reduce lock congestion and improve SMP scalability of the SCSI/ATA stack,
preparing the ground for the coming next GEOM direct dispatch support.
Replace big per-SIM locks with bunch of smaller ones:
- per-LUN locks to protect device and peripheral drivers state;
- per-target locks to protect list of LUNs on target;
- per-bus locks to protect reference counting;
- per-send queue locks to protect queue of CCBs to be sent;
- per-done queue locks to protect queue of completed CCBs;
- remaining per-SIM locks now protect only HBA driver internals.
While holding LUN lock it is allowed (while not recommended for performance
reasons) to take SIM lock. The opposite acquisition order is forbidden.
All the other locks are leaf locks, that can be taken anywhere, but should
not be cascaded. Many functions, such as: xpt_action(), xpt_done(),
xpt_async(), xpt_create_path(), etc. are no longer require (but allow) SIM
lock to be held.
To keep compatibility and solve cases where SIM lock can't be dropped, all
xpt_async() calls in addition to xpt_done() calls are queued to completion
threads for async processing in clean environment without SIM lock held.
Instead of single CAM SWI thread, used for commands completion processing
before, use multiple (depending on number of CPUs) threads. Load balanced
between them using "hash" of the device B:T:L address.
HBA drivers that can drop SIM lock during completion processing and have
sufficient number of completion threads to efficiently scale to multiple
CPUs can use new function xpt_done_direct() to avoid extra context switch.
Make ahci(4) driver to use this mechanism depending on hardware setup.
Sponsored by: iXsystems, Inc.
MFC after: 2 months
r248917, r248918, r248978, r249001, r249014, r249030:
Remove multilevel freezing mechanism, implemented to handle specifics of
the ATA/SATA error recovery, when post-reset recovery commands should be
allocated when queues are already full of payload requests. Instead of
removing frozen CCBs with specified range of priorities from the queue
to provide free openings, use simple hack, allowing explicit CCBs over-
allocation for requests with priority higher (numerically lower) then
CAM_PRIORITY_OOB threshold.
Simplify CCB allocation logic by removing SIM-level allocation queue.
After that SIM-level queue manages only CCBs execution, while allocation
logic is localized within each single device.
Suggested by: gibbs
and kern.cam.ctl.disable tunable; those were introduced as a workaround
to make it possible to boot GENERIC on low memory machines.
With ctl(4) being built as a module and automatically loaded by ctladm(8),
this makes CTL work out of the box.
Reviewed by: ken
Sponsored by: FreeBSD Foundation
every architecture's busdma_machdep.c. It is done by unifying the
bus_dmamap_load_buffer() routines so that they may be called from MI
code. The MD busdma is then given a chance to do any final processing
in the complete() callback.
The cam changes unify the bus_dmamap_load* handling in cam drivers.
The arm and mips implementations are updated to track virtual
addresses for sync(). Previously this was done in a type specific
way. Now it is done in a generic way by recording the list of
virtuals in the map.
Submitted by: jeff (sponsored by EMC/Isilon)
Reviewed by: kan (previous version), scottl,
mjacob (isp(4), no objections for target mode changes)
Discussed with: ian (arm changes)
Tested by: marius (sparc64), mips (jmallet), isci(4) on x86 (jharris),
amd64 (Fabian Keil <freebsd-listen@fabiankeil.de>)
Previously CTL would leave individual LUNs enabled in the target
driver, whether or not the port as a whole was enabled. It would
also leave the wildcard LUN enabled indefinitely.
This change means that CTL will enable and disable any active LUNs,
as well as the wildcard LUN, when enabling and disabling a port.
Also, fix a bug that could crop up due to an uninitialized CCB
type.
ctl.c: Before calling ctl_frontend_online(), run through
the LUN list and enable all active LUNs.
After calling ctl_frontend_offline(), run through
the LUN list and disble all active LUNs.
scsi_ctl.c: Before bringing a port online, allocate the
wildcard peripheral for that bus. And after taking
a port offline, invalidate the wildcard peripheral
for that bus.
Make sure that we hold the SIM lock around all
calls to xpt_action() and other transport layer
interfaces that require it.
