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* [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell
@ 2012-04-12 22:34 Mike Snitzer
  2012-04-12 22:34 ` [PATCH 2/2] dm thin: use slab_pool for caches Mike Snitzer
  2012-04-23  7:24 ` [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell Joe Thornber
  0 siblings, 2 replies; 6+ messages in thread
From: Mike Snitzer @ 2012-04-12 22:34 UTC (permalink / raw)
  To: dm-devel; +Cc: ejt

Add missing mempool_free() to __cell_release_singleton().

This is a pretty significant leak that will accumulate to over 2GB of
leaked memory just from running the full thinp-test-suite.  Leak was
known to exist but the kmalloc_pool which was used for prison cell
allocation caused all leaked memory to be attributed to the "size-128"
cache.  kmemleak proved useful in identifying the source of this
illusive leak.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm-thin.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Index: linux-2.6/drivers/md/dm-thin.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-thin.c
+++ linux-2.6/drivers/md/dm-thin.c
@@ -279,8 +279,10 @@ static void __cell_release(struct cell *
 
 	hlist_del(&cell->list);
 
-	bio_list_add(inmates, cell->holder);
-	bio_list_merge(inmates, &cell->bios);
+	if (inmates) {
+		bio_list_add(inmates, cell->holder);
+		bio_list_merge(inmates, &cell->bios);
+	}
 
 	mempool_free(cell, prison->cell_pool);
 }
@@ -303,9 +305,10 @@ static void cell_release(struct cell *ce
  */
 static void __cell_release_singleton(struct cell *cell, struct bio *bio)
 {
-	hlist_del(&cell->list);
 	BUG_ON(cell->holder != bio);
 	BUG_ON(!bio_list_empty(&cell->bios));
+
+	__cell_release(cell, NULL);
 }
 
 static void cell_release_singleton(struct cell *cell, struct bio *bio)

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 2/2] dm thin: use slab_pool for caches
  2012-04-12 22:34 [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell Mike Snitzer
@ 2012-04-12 22:34 ` Mike Snitzer
  2012-04-12 22:39   ` [PATCH 2/2 v2] dm thin: use slab mempools with local caches Mike Snitzer
  2012-04-23  7:24 ` [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell Joe Thornber
  1 sibling, 1 reply; 6+ messages in thread
From: Mike Snitzer @ 2012-04-12 22:34 UTC (permalink / raw)
  To: dm-devel; +Cc: ejt

Use dedicated caches prefixed with a "dm_" name rather than rely on
generic slab caches.

This will aid in debugging thinp memory leaks should they occur.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm-thin.c |   52 ++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 47 insertions(+), 5 deletions(-)

Index: linux-2.6/drivers/md/dm-thin.c
===================================================================
--- linux-2.6.orig/drivers/md/dm-thin.c
+++ linux-2.6/drivers/md/dm-thin.c
@@ -141,6 +141,8 @@ static uint32_t calc_nr_buckets(unsigned
 	return n;
 }
 
+struct kmem_cache *_cell_cache;
+
 /*
  * @nr_cells should be the number of cells you want in use _concurrently_.
  * Don't confuse it with the number of distinct keys.
@@ -157,8 +159,7 @@ static struct bio_prison *prison_create(
 		return NULL;
 
 	spin_lock_init(&prison->lock);
-	prison->cell_pool = mempool_create_kmalloc_pool(nr_cells,
-							sizeof(struct cell));
+	prison->cell_pool = mempool_create_slab_pool(nr_cells, _cell_cache);
 	if (!prison->cell_pool) {
 		kfree(prison);
 		return NULL;
@@ -1649,6 +1650,9 @@ static void pool_features_init(struct po
 	pf->discard_passdown = 1;
 }
 
