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>

RDMA/core: Trace points for diagnosing completion queue issues

Sample trace events:

kworker/u29:0-300 [007] 120.042217: cq_alloc: cq.id=4 nr_cqe=161 comp_vector=2 poll_ctx=WORKQUEUE
<idle>-0 [002] 120.056292: cq_schedule: cq.id=4
kworker/2:1H-482 [002] 120.056402: cq_process: cq.id=4 wake-up took 109 [us] from interrupt
kworker/2:1H-482 [002] 120.056407: cq_poll: cq.id=4 requested 16, returned 1
<idle>-0 [002] 120.067503: cq_schedule: cq.id=4
kworker/2:1H-482 [002] 120.067537: cq_process: cq.id=4 wake-up took 34 [us] from interrupt
kworker/2:1H-482 [002] 120.067541: cq_poll: cq.id=4 requested 16, returned 1
<idle>-0 [002] 120.067657: cq_schedule: cq.id=4
kworker/2:1H-482 [002] 120.067672: cq_process: cq.id=4 wake-up took 15 [us] from interrupt
kworker/2:1H-482 [002] 120.067674: cq_poll: cq.id=4 requested 16, returned 1

...

systemd-1 [002] 122.392653: cq_schedule: cq.id=4
kworker/2:1H-482 [002] 122.392688: cq_process: cq.id=4 wake-up took 35 [us] from interrupt
kworker/2:1H-482 [002] 122.392693: cq_poll: cq.id=4 requested 16, returned 16
kworker/2:1H-482 [002] 122.392836: cq_poll: cq.id=4 requested 16, returned 16
kworker/2:1H-482 [002] 122.392970: cq_poll: cq.id=4 requested 16, returned 16
kworker/2:1H-482 [002] 122.393083: cq_poll: cq.id=4 requested 16, returned 16
kworker/2:1H-482 [002] 122.393195: cq_poll: cq.id=4 requested 16, returned 3

Several features to note in this output:
- The WCE count and context type are reported at allocation time
- The CPU and kworker for each CQ is evident
- The CQ's restracker ID is tagged on each trace event
- CQ poll scheduling latency is measured
- Details about how often single completions occur versus multiple
completions are evident
- The cost of the ULP's completion handler is recorded

Link: https://lore.kernel.org/r/20191218201815.30584.3481.stgit@manet.1015granger.net
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Parav Pandit <parav@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>