record *r)
+ const struct tdb_free_record *r)
{
tdb_off_t off;
/* Front of list? */
- if (r->prev == 0) {
+ if (frec_prev(r) == 0) {
off = b_off;
} else {
- off = r->prev + offsetof(struct tdb_free_record, next);
+ off = frec_prev(r) + offsetof(struct tdb_free_record, next);
}
-#ifdef DEBUG
+#ifdef CCAN_TDB2_DEBUG
if (tdb_read_off(tdb, off) != r_off) {
- tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
- "remove_from_list: %llu bad prev in list %llu\n",
+ tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
+ "remove_from_list: %llu bad prev in list %llu",
(long long)r_off, (long long)b_off);
return -1;
}
}
if (r->next != 0) {
- off = r->next + offsetof(struct tdb_free_record, prev);
+ off = r->next + offsetof(struct tdb_free_record,magic_and_prev);
/* r->next->prev = r->prev */
-#ifdef DEBUG
- if (tdb_read_off(tdb, off) != r_off) {
- tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
- "remove_from_list: %llu bad list %llu\n",
- (long long)r_off, (long long)b_off);
+#ifdef CCAN_TDB2_DEBUG
+ if (tdb_read_off(tdb, off) & TDB_OFF_MASK != r_off) {
+ tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
+ "remove_from_list: %llu bad list %llu",
+ (long long)r_off, (long long)b_off);
return -1;
}
#endif
- if (tdb_write_off(tdb, off, r->prev)) {
+ if (tdb_write_off(tdb, off, r->magic_and_prev)) {
return -1;
}
}
static int enqueue_in_free(struct tdb_context *tdb,
tdb_off_t b_off,
tdb_off_t off,
- struct tdb_free_record *new)
+ tdb_len_t len)
{
- new->prev = 0;
+ struct tdb_free_record new;
+ uint64_t magic = (TDB_FREE_MAGIC << (64 - TDB_OFF_UPPER_STEAL));
+
+ /* We only need to set ftable_and_len; rest is set in enqueue_in_free */
+ new.ftable_and_len = ((uint64_t)tdb->ftable << (64 - TDB_OFF_UPPER_STEAL))
+ | len;
+ /* prev = 0. */
+ new.magic_and_prev = magic;
+
/* new->next = head. */
- new->next = tdb_read_off(tdb, b_off);
- if (new->next == TDB_OFF_ERR)
+ new.next = tdb_read_off(tdb, b_off);
+ if (new.next == TDB_OFF_ERR)
return -1;
- if (new->next) {
-#ifdef DEBUG
+ if (new.next) {
+#ifdef CCAN_TDB2_DEBUG
if (tdb_read_off(tdb,
- new->next
- + offsetof(struct tdb_free_record, prev))
- != 0) {
- tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
- "enqueue_in_free: %llu bad head prev %llu\n",
- (long long)new->next, (long long)b_off);
+ new.next + offsetof(struct tdb_free_record,
+ magic_and_prev))
+ != magic) {
+ tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
+ "enqueue_in_free: %llu bad head"
+ " prev %llu",
+ (long long)new.next, (long long)b_off);
return -1;
}
#endif
/* next->prev = new. */
- if (tdb_write_off(tdb, new->next
- + offsetof(struct tdb_free_record, prev),
- off) != 0)
+ if (tdb_write_off(tdb, new.next
+ + offsetof(struct tdb_free_record,
+ magic_and_prev),
+ off | magic) != 0)
return -1;
}
/* head = new */
if (tdb_write_off(tdb, b_off, off) != 0)
return -1;
- return tdb_write_convert(tdb, off, new, sizeof(*new));
+ return tdb_write_convert(tdb, off, &new, sizeof(new));
}
/* List need not be locked. */
int add_free_record(struct tdb_context *tdb,
tdb_off_t off, tdb_len_t len_with_header)
{
- struct tdb_free_record new;
tdb_off_t b_off;
+ tdb_len_t len;
int ret;
+ enum TDB_ERROR ecode;
- assert(len_with_header >= sizeof(new));
