[PATCH 3/8] memtx: pass engine to memory allocation functions

[Vladimir Davydov <vdavydov.dev@gmail.com>]

We need this so that we can force garbage collection when we are short
on memory. There are two such functions: one is used for allocating
index extents, another for allocating tuples. Index allocating function
has an opaque context so we simply reuse it for passing memtx engine to
it. To pass memtx engine to tuple allocating function, we add an opaque
engine specific pointer to tuple_format (engine_data) and set it to
memtx_engine for memtx spaces.
---
 src/box/memtx_bitset.c |  2 +-
 src/box/memtx_engine.c | 13 ++++++++++---
 src/box/memtx_engine.h |  4 +++-
 src/box/memtx_hash.c   |  2 +-
 src/box/memtx_rtree.c  |  2 +-
 src/box/memtx_space.c  |  4 +++-
 src/box/memtx_tree.c   |  5 ++---
 src/box/tuple_format.c |  1 +
 src/box/tuple_format.h |  2 ++
 9 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/box/memtx_bitset.c b/src/box/memtx_bitset.c
index 93b4a00a..e2252169 100644
--- a/src/box/memtx_bitset.c
+++ b/src/box/memtx_bitset.c
@@ -514,7 +514,7 @@ memtx_bitset_index_new(struct memtx_engine *memtx, struct index_def *def)
 	if (index->id_to_tuple == NULL)
 		panic("failed to allocate memtx bitset index");
 	matras_create(index->id_to_tuple, MEMTX_EXTENT_SIZE, sizeof(struct tuple *),
-		      memtx_index_extent_alloc, memtx_index_extent_free, NULL);
+		      memtx_index_extent_alloc, memtx_index_extent_free, memtx);
 
 	index->tuple_to_id = mh_bitset_index_new();
 	if (index->tuple_to_id == NULL)
diff --git a/src/box/memtx_engine.c b/src/box/memtx_engine.c
index 0c5136cf..70478d75 100644
--- a/src/box/memtx_engine.c
+++ b/src/box/memtx_engine.c
@@ -1059,6 +1059,8 @@ memtx_engine_set_max_tuple_size(struct memtx_engine *memtx, size_t max_size)
 struct tuple *
 memtx_tuple_new(struct tuple_format *format, const char *data, const char *end)
 {
+	struct memtx_engine *memtx = (struct memtx_engine *)format->engine_data;
+	(void)memtx;
 	assert(mp_typeof(*data) == MP_ARRAY);
 	size_t tuple_len = end - data;
 	size_t meta_size = tuple_format_meta_size(format);
@@ -1106,6 +1108,8 @@ memtx_tuple_new(struct tuple_format *format, const char *data, const char *end)
 void
 memtx_tuple_delete(struct tuple_format *format, struct tuple *tuple)
 {
+	struct memtx_engine *memtx = (struct memtx_engine *)format->engine_data;
+	(void)memtx;
 	say_debug("%s(%p)", __func__, tuple);
 	assert(tuple->refs == 0);
 #ifndef NDEBUG
@@ -1140,7 +1144,8 @@ struct tuple_format_vtab memtx_tuple_format_vtab = {
 void *
 memtx_index_extent_alloc(void *ctx)
 {
-	(void)ctx;
+	struct memtx_engine *memtx = (struct memtx_engine *)ctx;
+	(void)memtx;
 	if (memtx_index_reserved_extents) {
 		assert(memtx_index_num_reserved_extents > 0);
 		memtx_index_num_reserved_extents--;
@@ -1168,7 +1173,8 @@ memtx_index_extent_alloc(void *ctx)
 void
 memtx_index_extent_free(void *ctx, void *extent)
 {
-	(void)ctx;
+	struct memtx_engine *memtx = (struct memtx_engine *)ctx;
+	(void)memtx;
 	return mempool_free(&memtx_index_extent_pool, extent);
 }
 
@@ -1177,8 +1183,9 @@ memtx_index_extent_free(void *ctx, void *extent)
  * Ensure that next num extent_alloc will succeed w/o an error
  */
 int
-memtx_index_extent_reserve(int num)
+memtx_index_extent_reserve(struct memtx_engine *memtx, int num)
 {
+	(void)memtx;
 	ERROR_INJECT(ERRINJ_INDEX_ALLOC, {
 		/* same error as in mempool_alloc */
 		diag_set(OutOfMemory, MEMTX_EXTENT_SIZE,
diff --git a/src/box/memtx_engine.h b/src/box/memtx_engine.h
index 9f28c268..389314ba 100644
--- a/src/box/memtx_engine.h
+++ b/src/box/memtx_engine.h
@@ -168,12 +168,14 @@ enum {
 
 /**
  * Allocate a block of size MEMTX_EXTENT_SIZE for memtx index
+ * @ctx must point to memtx engine
  */
 void *
 memtx_index_extent_alloc(void *ctx);
 
