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tdb: use same expansion factor logic when expanding for new recovery area.

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If we're expanding because the current recovery area is too small, we
expand only the amount we need.  This can quickly lead to exponential
growth when we have a slowly-expanding record (hence a
slowly-expanding transaction size).

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2011-12-21 14:17:16 +10:30
parent c23f1ee0c9
commit 3a2a755e33
3 changed files with 35 additions and 22 deletions
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50
lib/tdb/common/io.c
View File

@ -313,12 +313,39 @@ static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t ad
}
/* You need 'size', this tells you how much you should expand by. */
tdb_off_t tdb_expand_adjust(tdb_off_t map_size, tdb_off_t size, int page_size)
{
tdb_off_t new_size, top_size;
/* limit size in order to avoid using up huge amounts of memory for
* in memory tdbs if an oddball huge record creeps in */
if (size > 100 * 1024) {
top_size = map_size + size * 2;
} else {
top_size = map_size + size * 100;
}
/* always make room for at least top_size more records, and at
least 25% more space. if the DB is smaller than 100MiB,
otherwise grow it by 10% only. */
if (map_size > 100 * 1024 * 1024) {
new_size = map_size * 1.10;
} else {
new_size = map_size * 1.25;
}
/* Round the database up to a multiple of the page size */
new_size = MAX(top_size, new_size);
return TDB_ALIGN(new_size, page_size) - map_size;
}
/* expand the database at least size bytes by expanding the underlying
file and doing the mmap again if necessary */
int tdb_expand(struct tdb_context *tdb, tdb_off_t size)
{
struct tdb_record rec;
tdb_off_t offset, new_size, top_size, map_size;
tdb_off_t offset;
if (tdb_lock(tdb, -1, F_WRLCK) == -1) {
TDB_LOG((tdb, TDB_DEBUG_ERROR, "lock failed in tdb_expand\n"));
@ -328,26 +355,7 @@ int tdb_expand(struct tdb_context *tdb, tdb_off_t size)
/* must know about any previous expansions by another process */
tdb->methods->tdb_oob(tdb, tdb->map_size, 1, 1);
/* limit size in order to avoid using up huge amounts of memory for
* in memory tdbs if an oddball huge record creeps in */
if (size > 100 * 1024) {
top_size = tdb->map_size + size * 2;
} else {
top_size = tdb->map_size + size * 100;
}
/* always make room for at least top_size more records, and at
least 25% more space. if the DB is smaller than 100MiB,
otherwise grow it by 10% only. */
if (tdb->map_size > 100 * 1024 * 1024) {
map_size = tdb->map_size * 1.10;
} else {
map_size = tdb->map_size * 1.25;
}
/* Round the database up to a multiple of the page size */
new_size = MAX(top_size, map_size);
size = TDB_ALIGN(new_size, tdb->page_size) - tdb->map_size;
size = tdb_expand_adjust(tdb->map_size, size, tdb->page_size);
if (!(tdb->flags & TDB_INTERNAL))
tdb_munmap(tdb);

1
lib/tdb/common/tdb_private.h
View File

@ -271,6 +271,7 @@ tdb_off_t tdb_find_lock_hash(struct tdb_context *tdb, TDB_DATA key, uint32_t has
struct tdb_record *rec);
void tdb_io_init(struct tdb_context *tdb);
int tdb_expand(struct tdb_context *tdb, tdb_off_t size);
tdb_off_t tdb_expand_adjust(tdb_off_t map_size, tdb_off_t size, int page_size);
int tdb_rec_free_read(struct tdb_context *tdb, tdb_off_t off,
struct tdb_record *rec);
bool tdb_write_all(int fd, const void *buf, size_t count);

6
lib/tdb/common/transaction.c
View File

@ -730,7 +730,11 @@ static int tdb_recovery_allocate(struct tdb_context *tdb,
*recovery_size = tdb_recovery_size(tdb);
/* round up to a multiple of page size */
*recovery_max_size = TDB_ALIGN(sizeof(rec) + *recovery_size, tdb->page_size) - sizeof(rec);
*recovery_max_size = tdb_expand_adjust(tdb->map_size,
*recovery_size,
tdb->page_size)
- sizeof(rec);
*recovery_offset = tdb->map_size;
recovery_head = *recovery_offset;