+ assert(len_with_header >= sizeof(struct tdb_free_record));
- new.magic_and_meta = TDB_FREE_MAGIC;
- new.data_len = len_with_header - sizeof(struct tdb_used_record);
+ len = len_with_header - sizeof(struct tdb_used_record);
- b_off = bucket_off(tdb->flist_off, size_to_bucket(new.data_len));
- if (tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT) != 0)
+ b_off = bucket_off(tdb->ftable_off, size_to_bucket(len));
+ ecode = tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT);
+ if (ecode != TDB_SUCCESS) {
+ tdb->ecode = ecode;
return -1;
+ }
- ret = enqueue_in_free(tdb, b_off, off, &new);
+ ret = enqueue_in_free(tdb, b_off, off, len);
tdb_unlock_free_bucket(tdb, b_off);
return ret;
}
return leftover;
}
+static tdb_off_t ftable_offset(struct tdb_context *tdb, unsigned int ftable)
+{
+ tdb_off_t off;
+ unsigned int i;
+
+ if (likely(tdb->ftable == ftable))
+ return tdb->ftable_off;
+
+ off = first_ftable(tdb);
+ for (i = 0; i < ftable; i++)
+ off = next_ftable(tdb, off);
+ return off;
+}
+
/* Note: we unlock the current bucket if we coalesce or fail. */
static int coalesce(struct tdb_context *tdb,
tdb_off_t off, tdb_off_t b_off, tdb_len_t data_len)
{
- struct tdb_free_record pad, *r;
tdb_off_t end;
+ struct tdb_free_record rec;
+ add_stat(tdb, alloc_coalesce_tried, 1);
end = off + sizeof(struct tdb_used_record) + data_len;
while (end < tdb->map_size) {
+ const struct tdb_free_record *r;
tdb_off_t nb_off;
+ unsigned ftable, bucket;
- /* FIXME: do tdb_get here and below really win? */
- r = tdb_get(tdb, end, &pad, sizeof(pad));
+ r = tdb_access_read(tdb, end, sizeof(*r), true);
if (!r)
goto err;
- if (frec_magic(r) != TDB_FREE_MAGIC)
+ if (frec_magic(r) != TDB_FREE_MAGIC
+ || frec_ftable(r) == TDB_FTABLE_NONE) {
+ tdb_access_release(tdb, r);
break;
+ }
- /* FIXME: Use flist from record */
- nb_off = bucket_off(tdb->flist_off,size_to_bucket(r->data_len));
+ ftable = frec_ftable(r);
+ bucket = size_to_bucket(frec_len(r));
+ nb_off = bucket_off(ftable_offset(tdb, ftable), bucket);
+ tdb_access_release(tdb, r);
/* We may be violating lock order here, so best effort. */
- if (tdb_lock_free_bucket(tdb, nb_off, TDB_LOCK_NOWAIT) == -1)
+ if (tdb_lock_free_bucket(tdb, nb_off, TDB_LOCK_NOWAIT)
+ != TDB_SUCCESS) {
+ add_stat(tdb, alloc_coalesce_lockfail, 1);
break;
+ }
/* Now we have lock, re-check. */
- r = tdb_get(tdb, end, &pad, sizeof(pad));
- if (!r) {
+ if (tdb_read_convert(tdb, end, &rec, sizeof(rec))) {
tdb_unlock_free_bucket(tdb, nb_off);
goto err;
}
- if (unlikely(frec_magic(r) != TDB_FREE_MAGIC)) {
+ if (unlikely(frec_magic(&rec) != TDB_FREE_MAGIC)) {
+ add_stat(tdb, alloc_coalesce_race, 1);
tdb_unlock_free_bucket(tdb, nb_off);
break;
}
- if (unlikely(bucket_off(tdb->flist_off,
- size_to_bucket(r->data_len))
- != nb_off)) {
+ if (unlikely(frec_ftable(&rec) != ftable)
+ || unlikely(size_to_bucket(frec_len(&rec)) != bucket)) {
+ add_stat(tdb, alloc_coalesce_race, 1);
tdb_unlock_free_bucket(tdb, nb_off);
break;
}
- if (remove_from_list(tdb, nb_off, end, r) == -1) {
+ if (remove_from_list(tdb, nb_off, end, &rec) == -1) {
tdb_unlock_free_bucket(tdb, nb_off);
goto err;
}
- end += sizeof(struct tdb_used_record) + r->data_len;
+ end += sizeof(struct tdb_used_record) + frec_len(&rec);