 /**
  * Free a block previously allocated by memtx_index_extent_alloc
+ * @ctx must point to memtx engine
  */
 void
 memtx_index_extent_free(void *ctx, void *extent);
@@ -183,7 +185,7 @@ memtx_index_extent_free(void *ctx, void *extent);
  * Ensure that next num extent_alloc will succeed w/o an error
  */
 int
-memtx_index_extent_reserve(int num);
+memtx_index_extent_reserve(struct memtx_engine *memtx, int num);
 
 /**
  * Generic implementation of index_vtab::def_change_requires_rebuild,
diff --git a/src/box/memtx_hash.c b/src/box/memtx_hash.c
index 08ba84ad..d672cafe 100644
--- a/src/box/memtx_hash.c
+++ b/src/box/memtx_hash.c
@@ -490,7 +490,7 @@ memtx_hash_index_new(struct memtx_engine *memtx, struct index_def *def)
 
 	light_index_create(hash_table, HASH_INDEX_EXTENT_SIZE,
 			   memtx_index_extent_alloc, memtx_index_extent_free,
-			   NULL, index->base.def->key_def);
+			   memtx, index->base.def->key_def);
 	index->hash_table = hash_table;
 
 	if (def->iid == 0)
diff --git a/src/box/memtx_rtree.c b/src/box/memtx_rtree.c
index baeffa26..d751a9d8 100644
--- a/src/box/memtx_rtree.c
+++ b/src/box/memtx_rtree.c
@@ -370,7 +370,7 @@ memtx_rtree_index_new(struct memtx_engine *memtx, struct index_def *def)
 
 	index->dimension = def->opts.dimension;
 	rtree_init(&index->tree, index->dimension, MEMTX_EXTENT_SIZE,
-		   memtx_index_extent_alloc, memtx_index_extent_free, NULL,
+		   memtx_index_extent_alloc, memtx_index_extent_free, memtx,
 		   distance_type);
 	return index;
 }
diff --git a/src/box/memtx_space.c b/src/box/memtx_space.c
index 7c795b99..3dd97ddf 100644
--- a/src/box/memtx_space.c
+++ b/src/box/memtx_space.c
@@ -229,13 +229,14 @@ int
 memtx_space_replace_all_keys(struct space *space, struct txn_stmt *stmt,
 			     enum dup_replace_mode mode)
 {
+	struct memtx_engine *memtx = (struct memtx_engine *)space->engine;
 	struct tuple *old_tuple = stmt->old_tuple;
 	struct tuple *new_tuple = stmt->new_tuple;
 	/*
 	 * Ensure we have enough slack memory to guarantee
 	 * successful statement-level rollback.
 	 */
-	if (memtx_index_extent_reserve(new_tuple ?
+	if (memtx_index_extent_reserve(memtx, new_tuple != NULL ?
 				       RESERVE_EXTENTS_BEFORE_REPLACE :
 				       RESERVE_EXTENTS_BEFORE_DELETE) != 0)
 		return -1;
@@ -894,6 +895,7 @@ memtx_space_new(struct memtx_engine *memtx,
 		free(memtx_space);
 		return NULL;
 	}
+	format->engine_data = memtx;
 	format->exact_field_count = def->exact_field_count;
 	tuple_format_ref(format);
 
diff --git a/src/box/memtx_tree.c b/src/box/memtx_tree.c
index 0911af52..8814b13b 100644
--- a/src/box/memtx_tree.c
+++ b/src/box/memtx_tree.c
@@ -688,9 +688,8 @@ memtx_tree_index_new(struct memtx_engine *memtx, struct index_def *def)
 	}
 
 	struct key_def *cmp_def = memtx_tree_index_cmp_def(index);
-	memtx_tree_create(&index->tree, cmp_def,
-			  memtx_index_extent_alloc,
-			  memtx_index_extent_free, NULL);
+	memtx_tree_create(&index->tree, cmp_def, memtx_index_extent_alloc,
+			  memtx_index_extent_free, memtx);
 
 	if (def->iid == 0)
 		index->gc_task.func = memtx_tree_index_destroy_f;
diff --git a/src/box/tuple_format.c b/src/box/tuple_format.c
index d21477f8..bee71e4f 100644
--- a/src/box/tuple_format.c
+++ b/src/box/tuple_format.c
@@ -268,6 +268,7 @@ tuple_format_new(struct tuple_format_vtab *vtab, struct key_def * const *keys,
 	if (format == NULL)
 		return NULL;
 	format->vtab = *vtab;
+	format->engine_data = NULL;
 	format->extra_size = extra_size;
 	if (tuple_format_register(format) < 0) {
 		tuple_format_destroy(format);
diff --git a/src/box/tuple_format.h b/src/box/tuple_format.h
index 08c91a1a..3775b484 100644
--- a/src/box/tuple_format.h
+++ b/src/box/tuple_format.h
@@ -117,6 +117,8 @@ struct tuple_field {
 struct tuple_format {
 	/** Virtual function table */
 	struct tuple_format_vtab vtab;
+	/** Pointer to engine-specific data. */
+	void *engine_data;
 	/** Identifier */
 	uint16_t id;
 	/** Reference counter */
-- 
2.11.0