Use CAM_SIM_{LOCK|UNLOCK} consistently to acquire
and release the SIM lock.
Update a number of outdated comments. Some of
these should have been fixed long ago.
Actually do LUN disbables now. The newer drivers
in the tree work correctly for this as far as I
know.
Initialize the CCB type to CTLFE_CCB_DEFAULT to
avoid a panic due to uninitialized memory.
Submitted by: Chuck Tuffli (partially)
MFC after: 1 week
ctl_frontend_cam_sim.c: Coalesce cfcs_online() and cfcs_offline()
into a single function since these were
identical except for one line.
Make sure we hold the SIM lock around path
creation, and calling xpt_rescan().
scsi_ctl.c: In ctlfe_onoffline(), make sure we hold the
SIM lock around path creation and free
calls, as well as xpt_action().
In ctlfe_lun_enable(), hold the SIM lock
around path and peripheral operations that
require it.
Sponsored by: Spectra Logic Corporation
MFC after: 1 week
data pointer. This is a temp fix that resubmits the
command, adjusted, so that the backend can fetch the
data again.
Sponsored by: Spectralogic
MFC after: 1 month
to attach to target capable HBAs that implement the old immediate
notify (XPT_IMMED_NOTIFY) and notify acknowledge (XPT_NOTIFY_ACK)
CCBs. The new API has been in place since SVN change 196008 in
2009.
The solution is two-fold: fix CTL to handle the responses from the
HBAs, and convert the HBA drivers in question to use the new API.
These drivers have not been tested with CTL, so how well they will
interoperate with CTL is unknown.
scsi_target.c: Update the userland target example code to use the
new immediate notify API.
scsi_ctl.c: Detect when an immediate notify CCB is returned
with CAM_REQ_INVALID or CAM_PROVIDE_FAIL status,
and just free it.
Fix a duplicate assignment.
aic79xx.c,
aic79xx_osm.c: Update the aic79xx driver to use the new API.
Target mode is not enabled on for this driver, so
the changes will have no practical effect.
aic7xxx.c,
aic7xxx_osm.c: Update the aic7xxx driver to use the new API.
sbp_targ.c: Update the firewire target code to work with the
new API.
mpt_cam.c: Update the mpt(4) driver to work with the new API.
Target mode is only enabled for Fibre Channel
mpt(4) devices.
MFC after: 3 days
figure out domain, etc..
Zero ATIO and INOTify allocations. It makes for much
less guesswork when looking at the structure and
seeing 'deadc0de' present.
Reviewed by: kdm
MFC after: 2 weeks
Sponsored by: Spectralogic
CTL is a disk and processor device emulation subsystem originally written
for Copan Systems under Linux starting in 2003. It has been shipping in
Copan (now SGI) products since 2005.
It was ported to FreeBSD in 2008, and thanks to an agreement between SGI
(who acquired Copan's assets in 2010) and Spectra Logic in 2010, CTL is
available under a BSD-style license. The intent behind the agreement was
that Spectra would work to get CTL into the FreeBSD tree.
Some CTL features:
- Disk and processor device emulation.
- Tagged queueing
- SCSI task attribute support (ordered, head of queue, simple tags)
- SCSI implicit command ordering support. (e.g. if a read follows a mode
select, the read will be blocked until the mode select completes.)
- Full task management support (abort, LUN reset, target reset, etc.)
- Support for multiple ports
- Support for multiple simultaneous initiators
- Support for multiple simultaneous backing stores
- Persistent reservation support
- Mode sense/select support
- Error injection support
- High Availability support (1)
- All I/O handled in-kernel, no userland context switch overhead.
(1) HA Support is just an API stub, and needs much more to be fully
functional.
ctl.c: The core of CTL. Command handlers and processing,
character driver, and HA support are here.
ctl.h: Basic function declarations and data structures.
ctl_backend.c,
ctl_backend.h: The basic CTL backend API.
ctl_backend_block.c,
ctl_backend_block.h: The block and file backend. This allows for using
a disk or a file as the backing store for a LUN.
