[dm-devel] [PATCH 0/2] multipath-tools/libmultipath: Support for the native NVMe Ioctl command and add args min_avg_latency for path_latency.

[Yang Feng]

1. The SCSI-to-NVMe translations have been removed in the patch "nvme:
Remove SCSI translations" in the linux-nvme, so the native NVMe Ioctl
command should be supported in the multipath-tools.
   In the prioritizers/path_latency.c, modify the func do_readsector0():
send a native NVMe Read Ioctl command to the nvme device, and send a SG
Read Ioctl command to the scsi device.
   In the tur checker, add support for the native NVMe Keep Alive Ioctl
command to the nvme device.
2. Add args min_avg_latency of logarithmic scale, for prioritizers/
path_latency.c. Min average latency is not constant 1us, and can be set
by user. Certainly, max average latency value is still constant 100s.
It make support better for more scenes, because it can deal better with
the normal standard deviation of path latency.
   For example, when the standard deviation value is 200us and the average
latency of the normal paths is 1ms, args base_num can be set to 5 and args
min_avg_latency can be set to 2ms, so the paths will be grouped in priority
groups with path latency <=2ms, (2ms, 10ms], (10ms, 50ms], etc.

Changes from v1:
* Fix according to Xose's reviews, don't rename the tur checker.

Yang Feng (1):
   multipath-tools/libmultipath: Support for the native NVMe Ioctl command
and add args min_avg_latency for path_latency.

 libmultipath/checkers.c                  |   7 ++
 libmultipath/checkers.h                  |   4 +
 libmultipath/checkers/Makefile           |   4 +-
 libmultipath/checkers/emc_clariion.c     |   4 +-
 libmultipath/checkers/libsg.c            |  94 ----------------------
 libmultipath/checkers/libsg.h            |   9 ---
 libmultipath/checkers/readsector0.c      |   4 +-
 libmultipath/checkers/tur.c              |  64 ++++++++++-----
 libmultipath/discovery.c                 |   1 +
 libmultipath/libnvme.c                   | 130 +++++++++++++++++++++++++++++++
 libmultipath/libnvme.h                   |  10 +++
 libmultipath/libsg.c                     | 113 +++++++++++++++++++++++++++
 libmultipath/libsg.h                     |  13 ++++
 libmultipath/prioritizers/Makefile       |   2 +-
 libmultipath/prioritizers/path_latency.c |  95 ++++++++++++++--------
 multipath/multipath.conf.5               |  16 ++--
 16 files changed, 406 insertions(+), 164 deletions(-)
 delete mode 100644 libmultipath/checkers/libsg.c
 delete mode 100644 libmultipath/checkers/libsg.h
 create mode 100644 libmultipath/libnvme.c
 create mode 100644 libmultipath/libnvme.h
 create mode 100644 libmultipath/libsg.c
 create mode 100644 libmultipath/libsg.h

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2.6.4.windows.1