7364 NVMe driver performance can be improved by caching nvme_dma_t structs for PRPL.
Reviewed by: Hans Rosenfeld <hans.rosenfeld@nexenta.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Garrett D'Amore <garrett@lucera.com>

*** 9,18 ****
--- 9,19 ----
   * http://www.illumos.org/license/CDDL.
   */
  
  /*
   * Copyright 2016 Nexenta Systems, Inc. All rights reserved.
+  * Copyright 2016 The MathWorks, Inc. All rights reserved.
   */
  
  #ifndef _NVME_VAR_H
  #define _NVME_VAR_H
  
*** 55,64 ****
--- 56,66 ----
          ddi_acc_handle_t nd_acch;
          ddi_dma_cookie_t nd_cookie;
          uint_t nd_ncookie;
          caddr_t nd_memp;
          size_t nd_len;
+         boolean_t nd_cached;
  };
  
  struct nvme_cmd {
          nvme_sqe_t nc_sqe;
          nvme_cqe_t nc_cqe;
*** 106,115 ****
--- 108,118 ----
  
          caddr_t n_regs;
          ddi_acc_handle_t n_regh;
  
          kmem_cache_t *n_cmd_cache;
+         kmem_cache_t *n_prp_cache;
  
          size_t n_inth_sz;
          ddi_intr_handle_t *n_inth;
          int n_intr_cnt;
          uint_t n_intr_pri;