Multiple threads are started to do I/O to the
backing device, primarily because the VFS API
requires that to get any concurrency.
ctl_backend_ramdisk.c: A "fake" ramdisk backend. It only allocates a
small amount of memory to act as a source and sink
for reads and writes from an initiator. Therefore
it cannot be used for any real data, but it can be
used to test for throughput. It can also be used
to test initiators' support for extremely large LUNs.
ctl_cmd_table.c: This is a table with all 256 possible SCSI opcodes,
and command handler functions defined for supported
opcodes.
ctl_debug.h: Debugging support.
ctl_error.c,
ctl_error.h: CTL-specific wrappers around the CAM sense building
functions.
ctl_frontend.c,
ctl_frontend.h: These files define the basic CTL frontend port API.
ctl_frontend_cam_sim.c: This is a CTL frontend port that is also a CAM SIM.
This frontend allows for using CTL without any
target-capable hardware. So any LUNs you create in
CTL are visible in CAM via this port.
ctl_frontend_internal.c,
ctl_frontend_internal.h:
This is a frontend port written for Copan to do
some system-specific tasks that required sending
commands into CTL from inside the kernel. This
isn't entirely relevant to FreeBSD in general,
but can perhaps be repurposed.
ctl_ha.h: This is a stubbed-out High Availability API. Much
more is needed for full HA support. See the
comments in the header and the description of what
is needed in the README.ctl.txt file for more
details.
ctl_io.h: This defines most of the core CTL I/O structures.
union ctl_io is conceptually very similar to CAM's
union ccb.
ctl_ioctl.h: This defines all ioctls available through the CTL
character device, and the data structures needed
for those ioctls.
ctl_mem_pool.c,
ctl_mem_pool.h: Generic memory pool implementation used by the
internal frontend.
ctl_private.h: Private data structres (e.g. CTL softc) and
function prototypes. This also includes the SCSI
vendor and product names used by CTL.
ctl_scsi_all.c,
ctl_scsi_all.h: CTL wrappers around CAM sense printing functions.
ctl_ser_table.c: Command serialization table. This defines what
happens when one type of command is followed by
another type of command.
ctl_util.c,
ctl_util.h: CTL utility functions, primarily designed to be
used from userland. See ctladm for the primary
consumer of these functions. These include CDB
building functions.
scsi_ctl.c: CAM target peripheral driver and CTL frontend port.
This is the path into CTL for commands from
target-capable hardware/SIMs.
README.ctl.txt: CTL code features, roadmap, to-do list.
usr.sbin/Makefile: Add ctladm.
ctladm/Makefile,
ctladm/ctladm.8,
ctladm/ctladm.c,
ctladm/ctladm.h,
ctladm/util.c: ctladm(8) is the CTL management utility.
It fills a role similar to camcontrol(8).
It allow configuring LUNs, issuing commands,
injecting errors and various other control
functions.
usr.bin/Makefile: Add ctlstat.
ctlstat/Makefile
ctlstat/ctlstat.8,
ctlstat/ctlstat.c: ctlstat(8) fills a role similar to iostat(8).
It reports I/O statistics for CTL.
sys/conf/files: Add CTL files.
sys/conf/NOTES: Add device ctl.
sys/cam/scsi_all.h: To conform to more recent specs, the inquiry CDB
length field is now 2 bytes long.
Add several mode page definitions for CTL.
sys/cam/scsi_all.c: Handle the new 2 byte inquiry length.
sys/dev/ciss/ciss.c,
sys/dev/ata/atapi-cam.c,
sys/cam/scsi/scsi_targ_bh.c,
scsi_target/scsi_cmds.c,
mlxcontrol/interface.c: Update for 2 byte inquiry length field.
scsi_da.h: Add versions of the format and rigid disk pages
that are in a more reasonable format for CTL.
amd64/conf/GENERIC,
i386/conf/GENERIC,
ia64/conf/GENERIC,
sparc64/conf/GENERIC: Add device ctl.
i386/conf/PAE: The CTL frontend SIM at least does not compile
cleanly on PAE.
Sponsored by: Copan Systems, SGI and Spectra Logic
MFC after: 1 month
