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

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>

diff --git a/lib/tdb/common/io.c b/lib/tdb/common/io.c
index a2db3bf4bd81d45f40c42bc6c51c5f2fb31cc159..ac21e3f67a1b00c30f0cb354e72a46ca52a015ac 100644 (file)
--- a/lib/tdb/common/io.c
+++ b/lib/tdb/common/io.c
@@ -313,41 +313,49 @@ static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t ad
 }
 
 
-/* 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)
+/* 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)
 {
-       struct tdb_record rec;
-       tdb_off_t offset, new_size, top_size, map_size;
-
-       if (tdb_lock(tdb, -1, F_WRLCK) == -1) {
-               TDB_LOG((tdb, TDB_DEBUG_ERROR, "lock failed in tdb_expand\n"));
-               return -1;
-       }
-
-       /* must know about any previous expansions by another process */
-       tdb->methods->tdb_oob(tdb, tdb->map_size, 1, 1);
+       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 = tdb->map_size + size * 2;
+               top_size = map_size + size * 2;
        } else {
-               top_size = tdb->map_size + size * 100;
+               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 (tdb->map_size > 100 * 1024 * 1024) {
-               map_size = tdb->map_size * 1.10;
+       if (map_size > 100 * 1024 * 1024) {
+               new_size = map_size * 1.10;
        } else {
-               map_size = tdb->map_size * 1.25;
+               new_size = 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;
+       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;
+
+       if (tdb_lock(tdb, -1, F_WRLCK) == -1) {
+               TDB_LOG((tdb, TDB_DEBUG_ERROR, "lock failed in tdb_expand\n"));
+               return -1;
+       }
+
+       /* must know about any previous expansions by another process */
+       tdb->methods->tdb_oob(tdb, tdb->map_size, 1, 1);
+
+       size = tdb_expand_adjust(tdb->map_size, size, tdb->page_size);
 
        if (!(tdb->flags & TDB_INTERNAL))
                tdb_munmap(tdb);

diff --git a/lib/tdb/common/tdb_private.h b/lib/tdb/common/tdb_private.h
index 3c6aabffc76a7c244df9a29d42f9003b54cac3dd..4fc7381aa041201d87ae815d715f25e861e53b4e 100644 (file)
--- a/lib/tdb/common/tdb_private.h
+++ b/lib/tdb/common/tdb_private.h
@@ -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);

diff --git a/lib/tdb/common/transaction.c b/lib/tdb/common/transaction.c
index 66ecbfdefb6ef827681eebaf2bb3230bf0b386b1..f7d56a05a3650315bed4646d6e650c6d62e405d3 100644 (file)
--- a/lib/tdb/common/transaction.c
+++ b/lib/tdb/common/transaction.c
@@ -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;