RDMA/core: Add trace points to follow MR allocation

Track the lifetime of ib_mr objects. Here's sample output from a test run
with NFS/RDMA:

           <...>-361   [009] 79238.772782: mr_alloc:             pd.id=3 mr.id=11 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79238.772812: mr_alloc:             pd.id=3 mr.id=12 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79238.772839: mr_alloc:             pd.id=3 mr.id=13 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79238.772866: mr_alloc:             pd.id=3 mr.id=14 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79238.772893: mr_alloc:             pd.id=3 mr.id=15 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79238.772921: mr_alloc:             pd.id=3 mr.id=16 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79238.772947: mr_alloc:             pd.id=3 mr.id=17 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79238.772974: mr_alloc:             pd.id=3 mr.id=18 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79238.773001: mr_alloc:             pd.id=3 mr.id=19 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79238.773028: mr_alloc:             pd.id=3 mr.id=20 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79238.773055: mr_alloc:             pd.id=3 mr.id=21 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.270942: mr_alloc:             pd.id=3 mr.id=22 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.270975: mr_alloc:             pd.id=3 mr.id=23 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.271007: mr_alloc:             pd.id=3 mr.id=24 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.271036: mr_alloc:             pd.id=3 mr.id=25 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.271067: mr_alloc:             pd.id=3 mr.id=26 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.271095: mr_alloc:             pd.id=3 mr.id=27 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.271121: mr_alloc:             pd.id=3 mr.id=28 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.271153: mr_alloc:             pd.id=3 mr.id=29 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.271181: mr_alloc:             pd.id=3 mr.id=30 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.271208: mr_alloc:             pd.id=3 mr.id=31 type=MEM_REG max_num_sg=30 rc=0
           <...>-361   [009] 79240.271236: mr_alloc:             pd.id=3 mr.id=32 type=MEM_REG max_num_sg=30 rc=0
           <...>-4351  [001] 79242.299400: mr_dereg:             mr.id=32
           <...>-4351  [001] 79242.299467: mr_dereg:             mr.id=31
           <...>-4351  [001] 79242.299554: mr_dereg:             mr.id=30
           <...>-4351  [001] 79242.299615: mr_dereg:             mr.id=29
           <...>-4351  [001] 79242.299684: mr_dereg:             mr.id=28
           <...>-4351  [001] 79242.299748: mr_dereg:             mr.id=27
           <...>-4351  [001] 79242.299812: mr_dereg:             mr.id=26
           <...>-4351  [001] 79242.299874: mr_dereg:             mr.id=25
           <...>-4351  [001] 79242.299944: mr_dereg:             mr.id=24
           <...>-4351  [001] 79242.300009: mr_dereg:             mr.id=23
           <...>-4351  [001] 79242.300190: mr_dereg:             mr.id=22
           <...>-4351  [001] 79242.300263: mr_dereg:             mr.id=21
           <...>-4351  [001] 79242.300326: mr_dereg:             mr.id=20
           <...>-4351  [001] 79242.300388: mr_dereg:             mr.id=19
           <...>-4351  [001] 79242.300450: mr_dereg:             mr.id=18
           <...>-4351  [001] 79242.300516: mr_dereg:             mr.id=17
           <...>-4351  [001] 79242.300629: mr_dereg:             mr.id=16
           <...>-4351  [001] 79242.300718: mr_dereg:             mr.id=15
           <...>-4351  [001] 79242.300784: mr_dereg:             mr.id=14
           <...>-4351  [001] 79242.300879: mr_dereg:             mr.id=13
           <...>-4351  [001] 79242.300945: mr_dereg:             mr.id=12
           <...>-4351  [001] 79242.301012: mr_dereg:             mr.id=11

Some features of the output:
- The lifetime and owner PD of each MR is clearly visible.
- The type of MR is captured, as is the SGE array size.
- Failing MR allocation can be recorded.

Link: https://lore.kernel.org/r/20191218201820.30584.34636.stgit@manet.1015granger.net


Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>