+struct kmem_cache *_new_mapping_cache;
+struct kmem_cache *_endio_hook_cache;
+
 static void __pool_destroy(struct pool *pool)
 {
 	__pool_table_remove(pool);
@@ -1738,7 +1742,7 @@ static struct pool *pool_create(struct m
 
 	pool->next_mapping = NULL;
 	pool->mapping_pool =
-		mempool_create_kmalloc_pool(MAPPING_POOL_SIZE, sizeof(struct new_mapping));
+		mempool_create_slab_pool(MAPPING_POOL_SIZE, _new_mapping_cache);
 	if (!pool->mapping_pool) {
 		*error = "Error creating pool's mapping mempool";
 		err_p = ERR_PTR(-ENOMEM);
@@ -1746,7 +1750,7 @@ static struct pool *pool_create(struct m
 	}
 
 	pool->endio_hook_pool =
-		mempool_create_kmalloc_pool(ENDIO_HOOK_POOL_SIZE, sizeof(struct endio_hook));
+		mempool_create_slab_pool(ENDIO_HOOK_POOL_SIZE, _endio_hook_cache);
 	if (!pool->endio_hook_pool) {
 		*error = "Error creating pool's endio_hook mempool";
 		err_p = ERR_PTR(-ENOMEM);
@@ -2748,7 +2752,42 @@ static int __init dm_thin_init(void)
 
 	r = dm_register_target(&pool_target);
 	if (r)
-		dm_unregister_target(&thin_target);
+		goto bad_pool_target;
+
+	_cell_cache = kmem_cache_create("dm_bio_prison_cell",
+					sizeof(struct cell),
+					__alignof__(struct cell), 0, NULL);
+	if (!_cell_cache) {
+		r = -ENOMEM;
+		goto bad_cell_cache;
+	}
+
+	_new_mapping_cache = kmem_cache_create("dm_thin_new_mapping",
+					       sizeof(struct new_mapping),
+					       __alignof__(struct new_mapping), 0, NULL);
+	if (!_new_mapping_cache) {
+		r = -ENOMEM;
+		goto bad_new_mapping_cache;
+	}
+
+	_endio_hook_cache = kmem_cache_create("dm_thin_endio_hook",
+					      sizeof(struct endio_hook),
+					      __alignof__(struct endio_hook), 0, NULL);
+	if (!_endio_hook_cache) {
+		r = -ENOMEM;
+		goto bad_endio_hook_cache;
+	}
+
+	return 0;
+
+bad_endio_hook_cache:
+	kmem_cache_destroy(_new_mapping_cache);
+bad_new_mapping_cache:
+	kmem_cache_destroy(_cell_cache);
+bad_cell_cache:
+	dm_unregister_target(&pool_target);
+bad_pool_target:
+	dm_unregister_target(&thin_target);
 
 	return r;
 }
@@ -2757,6 +2796,9 @@ static void dm_thin_exit(void)
 {
 	dm_unregister_target(&thin_target);
 	dm_unregister_target(&pool_target);
+	kmem_cache_destroy(_cell_cache);
+	kmem_cache_destroy(_new_mapping_cache);
+	kmem_cache_destroy(_endio_hook_cache);
 }
 
 module_init(dm_thin_init);

^ permalink raw reply	[flat|nested] 6+ messages in thread

* [PATCH 2/2 v2] dm thin: use slab mempools with local caches
  2012-04-12 22:34 ` [PATCH 2/2] dm thin: use slab_pool for caches Mike Snitzer
@ 2012-04-12 22:39   ` Mike Snitzer
  0 siblings, 0 replies; 6+ messages in thread
From: Mike Snitzer @ 2012-04-12 22:39 UTC (permalink / raw)
  To: dm-devel; +Cc: ejt

Use dedicated caches prefixed with a "dm_" name rather than rely on
kmalloc mempools backed by generic slab caches.