tdb_unlock_free_bucket(tdb, nb_off);
+ add_stat(tdb, alloc_coalesce_num_merged, 1);
}
/* Didn't find any adjacent free? */
if (end == off + sizeof(struct tdb_used_record) + data_len)
return 0;
- /* OK, expand record */
- r = tdb_get(tdb, off, &pad, sizeof(pad));
- if (!r)
+ /* OK, expand initial record */
+ if (tdb_read_convert(tdb, off, &rec, sizeof(rec)))
goto err;
- if (r->data_len != data_len) {
- tdb->ecode = TDB_ERR_CORRUPT;
- tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
- "coalesce: expected data len %llu not %llu\n",
- (long long)data_len, (long long)r->data_len);
+ if (frec_len(&rec) != data_len) {
+ tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
+ "coalesce: expected data len %zu not %zu",
+ (size_t)data_len, (size_t)frec_len(&rec));
goto err;
}
- if (remove_from_list(tdb, b_off, off, r) == -1)
- goto err;
-
- r = tdb_access_write(tdb, off, sizeof(*r), true);
- if (!r)
+ if (remove_from_list(tdb, b_off, off, &rec) == -1)
goto err;
/* We have to drop this to avoid deadlocks, so make sure record
* doesn't get coalesced by someone else! */
- r->magic_and_meta = TDB_COALESCING_MAGIC;
- r->data_len = end - off - sizeof(struct tdb_used_record);
- if (tdb_access_commit(tdb, r) != 0)
+ rec.ftable_and_len = (TDB_FTABLE_NONE << (64 - TDB_OFF_UPPER_STEAL))
+ | (end - off - sizeof(struct tdb_used_record));
+ if (tdb_write_off(tdb, off + offsetof(struct tdb_free_record,
+ ftable_and_len),
+ rec.ftable_and_len) != 0)
goto err;
+ add_stat(tdb, alloc_coalesce_succeeded, 1);
tdb_unlock_free_bucket(tdb, b_off);
if (add_free_record(tdb, off, end - off) == -1)
/* We need size bytes to put our key and data in. */
static tdb_off_t lock_and_alloc(struct tdb_context *tdb,
- tdb_off_t flist_off,
+ tdb_off_t ftable_off,
tdb_off_t bucket,
size_t keylen, size_t datalen,
bool want_extra,
+ unsigned magic,
unsigned hashlow)
{
tdb_off_t off, b_off,best_off;
- struct tdb_free_record pad, best = { 0 }, *r;
+ struct tdb_free_record best = { 0 };
double multiplier;
size_t size = adjust_size(keylen, datalen);
+ enum TDB_ERROR ecode;
+ add_stat(tdb, allocs, 1);
again:
- b_off = bucket_off(flist_off, bucket);
+ b_off = bucket_off(ftable_off, bucket);
/* FIXME: Try non-blocking wait first, to measure contention. */
/* Lock this bucket. */
- if (tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT) == -1) {
+ ecode = tdb_lock_free_bucket(tdb, b_off, TDB_LOCK_WAIT);
+ if (ecode != TDB_SUCCESS) {
+ tdb->ecode = ecode;
return TDB_OFF_ERR;
}
- best.data_len = -1ULL;
+ best.ftable_and_len = -1ULL;
best_off = 0;
/* Get slack if we're after extra. */
goto unlock_err;
while (off) {
- /* FIXME: Does tdb_get win anything here? */
- r = tdb_get(tdb, off, &pad, sizeof(*r));
+ const struct tdb_free_record *r;
+ tdb_len_t len;
+ tdb_off_t next;
+
+ r = tdb_access_read(tdb, off, sizeof(*r), true);
if (!r)
goto unlock_err;
if (frec_magic(r) != TDB_FREE_MAGIC) {
- tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
- "lock_and_alloc: %llu non-free 0x%llx\n",
- (long long)off, (long long)r->magic_and_meta);
+ tdb_access_release(tdb, r);
+ tdb_logerr(tdb, TDB_ERR_CORRUPT, TDB_LOG_ERROR,
+ "lock_and_alloc: %llu non-free 0x%llx",
+ (long long)off, (long long)r->magic_and_prev);
