From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Vladimir Davydov Subject: [PATCH 09/13] memtx: enter small delayed free mode from snapshot iterator Date: Sat, 10 Aug 2019 13:03:36 +0300 Message-Id: <916ffc0f334fc6c4f176af1fa85cd68072c17d0d.1565430177.git.vdavydov.dev@gmail.com> In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit To: tarantool-patches@freelists.org List-ID: We must enable SMALL_DELAYED_FREE_MODE to safely use a memtx snapshot iterator. Currently, we do that in checkpoint related callbacks, but if we want to reuse snapshot iterators for other purposes, e.g. feeding a read view to a newly joined replica, we better hide this code behind snapshot iterator constructors. --- src/box/memtx_engine.c | 24 ++++++++++++++++-------- src/box/memtx_engine.h | 23 +++++++++++++++++++++++ src/box/memtx_hash.c | 3 +++ src/box/memtx_tree.c | 3 +++ 4 files changed, 45 insertions(+), 8 deletions(-) diff --git a/src/box/memtx_engine.c b/src/box/memtx_engine.c index 87806775..c92ed82b 100644 --- a/src/box/memtx_engine.c +++ b/src/box/memtx_engine.c @@ -614,10 +614,6 @@ memtx_engine_begin_checkpoint(struct engine *engine) memtx->checkpoint = NULL; return -1; } - - /* increment snapshot version; set tuple deletion to delayed mode */ - memtx->snapshot_version++; - small_alloc_setopt(&memtx->alloc, SMALL_DELAYED_FREE_MODE, true); return 0; } @@ -665,8 +661,6 @@ memtx_engine_commit_checkpoint(struct engine *engine, /* waitCheckpoint() must have been done. */ assert(!memtx->checkpoint->waiting_for_snap_thread); - small_alloc_setopt(&memtx->alloc, SMALL_DELAYED_FREE_MODE, false); - if (!memtx->checkpoint->touch) { int64_t lsn = vclock_sum(&memtx->checkpoint->vclock); struct xdir *dir = &memtx->checkpoint->dir; @@ -707,8 +701,6 @@ memtx_engine_abort_checkpoint(struct engine *engine) memtx->checkpoint->waiting_for_snap_thread = false; } - small_alloc_setopt(&memtx->alloc, SMALL_DELAYED_FREE_MODE, false); - /** Remove garbage .inprogress file. */ const char *filename = xdir_format_filename(&memtx->checkpoint->dir, @@ -1018,6 +1010,22 @@ memtx_engine_set_max_tuple_size(struct memtx_engine *memtx, size_t max_size) memtx->max_tuple_size = max_size; } +void +memtx_enter_delayed_free_mode(struct memtx_engine *memtx) +{ + memtx->snapshot_version++; + if (memtx->delayed_free_mode++ == 0) + small_alloc_setopt(&memtx->alloc, SMALL_DELAYED_FREE_MODE, true); +} + +void +memtx_leave_delayed_free_mode(struct memtx_engine *memtx) +{ + assert(memtx->delayed_free_mode > 0); + if (--memtx->delayed_free_mode == 0) + small_alloc_setopt(&memtx->alloc, SMALL_DELAYED_FREE_MODE, false); +} + struct tuple * memtx_tuple_new(struct tuple_format *format, const char *data, const char *end) { diff --git a/src/box/memtx_engine.h b/src/box/memtx_engine.h index ccb51678..c092f5d8 100644 --- a/src/box/memtx_engine.h +++ b/src/box/memtx_engine.h @@ -137,6 +137,12 @@ struct memtx_engine { size_t max_tuple_size; /** Incremented with each next snapshot. */ uint32_t snapshot_version; + /** + * Unless zero, freeing of tuples allocated before the last + * call to memtx_enter_delayed_free_mode() is delayed until + * memtx_leave_delayed_free_mode() is called. + */ + uint32_t delayed_free_mode; /** Memory pool for rtree index iterator. */ struct mempool rtree_iterator_pool; /** @@ -205,6 +211,23 @@ memtx_engine_set_memory(struct memtx_engine *memtx, size_t size); void memtx_engine_set_max_tuple_size(struct memtx_engine *memtx, size_t max_size); +/** + * Enter tuple delayed free mode: tuple allocated before the call + * won't be freed until memtx_leave_delayed_free_mode() is called. + * This function is reentrant, meaning it's okay to call it multiple + * times from the same or different fibers - one just has to leave + * the delayed free mode the same amount of times then. + */ +void +memtx_enter_delayed_free_mode(struct memtx_engine *memtx); + +/** + * Leave tuple delayed free mode. This function undoes the effect + * of memtx_enter_delayed_free_mode(). + */ +void +memtx_leave_delayed_free_mode(struct memtx_engine *memtx); + /** Allocate a memtx tuple. @sa tuple_new(). */ struct tuple * memtx_tuple_new(struct tuple_format *format, const char *data, const char *end); diff --git a/src/box/memtx_hash.c b/src/box/memtx_hash.c index 920f1032..cdd531cb 100644 --- a/src/box/memtx_hash.c +++ b/src/box/memtx_hash.c @@ -414,6 +414,8 @@ hash_snapshot_iterator_free(struct snapshot_iterator *iterator) assert(iterator->free == hash_snapshot_iterator_free); struct hash_snapshot_iterator *it = (struct hash_snapshot_iterator *) iterator; + memtx_leave_delayed_free_mode((struct memtx_engine *) + it->index->base.engine); light_index_iterator_destroy(&it->index->hash_table, &it->iterator); index_unref(&it->index->base); free(iterator); @@ -465,6 +467,7 @@ memtx_hash_index_create_snapshot_iterator(struct index *base) index_ref(base); light_index_iterator_begin(&index->hash_table, &it->iterator); light_index_iterator_freeze(&index->hash_table, &it->iterator); + memtx_enter_delayed_free_mode((struct memtx_engine *)base->engine); return (struct snapshot_iterator *) it; } diff --git a/src/box/memtx_tree.c b/src/box/memtx_tree.c index 831a2715..e155ecd6 100644 --- a/src/box/memtx_tree.c +++ b/src/box/memtx_tree.c @@ -1215,6 +1215,8 @@ tree_snapshot_iterator_free(struct snapshot_iterator *iterator) assert(iterator->free == tree_snapshot_iterator_free); struct tree_snapshot_iterator *it = (struct tree_snapshot_iterator *)iterator; + memtx_leave_delayed_free_mode((struct memtx_engine *) + it->index->base.engine); memtx_tree_iterator_destroy(&it->index->tree, &it->tree_iterator); index_unref(&it->index->base); free(iterator); @@ -1262,6 +1264,7 @@ memtx_tree_index_create_snapshot_iterator(struct index *base) index_ref(base); it->tree_iterator = memtx_tree_iterator_first(&index->tree); memtx_tree_iterator_freeze(&index->tree, &it->tree_iterator); + memtx_enter_delayed_free_mode((struct memtx_engine *)base->engine); return (struct snapshot_iterator *) it; } -- 2.20.1