Hi Martin, This cover letter describes the feature: add support for multiqueue (MQ) to fnic driver. Background: The Virtual Interface Card (VIC) firmware exposes several queues that can be configured for sending IOs and receiving IO responses. Unified Computing System Manager (UCSM) and Intersight Manager (IMM) allows users to configure the number of queues to be used for IOs. The number of IO queues to be used is stored in a configuration file by the VIC firmware. The fNIC driver reads the configuration file and sets the number of queues to be used. Previously, the driver was hard-coded to use only one queue. With this set of changes, the fNIC driver will configure itself to use multiple queues. This feature takes advantage of the block multiqueue layer to parallelize IOs being sent out of the VIC card. Here's a brief description of some of the salient patches: - vnic_scsi.h needs to be in sync with VIC firmware to be able to read the number of queues from the firmware config file. A patch has been created for this. - In an environment with many fnics (like we see in our customer environments), it is hard to distinguish which fnic is printing logs. Therefore, an fnic number has been included in the logs. - read the number of queues from the firmware config file. - include definitions in fnic.h to support multiqueue. - modify the interrupt service routines (ISRs) to read from the correct registers. The numbers that are used here come from discussions with the VIC firmware team. - track IO statistics for different queues. - remove usage of host_lock, and only use fnic_lock in the fnic driver. - use a hardware queue based spinlock to protect io_req. - replace the hard-coded zeroth queue with a hardware queue number. This presents a bulk of the changes. - modify the definition of fnic_queuecommand to accept multiqueue tags. - improve log messages, and indicate fnic number and multiqueue tags for effective debugging. Even though the patches have been made into a series, some patches are heavier than others. But, every effort has been made to keep the purpose of each patch as a single-purpose, and to compile cleanly. This patchset has been tested as a whole. Therefore, the tested-by fields have been added only to the last two patches in the set. All the individual patches compile cleanly. However, I've refrained from adding tested-by to most of the patches, so as to not mislead the reviewer/reader. A brief note on the unit tests: 1. Increase number of queues to 64. Load driver. Run IOs via Medusa. 12+ hour run successful. 2. Configure multipathing, and run link flaps on single link. IOs drop briefly, but pick up as expected. 3. Configure multipathing, and run link flaps on two links, with a 30 second delay in between. IOs drop briefly, but pick up as expected. Repeat the above tests with single queue. All tests were successful. Please consider this patch series for the next merge window. Thanks and regards, Karan Karan Tilak Kumar (13): scsi: fnic: Modify definitions to sync with VIC firmware scsi: fnic: Add and use fnic number scsi: fnic: Add and improve log messages scsi: fnic: Rename wq_copy to hw_copy_wq scsi: fnic: Get copy workqueue count and interrupt mode from config scsi: fnic: Refactor and redefine fnic.h for multiqueue scsi: fnic: Modify ISRs to support multiqueue(MQ) scsi: fnic: Define stats to track multiqueue (MQ) IOs scsi: fnic: Remove usage of host_lock scsi: fnic: Add support for multiqueue (MQ) in fnic_main.c scsi: fnic: Use fnic_lock to protect fnic structures in queuecommand scsi: fnic: Add support for multiqueue (MQ) in fnic driver scsi: fnic: Improve logs and add support for multiqueue (MQ) drivers/scsi/fnic/fnic.h | 41 +- drivers/scsi/fnic/fnic_debugfs.c | 2 +- drivers/scsi/fnic/fnic_fcs.c | 36 +- drivers/scsi/fnic/fnic_io.h | 2 + drivers/scsi/fnic/fnic_isr.c | 166 +++++-- drivers/scsi/fnic/fnic_main.c | 156 ++++-- drivers/scsi/fnic/fnic_res.c | 48 +- drivers/scsi/fnic/fnic_scsi.c | 797 ++++++++++++++++++------------- drivers/scsi/fnic/fnic_stats.h | 3 + drivers/scsi/fnic/fnic_trace.c | 11 + drivers/scsi/fnic/vnic_dev.c | 4 + drivers/scsi/fnic/vnic_scsi.h | 13 +- 12 files changed, 835 insertions(+), 444 deletions(-) -- 2.31.1