goto unlock_err;
}
- if (r->data_len >= size && r->data_len < best.data_len) {
+ if (frec_len(r) >= size && frec_len(r) < frec_len(&best)) {
best_off = off;
best = *r;
}
- if (best.data_len < size * multiplier && best_off)
+ if (frec_len(&best) < size * multiplier && best_off) {
+ tdb_access_release(tdb, r);
break;
+ }
multiplier *= 1.01;
+ next = r->next;
+ len = frec_len(r);
+ tdb_access_release(tdb, r);
+
/* Since we're going slow anyway, try coalescing here. */
- switch (coalesce(tdb, off, b_off, r->data_len)) {
+ switch (coalesce(tdb, off, b_off, len)) {
case -1:
/* This has already unlocked on error. */
return -1;
/* This has unlocked list, restart. */
goto again;
}
- off = r->next;
+ off = next;
}
/* If we found anything at all, use it. */
goto unlock_err;
leftover = record_leftover(keylen, datalen, want_extra,
- best.data_len);
+ frec_len(&best));
- assert(keylen + datalen + leftover <= best.data_len);
+ assert(keylen + datalen + leftover <= frec_len(&best));
/* We need to mark non-free before we drop lock, otherwise
* coalesce() could try to merge it! */
- if (set_header(tdb, &rec, keylen, datalen,
- best.data_len - leftover,
- hashlow) != 0)
+ if (set_header(tdb, &rec, magic, keylen, datalen,
+ frec_len(&best) - leftover, hashlow) != 0)
goto unlock_err;
if (tdb_write_convert(tdb, best_off, &rec, sizeof(rec)) != 0)
goto unlock_err;
- tdb_unlock_free_bucket(tdb, b_off);
-
+ /* Bucket of leftover will be <= current bucket, so nested
+ * locking is allowed. */
if (leftover) {
+ add_stat(tdb, alloc_leftover, 1);
if (add_free_record(tdb,
best_off + sizeof(rec)
- + best.data_len - leftover,
+ + frec_len(&best) - leftover,
leftover))
- return TDB_OFF_ERR;
+ best_off = TDB_OFF_ERR;
}
+ tdb_unlock_free_bucket(tdb, b_off);
+
return best_off;
}
/* Get a free block from current free list, or 0 if none. */
static tdb_off_t get_free(struct tdb_context *tdb,
size_t keylen, size_t datalen, bool want_extra,
- unsigned hashlow)
+ unsigned magic, unsigned hashlow)
{
- tdb_off_t off;
- unsigned start_b, b;
+ tdb_off_t off, ftable_off;
+ unsigned start_b, b, ftable;
+ bool wrapped = false;
/* If they are growing, add 50% to get to higher bucket. */
if (want_extra)
else
start_b = size_to_bucket(adjust_size(keylen, datalen));
- /* Start at exact size bucket, and search up... */
- for (b = find_free_head(tdb, start_b);
- b < TDB_FREE_BUCKETS;
- b = find_free_head(tdb, b + 1)) {
- /* Try getting one from list. */
- off = lock_and_alloc(tdb, tdb->flist_off,
- b, keylen, datalen, want_extra,
- hashlow);
- if (off == TDB_OFF_ERR)
- return TDB_OFF_ERR;
- if (off != 0)
- return off;
- /* Didn't work. Try next bucket. */
+ ftable_off = tdb->ftable_off;
+ ftable = tdb->ftable;
+ while (!wrapped || ftable_off != tdb->ftable_off) {
+ /* Start at exact size bucket, and search up... */
+ for (b = find_free_head(tdb, ftable_off, start_b);
+ b < TDB_FREE_BUCKETS;
+ b = find_free_head(tdb, ftable_off, b + 1)) {
+ /* Try getting one from list. */
+ off = lock_and_alloc(tdb, ftable_off,
+ b, keylen, datalen, want_extra,
+ magic, hashlow);
+ if (off == TDB_OFF_ERR)
+ return TDB_OFF_ERR;
+ if (off != 0) {
+ if (b == start_b)
+ add_stat(tdb, alloc_bucket_exact, 1);
+ if (b == TDB_FREE_BUCKETS - 1)
