IB/hfi1: Improve local kmem_cache_alloc performance

Performance analysis shows that the cache callback function
sdma_kmem_cache_ctor contributes to 1/2 of the kmem_cache_allocs
time.

Since all of the fields in the allocated data structure are initialized
in the code path, remove the _ctor function.

Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/hfi1/user_sdma.c

@@ -331,13 +331,6 @@ static void activate_packet_queue(struct iowait *wait, int reason)
 	wake_up(&wait->wait_dma);
 };
 
-static void sdma_kmem_cache_ctor(void *obj)
-{
-	struct user_sdma_txreq *tx = obj;
-
-	memset(tx, 0, sizeof(*tx));
-}
-
 int hfi1_user_sdma_alloc_queues(struct hfi1_ctxtdata *uctxt,
 				struct hfi1_filedata *fd)
 {
@@ -391,7 +384,7 @@ int hfi1_user_sdma_alloc_queues(struct hfi1_ctxtdata *uctxt,
 					    sizeof(struct user_sdma_txreq),
 					    L1_CACHE_BYTES,
 					    SLAB_HWCACHE_ALIGN,
-					    sdma_kmem_cache_ctor);
+					    NULL);
 	if (!pq->txreq_cache) {
 		dd_dev_err(dd, "[%u] Failed to allocate TxReq cache\n",
 			   uctxt->ctxt);

drivers/infiniband/hw/hfi1/verbs_txreq.c

@@ -1,5 +1,5 @@
 /*
- * Copyright(c) 2016 Intel Corporation.
+ * Copyright(c) 2016 - 2017 Intel Corporation.
  *
  * This file is provided under a dual BSD/GPLv2 license.  When using or
  * redistributing this file, you may do so under either license.
@@ -119,13 +119,6 @@ out:
 	return tx;
 }
 
-static void verbs_txreq_kmem_cache_ctor(void *obj)
-{
-	struct verbs_txreq *tx = (struct verbs_txreq *)obj;
-
-	memset(tx, 0, sizeof(*tx));
-}
-
 int verbs_txreq_init(struct hfi1_ibdev *dev)
 {
 	char buf[TXREQ_LEN];
@@ -135,7 +128,7 @@ int verbs_txreq_init(struct hfi1_ibdev *dev)
 	dev->verbs_txreq_cache = kmem_cache_create(buf,
 						   sizeof(struct verbs_txreq),
 						   0, SLAB_HWCACHE_ALIGN,
-						   verbs_txreq_kmem_cache_ctor);
+						   NULL);
 	if (!dev->verbs_txreq_cache)
 		return -ENOMEM;
 	return 0;

drivers/infiniband/hw/hfi1/vnic_sdma.c

@@ -303,22 +303,15 @@ void hfi1_vnic_sdma_init(struct hfi1_vnic_vport_info *vinfo)
 	}
 }
 
-static void hfi1_vnic_txreq_kmem_cache_ctor(void *obj)
-{
-	struct vnic_txreq *tx = (struct vnic_txreq *)obj;
-
-	memset(tx, 0, sizeof(*tx));
-}
-
 int hfi1_vnic_txreq_init(struct hfi1_devdata *dd)
 {
 	char buf[HFI1_VNIC_TXREQ_NAME_LEN];
 
 	snprintf(buf, sizeof(buf), "hfi1_%u_vnic_txreq_cache", dd->unit);
 	dd->vnic.txreq_cache = kmem_cache_create(buf,
-					  sizeof(struct vnic_txreq),
-					  0, SLAB_HWCACHE_ALIGN,
-					  hfi1_vnic_txreq_kmem_cache_ctor);
+						 sizeof(struct vnic_txreq),
+						 0, SLAB_HWCACHE_ALIGN,
+						 NULL);
 	if (!dd->vnic.txreq_cache)
 		return -ENOMEM;
 	return 0;