This will aid in debugging thinp memory leaks should they occur.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
---
 drivers/md/dm-thin.c |   52 +++++++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 47 insertions(+), 5 deletions(-)

v2: tweaked subject and header some, no code changes.

diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index 301db0f..57d40b1 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -141,6 +141,8 @@ static uint32_t calc_nr_buckets(unsigned nr_cells)
 	return n;
 }
 
+struct kmem_cache *_cell_cache;
+
 /*
  * @nr_cells should be the number of cells you want in use _concurrently_.
  * Don't confuse it with the number of distinct keys.
@@ -157,8 +159,7 @@ static struct bio_prison *prison_create(unsigned nr_cells)
 		return NULL;
 
 	spin_lock_init(&prison->lock);
-	prison->cell_pool = mempool_create_kmalloc_pool(nr_cells,
-							sizeof(struct cell));
+	prison->cell_pool = mempool_create_slab_pool(nr_cells, _cell_cache);
 	if (!prison->cell_pool) {
 		kfree(prison);
 		return NULL;
@@ -1649,6 +1650,9 @@ static void pool_features_init(struct pool_features *pf)
 	pf->discard_passdown = 1;
 }
 
+struct kmem_cache *_new_mapping_cache;
+struct kmem_cache *_endio_hook_cache;
+
 static void __pool_destroy(struct pool *pool)
 {
 	__pool_table_remove(pool);
@@ -1738,7 +1742,7 @@ static struct pool *pool_create(struct mapped_device *pool_md,
 
 	pool->next_mapping = NULL;
 	pool->mapping_pool =
-		mempool_create_kmalloc_pool(MAPPING_POOL_SIZE, sizeof(struct new_mapping));
+		mempool_create_slab_pool(MAPPING_POOL_SIZE, _new_mapping_cache);
 	if (!pool->mapping_pool) {
 		*error = "Error creating pool's mapping mempool";
 		err_p = ERR_PTR(-ENOMEM);
@@ -1746,7 +1750,7 @@ static struct pool *pool_create(struct mapped_device *pool_md,
 	}
 
 	pool->endio_hook_pool =
-		mempool_create_kmalloc_pool(ENDIO_HOOK_POOL_SIZE, sizeof(struct endio_hook));
+		mempool_create_slab_pool(ENDIO_HOOK_POOL_SIZE, _endio_hook_cache);
 	if (!pool->endio_hook_pool) {
 		*error = "Error creating pool's endio_hook mempool";
 		err_p = ERR_PTR(-ENOMEM);
@@ -2748,7 +2752,42 @@ static int __init dm_thin_init(void)
 
 	r = dm_register_target(&pool_target);
 	if (r)
-		dm_unregister_target(&thin_target);
+		goto bad_pool_target;
+
+	_cell_cache = kmem_cache_create("dm_bio_prison_cell",
+					sizeof(struct cell),
+					__alignof__(struct cell), 0, NULL);
+	if (!_cell_cache) {
+		r = -ENOMEM;
+		goto bad_cell_cache;
+	}
+
+	_new_mapping_cache = kmem_cache_create("dm_thin_new_mapping",
+					       sizeof(struct new_mapping),
+					       __alignof__(struct new_mapping), 0, NULL);
+	if (!_new_mapping_cache) {
+		r = -ENOMEM;
+		goto bad_new_mapping_cache;
+	}
+
+	_endio_hook_cache = kmem_cache_create("dm_thin_endio_hook",
+					      sizeof(struct endio_hook),
+					      __alignof__(struct endio_hook), 0, NULL);
+	if (!_endio_hook_cache) {
+		r = -ENOMEM;
+		goto bad_endio_hook_cache;
+	}
+
+	return 0;
+
+bad_endio_hook_cache:
+	kmem_cache_destroy(_new_mapping_cache);
+bad_new_mapping_cache:
+	kmem_cache_destroy(_cell_cache);
+bad_cell_cache:
+	dm_unregister_target(&pool_target);
+bad_pool_target:
+	dm_unregister_target(&thin_target);
 
 	return r;
 }
@@ -2757,6 +2796,9 @@ static void dm_thin_exit(void)
 {
 	dm_unregister_target(&thin_target);
 	dm_unregister_target(&pool_target);
+	kmem_cache_destroy(_cell_cache);
+	kmem_cache_destroy(_new_mapping_cache);
+	kmem_cache_destroy(_endio_hook_cache);
 }
 
 module_init(dm_thin_init);
-- 
1.7.4.4

^ permalink raw reply related	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell
  2012-04-12 22:34 [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell Mike Snitzer
  2012-04-12 22:34 ` [PATCH 2/2] dm thin: use slab_pool for caches Mike Snitzer
@ 2012-04-23  7:24 ` Joe Thornber
  2012-04-23 10:02   ` Alasdair G Kergon
  1 sibling, 1 reply; 6+ messages in thread
From: Joe Thornber @ 2012-04-23  7:24 UTC (permalink / raw)
  To: Mike Snitzer; +Cc: dm-devel, ejt

