[tarantool-patches] [PATCH v2 1/1] box: restore region after box.snapshot()

[imeevma@tarantool.org]

Before this patch region wasn't restored after box.snapshot() so
some tests fail due to "memory leak". This patch adds additional
memory management and fixes mentioned failures.

Closes #3732
---
Issue: https://github.com/tarantool/tarantool/issues/assigned/ImeevMA
Branch: https://github.com/tarantool/tarantool/tree/imeevma/gh-3732-additional-memory-managament-in-box_snapshot

 src/box/memtx_engine.c        | 41 ++++++++++++++++++++---------------------
 src/box/vy_log.c              | 11 ++++++++---
 test/engine/snapshot.result   | 35 +++++++++++++++++++++++++++++++++++
 test/engine/snapshot.test.lua | 17 +++++++++++++++++
 4 files changed, 80 insertions(+), 24 deletions(-)

diff --git a/src/box/memtx_engine.c b/src/box/memtx_engine.c
index 5a5e87e..12be0f2 100644
--- a/src/box/memtx_engine.c
+++ b/src/box/memtx_engine.c
@@ -589,28 +589,34 @@ struct checkpoint {
 	bool touch;
 };
 
-static int
-checkpoint_init(struct checkpoint *ckpt, const char *snap_dirname,
-		uint64_t snap_io_rate_limit)
+static struct checkpoint *
+checkpoint_new(const char *snap_dirname, uint64_t snap_io_rate_limit)
 {
+	struct checkpoint *ckpt = malloc(sizeof(*ckpt));
+	if (ckpt == NULL) {
+		diag_set(OutOfMemory, sizeof(*ckpt), "malloc",
+			 "struct checkpoint");
+		return NULL;
+	}
 	rlist_create(&ckpt->entries);
 	ckpt->waiting_for_snap_thread = false;
 	xdir_create(&ckpt->dir, snap_dirname, SNAP, &INSTANCE_UUID);
 	ckpt->snap_io_rate_limit = snap_io_rate_limit;
 	vclock_create(&ckpt->vclock);
 	ckpt->touch = false;
-	return 0;
+	return ckpt;
 }
 
 static void
-checkpoint_destroy(struct checkpoint *ckpt)
+checkpoint_delete(struct checkpoint *ckpt)
 {
 	struct checkpoint_entry *entry;
 	rlist_foreach_entry(entry, &ckpt->entries, link) {
 		entry->iterator->free(entry->iterator);
+		free(entry);
 	}
-	rlist_create(&ckpt->entries);
 	xdir_destroy(&ckpt->dir);
+	free(ckpt);
 }
 
 
@@ -625,11 +631,10 @@ checkpoint_add_space(struct space *sp, void *data)
 	if (!pk)
 		return 0;
 	struct checkpoint *ckpt = (struct checkpoint *)data;
-	struct checkpoint_entry *entry;
-	entry = region_alloc_object(&fiber()->gc, struct checkpoint_entry);
+	struct checkpoint_entry *entry = malloc(sizeof(*entry));
 	if (entry == NULL) {
 		diag_set(OutOfMemory, sizeof(*entry),
-			 "region", "struct checkpoint_entry");
+			 "malloc", "struct checkpoint_entry");
 		return -1;
 	}
 	rlist_add_tail_entry(&ckpt->entries, entry, link);
@@ -693,19 +698,13 @@ memtx_engine_begin_checkpoint(struct engine *engine)
 	struct memtx_engine *memtx = (struct memtx_engine *)engine;
 
 	assert(memtx->checkpoint == NULL);
-	memtx->checkpoint = region_alloc_object(&fiber()->gc, struct checkpoint);
-	if (memtx->checkpoint == NULL) {
-		diag_set(OutOfMemory, sizeof(*memtx->checkpoint),
-			 "region", "struct checkpoint");
-		return -1;
-	}
-
-	if (checkpoint_init(memtx->checkpoint, memtx->snap_dir.dirname,
-			    memtx->snap_io_rate_limit) != 0)
+	memtx->checkpoint = checkpoint_new(memtx->snap_dir.dirname,
+					   memtx->snap_io_rate_limit);
+	if (memtx->checkpoint == NULL)
 		return -1;
 
 	if (space_foreach(checkpoint_add_space, memtx->checkpoint) != 0) {
-		checkpoint_destroy(memtx->checkpoint);
+		checkpoint_delete(memtx->checkpoint);
 		memtx->checkpoint = NULL;
 		return -1;
 	}
@@ -790,7 +789,7 @@ memtx_engine_commit_checkpoint(struct engine *engine,
 		xdir_add_vclock(&memtx->snap_dir, &memtx->checkpoint->vclock);
 	}
 
