Make CTL core and block backend set success status before initiating last
data move for read commands. Make CAM target and iSCSI frontends detect
such condition and send command status together with data. New I/O flag
allows to skip duplicate status sending on later fe_done() call.
For Fibre Channel this change saves one of three interrupts per read command,
increasing performance from 126K to 160K IOPS. For iSCSI this change saves
one of three PDUs per read command, increasing performance from 1M to 1.2M
IOPS.
MFC after: 1 month
Sponsored by: iXsystems, Inc.
Old allocator created significant lock congestion protecting its lists
of preallocated I/Os, while UMA provides much better SMP scalability.
The downside of UMA is lack of reliable preallocation, that could guarantee
successful allocation in non-sleepable environments. But careful code
review shown, that only CAM target frontend really has that requirement.
Fix that making that frontend preallocate and statically bind CTL I/O for
every ATIO/INOT it preallocates any way. That allows to avoid allocations
in hot I/O path. Other frontends either may sleep in allocation context
or can properly handle allocation errors.
On 40-core server with 6 ZVOL-backed LUNs and 7 iSCSI client connections
this change increases peak performance from ~700K to >1M IOPS! Yay! :)
MFC after: 1 month
Sponsored by: iXsystems, Inc.
In this mode one head is in Active state, supporting all commands, while
another is in Standby state, supporting only minimal LUN discovery subset.
It is still incomplete since Standby state requires reservation support,
which is impossible to do right without having interlink between heads.
But it allows to run some basic experiments.
With command serialization used in CTL, there are no other commands to abort
when PREEMPT AND ABORT gets to run, so it is practically equal to PREEMPT.
MFC after: 1 week
For ZVOL-backed LUNs this allows to inform initiators if storage's used or
available spaces get above/below the configured thresholds.
MFC after: 2 weeks
Sponsored by: iXsystems, Inc.
This makes VMWare VAAI Thin Provisioning Stun primitive activate, pausing
the virtual machine, when backing storage (ZFS pool) is getting overflowed.
MFC after: 1 week
Sponsored by: iXsystems, Inc.
This includes support for:
- Read-Write Error Recovery mode page;
- Informational Exceptions Control mode page;
- Logical Block Provisioning mode page;
- LOG SENSE command.
No real Informational Exceptions features yet. This is only a placeholder.
Sponsored by: iXsystems, Inc.
SPC-4 r2 allows to return empty defect list if the list is not supported.
We don't reallu support defect data lists, but this suppresses some errors.
MFC after: 1 week
Make this subcommand less FC-specific, reporting target and port addresses
in more generic way. Also make it report list of connected initiators in
unified way, working for both FC and iSCSI, and potentially others.
MFC after: 1 week
Queued async events handling in CAM opened race, that may lead to duplicate
AC_PATH_REGISTERED events delivery during boot. That was not happening
before r272935 because the driver was initialized later. After that change
it started create duplicate ports in CTL.
Target mode operation does not depend on the initiator mode scan process.
This change allows the target driver to attach earlier and receive some
async events (like AC_CONTRACT) that could be lost otherwise.
MFC after: 1 week
Such LUNs will be visible to initiators, but return "not ready" status
on media access commands. If backing storage become available later,
`ctladm modify ...` or `service ctld reload` can trigger its reopen.
It allows to push out some final data from the send queue to the socket
before its close. In particular, it increases chances for logout response
to be delivered to the initiator.
