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

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Vova, please, review.

On 14/11/2018 13:44, imeevma@tarantool.org wrote:
> 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
>