On Thu, Apr 12, 2012 at 06:34:34PM -0400, Mike Snitzer wrote:
> Add missing mempool_free() to __cell_release_singleton().
> 
> This is a pretty significant leak that will accumulate to over 2GB of
> leaked memory just from running the full thinp-test-suite.

When was this introduced?  With agk's tweaks for 3.4?

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell
  2012-04-23 10:02   ` Alasdair G Kergon
@ 2012-04-23  9:26     ` Joe Thornber
  0 siblings, 0 replies; 6+ messages in thread
From: Joe Thornber @ 2012-04-23  9:26 UTC (permalink / raw)
  To: ejt, dm-devel

On Mon, Apr 23, 2012 at 11:02:46AM +0100, Alasdair G Kergon wrote:
> On Mon, Apr 23, 2012 at 08:24:08AM +0100, Joe Thornber wrote:
> > On Thu, Apr 12, 2012 at 06:34:34PM -0400, Mike Snitzer wrote:
> > > Add missing mempool_free() to __cell_release_singleton().
> > > 
> > > This is a pretty significant leak that will accumulate to over 2GB of
> > > leaked memory just from running the full thinp-test-suite.
> > When was this introduced?  With agk's tweaks for 3.4?
>  
> I think it was here:
>   http://www.redhat.com/archives/dm-devel/2012-March/msg00080.html

Yep, this should call mempool_release:

@@ -305,22 +310,45 @@ static void cell_release(struct cell *cell, struct bio_list *bios)
  * bio may be in the cell.  This function releases the cell, and also does
  * a sanity check.
  */
+static void __cell_release_singleton(struct cell *cell, struct bio *bio)
+{
+	hlist_del(&cell->list);
+	BUG_ON(cell->holder != bio);
+	BUG_ON(!bio_list_empty(&cell->bios));
+}
+

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell
  2012-04-23  7:24 ` [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell Joe Thornber
@ 2012-04-23 10:02   ` Alasdair G Kergon
  2012-04-23  9:26     ` Joe Thornber
  0 siblings, 1 reply; 6+ messages in thread
From: Alasdair G Kergon @ 2012-04-23 10:02 UTC (permalink / raw)
  To: ejt; +Cc: dm-devel

On Mon, Apr 23, 2012 at 08:24:08AM +0100, Joe Thornber wrote:
> On Thu, Apr 12, 2012 at 06:34:34PM -0400, Mike Snitzer wrote:
> > Add missing mempool_free() to __cell_release_singleton().
> > 
> > This is a pretty significant leak that will accumulate to over 2GB of
> > leaked memory just from running the full thinp-test-suite.
> When was this introduced?  With agk's tweaks for 3.4?
 
I think it was here:
  http://www.redhat.com/archives/dm-devel/2012-March/msg00080.html

Localised fix:
  http://people.redhat.com/agk/patches/linux/editing/dm-thin-reinstate-missing-mempool_free-in-cell_release_singleton.patch

Alasdair

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2012-04-23 10:02 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-04-12 22:34 [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell Mike Snitzer
2012-04-12 22:34 ` [PATCH 2/2] dm thin: use slab_pool for caches Mike Snitzer
2012-04-12 22:39   ` [PATCH 2/2 v2] dm thin: use slab mempools with local caches Mike Snitzer
2012-04-23  7:24 ` [PATCH 1/2] dm thin: fix memory leak of singleton bio-prison cell Joe Thornber
2012-04-23 10:02   ` Alasdair G Kergon
2012-04-23  9:26     ` Joe Thornber

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