diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/sys/metaslab_impl.h | 32 | ||||
| -rw-r--r-- | include/sys/space_map.h | 7 |
2 files changed, 29 insertions, 10 deletions
diff --git a/include/sys/metaslab_impl.h b/include/sys/metaslab_impl.h index 386f6240c..a36baedd4 100644 --- a/include/sys/metaslab_impl.h +++ b/include/sys/metaslab_impl.h @@ -67,20 +67,38 @@ struct metaslab_group { }; /* - * Each metaslab's free space is tracked in space map object in the MOS, - * which is only updated in syncing context. Each time we sync a txg, + * Each metaslab maintains an in-core free map (ms_map) that contains the + * current list of free segments. As blocks are allocated, the allocated + * segment is removed from the ms_map and added to a per txg allocation map. + * As blocks are freed, they are added to the per txg free map. These per + * txg maps allow us to process all allocations and frees in syncing context + * where it is safe to update the on-disk space maps. + * + * Each metaslab's free space is tracked in a space map object in the MOS, + * which is only updated in syncing context. Each time we sync a txg, * we append the allocs and frees from that txg to the space map object. * When the txg is done syncing, metaslab_sync_done() updates ms_smo - * to ms_smo_syncing. Everything in ms_smo is always safe to allocate. + * to ms_smo_syncing. Everything in ms_smo is always safe to allocate. + * + * To load the in-core free map we read the space map object from disk. + * This object contains a series of alloc and free records that are + * combined to make up the list of all free segments in this metaslab. These + * segments are represented in-core by the ms_map and are stored in an + * AVL tree. + * + * As the space map objects grows (as a result of the appends) it will + * eventually become space-inefficient. When the space map object is + * zfs_condense_pct/100 times the size of the minimal on-disk representation, + * we rewrite it in its minimized form. */ struct metaslab { kmutex_t ms_lock; /* metaslab lock */ space_map_obj_t ms_smo; /* synced space map object */ space_map_obj_t ms_smo_syncing; /* syncing space map object */ - space_map_t ms_allocmap[TXG_SIZE]; /* allocated this txg */ - space_map_t ms_freemap[TXG_SIZE]; /* freed this txg */ - space_map_t ms_defermap[TXG_DEFER_SIZE]; /* deferred frees */ - space_map_t ms_map; /* in-core free space map */ + space_map_t *ms_allocmap[TXG_SIZE]; /* allocated this txg */ + space_map_t *ms_freemap[TXG_SIZE]; /* freed this txg */ + space_map_t *ms_defermap[TXG_DEFER_SIZE]; /* deferred frees */ + space_map_t *ms_map; /* in-core free space map */ int64_t ms_deferspace; /* sum of ms_defermap[] space */ uint64_t ms_weight; /* weight vs. others in group */ metaslab_group_t *ms_group; /* metaslab group */ diff --git a/include/sys/space_map.h b/include/sys/space_map.h index cbe75afd1..2da80d29b 100644 --- a/include/sys/space_map.h +++ b/include/sys/space_map.h @@ -40,17 +40,17 @@ extern "C" { typedef const struct space_map_ops space_map_ops_t; typedef struct space_map { - avl_tree_t sm_root; /* AVL tree of map segments */ + avl_tree_t sm_root; /* offset-ordered segment AVL tree */ uint64_t sm_space; /* sum of all segments in the map */ uint64_t sm_start; /* start of map */ uint64_t sm_size; /* size of map */ uint8_t sm_shift; /* unit shift */ - uint8_t sm_pad[3]; /* unused */ uint8_t sm_loaded; /* map loaded? */ uint8_t sm_loading; /* map loading? */ + uint8_t sm_condensing; /* map condensing? */ kcondvar_t sm_load_cv; /* map load completion */ space_map_ops_t *sm_ops; /* space map block picker ops vector */ - avl_tree_t *sm_pp_root; /* picker-private AVL tree */ + avl_tree_t *sm_pp_root; /* size-ordered, picker-private tree */ void *sm_ppd; /* picker-private data */ kmutex_t *sm_lock; /* pointer to lock that protects map */ } space_map_t; @@ -149,6 +149,7 @@ extern void space_map_add(space_map_t *sm, uint64_t start, uint64_t size); extern void space_map_remove(space_map_t *sm, uint64_t start, uint64_t size); extern boolean_t space_map_contains(space_map_t *sm, uint64_t start, uint64_t size); +extern void space_map_swap(space_map_t **msrc, space_map_t **mdest); extern void space_map_vacate(space_map_t *sm, space_map_func_t *func, space_map_t *mdest); extern void space_map_walk(space_map_t *sm, |