-	checkpoint_destroy(memtx->checkpoint);
+	checkpoint_delete(memtx->checkpoint);
 	memtx->checkpoint = NULL;
 }
 
@@ -818,7 +817,7 @@ memtx_engine_abort_checkpoint(struct engine *engine)
 				     INPROGRESS);
 	(void) coio_unlink(filename);
 
-	checkpoint_destroy(memtx->checkpoint);
+	checkpoint_delete(memtx->checkpoint);
 	memtx->checkpoint = NULL;
 }
 
diff --git a/src/box/vy_log.c b/src/box/vy_log.c
index fc8ede5..c7ed7cb 100644
--- a/src/box/vy_log.c
+++ b/src/box/vy_log.c
@@ -761,6 +761,7 @@ vy_log_flush(void)
 	stailq_foreach_entry(record, &vy_log.tx, in_tx)
 		tx_size++;
 
+	size_t used = region_used(&fiber()->gc);
 	struct journal_entry *entry = journal_entry_new(tx_size);
 	if (entry == NULL)
 		return -1;
@@ -770,7 +771,7 @@ vy_log_flush(void)
 				    tx_size * sizeof(struct xrow_header),
 				    alignof(struct xrow_header));
 	if (rows == NULL)
-		return -1;
+		goto err;
 
 	/*
 	 * Encode buffered records.
@@ -780,7 +781,7 @@ vy_log_flush(void)
 		assert(i < tx_size);
 		struct xrow_header *row = &rows[i];
 		if (vy_log_record_encode(record, row) < 0)
-			return -1;
+			goto err;
 		entry->rows[i] = row;
 		i++;
 	}
@@ -791,12 +792,16 @@ vy_log_flush(void)
 	 * so as not to block the tx thread.
 	 */
 	if (wal_write_vy_log(entry) != 0)
-		return -1;
+		goto err;
 
+	region_truncate(&fiber()->gc, used);
 	/* Success. Free flushed records. */
 	region_reset(&vy_log.pool);
 	stailq_create(&vy_log.tx);
 	return 0;
+err:
+	region_truncate(&fiber()->gc, used);
+	return -1;
 }
 
 void
diff --git a/test/engine/snapshot.result b/test/engine/snapshot.result
index a5aa08d..42009c2 100644
--- a/test/engine/snapshot.result
+++ b/test/engine/snapshot.result
@@ -238,3 +238,38 @@ box.space.test.index.secondary:select{}
 box.space.test:drop()
 ---
 ...
+--
+-- sql: fix sql/gh-3199-no-mem-leaks.test.lua
+-- One of the reason why this test failed - box.snapshot didn't
+-- free region.
+--
+fiber = require('fiber')
+---
+...
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
+---
+- 0
+...
+box.snapshot()
+---
+- ok
+...
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
+---
+- 0
+...
+box.snapshot()
+---
+- ok
+...
+box.snapshot()
+---
+- ok
+...
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
+---
+- 0
+...
diff --git a/test/engine/snapshot.test.lua b/test/engine/snapshot.test.lua
index 4bbbe40..2a32280 100644
--- a/test/engine/snapshot.test.lua
+++ b/test/engine/snapshot.test.lua
@@ -41,3 +41,20 @@ box.space.test:select{}
 box.space.test.index.primary:select{}
 box.space.test.index.secondary:select{}
 box.space.test:drop()
+
+--
+-- sql: fix sql/gh-3199-no-mem-leaks.test.lua
+-- One of the reason why this test failed - box.snapshot didn't
+-- free region.
+--
+
+fiber = require('fiber')
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
+box.snapshot()
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
+box.snapshot()
+box.snapshot()
+-- Should be 0.
+fiber.info()[fiber.self().id()].memory.used
-- 
2.7.4