+ add_stat(tdb, alloc_bucket_max, 1);
+ /* Worked? Stay using this list. */
+ tdb->ftable_off = ftable_off;
+ tdb->ftable = ftable;
+ return off;
+ }
+ /* Didn't work. Try next bucket. */
+ }
+
+ /* Hmm, try next table. */
+ ftable_off = next_ftable(tdb, ftable_off);
+ ftable++;
+
+ if (ftable_off == 0) {
+ wrapped = true;
+ ftable_off = first_ftable(tdb);
+ ftable = 0;
+ }
}
+
return 0;
}
int set_header(struct tdb_context *tdb,
struct tdb_used_record *rec,
- uint64_t keylen, uint64_t datalen,
+ unsigned magic, uint64_t keylen, uint64_t datalen,
uint64_t actuallen, unsigned hashlow)
{
uint64_t keybits = (fls64(keylen) + 1) / 2;
rec->magic_and_meta = (hashlow & ((1 << 11)-1))
| ((actuallen - (keylen + datalen)) << 11)
| (keybits << 43)
- | (TDB_MAGIC << 48);
+ | ((uint64_t)magic << 48);
rec->key_and_data_len = (keylen | (datalen << (keybits*2)));
/* Encoding can fail on big values. */
if (rec_key_length(rec) != keylen
|| rec_data_length(rec) != datalen
|| rec_extra_padding(rec) != actuallen - (keylen + datalen)) {
- tdb->ecode = TDB_ERR_IO;
- tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
- "Could not encode k=%llu,d=%llu,a=%llu\n",
+ tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
+ "Could not encode k=%llu,d=%llu,a=%llu",
(long long)keylen, (long long)datalen,
(long long)actuallen);
return -1;
{
uint64_t old_size;
tdb_len_t wanted;
+ enum TDB_ERROR ecode;
/* We need room for the record header too. */
wanted = sizeof(struct tdb_used_record) + size;
+ /* Need to hold a hash lock to expand DB: transactions rely on it. */
+ if (!(tdb->flags & TDB_NOLOCK)
+ && !tdb->allrecord_lock.count && !tdb_has_hash_locks(tdb)) {
+ tdb_logerr(tdb, TDB_ERR_LOCK, TDB_LOG_ERROR,
+ "tdb_expand: must hold lock during expand");
+ return -1;
+ }
+
+ /* always make room for at least 100 more records, and at
+ least 25% more space. */
+ if (size * TDB_EXTENSION_FACTOR > tdb->map_size / 4)
+ wanted = size * TDB_EXTENSION_FACTOR;
+ else
+ wanted = tdb->map_size / 4;
+ wanted = adjust_size(0, wanted);
+
/* Only one person can expand file at a time. */
- if (tdb_lock_expand(tdb, F_WRLCK) != 0)
+ ecode = tdb_lock_expand(tdb, F_WRLCK);
+ if (ecode != TDB_SUCCESS) {
+ tdb->ecode = ecode;
return -1;
+ }
/* Someone else may have expanded the file, so retry. */
old_size = tdb->map_size;
return 0;
}
- if (tdb->methods->expand_file(tdb, wanted*TDB_EXTENSION_FACTOR) == -1) {
+ ecode = tdb->methods->expand_file(tdb, wanted);
+ if (ecode != TDB_SUCCESS) {
+ tdb->ecode = ecode;
tdb_unlock_expand(tdb, F_WRLCK);
return -1;
}
/* We need to drop this lock before adding free record. */
tdb_unlock_expand(tdb, F_WRLCK);
- return add_free_record(tdb, old_size, wanted * TDB_EXTENSION_FACTOR);
+ add_stat(tdb, expands, 1);
+ return add_free_record(tdb, old_size, wanted);
}
/* This won't fail: it will expand the database if it has to. */
tdb_off_t alloc(struct tdb_context *tdb, size_t keylen, size_t datalen,
- uint64_t hash, bool growing)
+ uint64_t hash, unsigned magic, bool growing)
{
tdb_off_t off;
assert(!tdb->direct_access);
for (;;) {
- off = get_free(tdb, keylen, datalen, growing, hash);
+ off = get_free(tdb, keylen, datalen, growing, magic, hash);
if (likely(off != 0))
break;
projects / ccan / blobdiff