[patch resend 1/3] block: allocate request memory local to request queue

[patch resend 1/3] block: allocate request memory local to request queue

[David Rientjes]

blk_init_rl() allocates a mempool using mempool_create_node() with node
local memory.  This only allocates the mempool and element list locally
to the requeue queue node.

What we really want to do is allocate the request itself local to the
queue.  To do this, we need our own alloc and free functions that will
allocate from request_cachep and pass the request queue node in to prefer
node local memory.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: David Rientjes <rientjes@google.com>
---
 block/blk-core.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -557,6 +557,18 @@ void blk_cleanup_queue(struct request_queue *q)
 }
 EXPORT_SYMBOL(blk_cleanup_queue);
 
+/* Allocate memory local to the request queue */
+static void *alloc_request_struct(gfp_t gfp_mask, void *data)
+{
+	int nid = (int)(long)data;
+	return kmem_cache_alloc_node(request_cachep, gfp_mask, nid);
+}
+
+static void free_request_struct(void *element, void *unused)
+{
+	kmem_cache_free(request_cachep, element);
+}
+
 int blk_init_rl(struct request_list *rl, struct request_queue *q,
 		gfp_t gfp_mask)
 {
@@ -569,9 +581,10 @@ int blk_init_rl(struct request_list *rl, struct request_queue *q,
 	init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
 	init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);
 
-	rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
-					  mempool_free_slab, request_cachep,
-					  gfp_mask, q->node);
+	rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, alloc_request_struct,
+					  free_request_struct,
+					  (void *)(long)q->node, gfp_mask,
+					  q->node);
 	if (!rl->rq_pool)
 		return -ENOMEM;
 

[patch resend 2/3] block, drbd: fix drbd_req_new() initialization

[David Rientjes]

mempool_alloc() does not support __GFP_ZERO since elements may come from
memory that has already been released by mempool_free().

Remove __GFP_ZERO from mempool_alloc() in drbd_req_new() and properly
initialize it to 0.

Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: David Rientjes <rientjes@google.com>
---
 drivers/block/drbd/drbd_req.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_req.c b/drivers/block/drbd/drbd_req.c
--- a/drivers/block/drbd/drbd_req.c
+++ b/drivers/block/drbd/drbd_req.c
@@ -52,9 +52,10 @@ static struct drbd_request *drbd_req_new(struct drbd_device *device,
 {
 	struct drbd_request *req;
 
-	req = mempool_alloc(drbd_request_mempool, GFP_NOIO | __GFP_ZERO);
+	req = mempool_alloc(drbd_request_mempool, GFP_NOIO);
 	if (!req)
 		return NULL;
+	memset(req, 0, sizeof(*req));
 
 	drbd_req_make_private_bio(req, bio_src);
 	req->rq_state    = bio_data_dir(bio_src) == WRITE ? RQ_WRITE : 0;

[patch resend 3/3] block, drbd: use mempool_create_slab_pool()

[David Rientjes]

Mempools created for slab caches should use
mempool_create_slab_pool().

Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: David Rientjes <rientjes@google.com>
---
 drivers/block/drbd/drbd_main.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2107,13 +2107,12 @@ static int drbd_create_mempools(void)
 	if (drbd_md_io_page_pool == NULL)
 		goto Enomem;
 
-	drbd_request_mempool = mempool_create(number,
-		mempool_alloc_slab, mempool_free_slab, drbd_request_cache);
+	drbd_request_mempool = mempool_create_slab_pool(number,
+		drbd_request_cache);
 	if (drbd_request_mempool == NULL)
 		goto Enomem;
 
-	drbd_ee_mempool = mempool_create(number,
-		mempool_alloc_slab, mempool_free_slab, drbd_ee_cache);
+	drbd_ee_mempool = mempool_create_slab_pool(number, drbd_ee_cache);
 	if (drbd_ee_mempool == NULL)
 		goto Enomem;
 

Re: [patch resend 1/3] block: allocate request memory local to request queue

[Jens Axboe]

On 03/24/2015 05:21 PM, David Rientjes wrote:
> blk_init_rl() allocates a mempool using mempool_create_node() with node
> local memory.  This only allocates the mempool and element list locally
> to the requeue queue node.
>
> What we really want to do is allocate the request itself local to the
> queue.  To do this, we need our own alloc and free functions that will
> allocate from request_cachep and pass the request queue node in to prefer
> node local memory.

Applied to for-4.1/core, thanks.

-- 
Jens Axboe

Re: [patch resend 2/3] block, drbd: fix drbd_req_new() initialization

[Jens Axboe]

On 03/24/2015 05:22 PM, David Rientjes wrote:
> mempool_alloc() does not support __GFP_ZERO since elements may come from
> memory that has already been released by mempool_free().
>
> Remove __GFP_ZERO from mempool_alloc() in drbd_req_new() and properly
> initialize it to 0.

This (and the other drbd patch) queued up in for-4.1/drivers, thanks.

-- 
Jens Axboe