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
Stop abusing xpt_periph in random plases that really have no periph related
to CCB, for example, bus scanning. NULL value is fine in such cases and it
is correctly logged in debug messages as "noperiph". If at some point we
need some real XPT periphs (alike to pmpX now), quite likely they will be
per-bus, and not a single global instance as xpt_periph now.
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
the LUN was never freed.
ctl.c: Adjust ctl_alloc_lun() to make sure we don't clear the
CTL_LUN_MALLOCED flag.
Reported by: Sreenivasa Honnur <shonnur@chelsio.com>
Sponsored by: Spectra Logic
MFC after: 3 days
copied in from userspace. This fixes instant panic when creating CTL LUN
on sparc64. Not a security problem, since the API is root-only.
Reviewed by: ken
Sponsored by: FreeBSD Foundation
tunable by default.
This will allow GENERIC configurations to boot on small memory boxes, but
not require end users who want to use CTL to recompile their kernel. They
can simply set kern.cam.ctl.disable=0 in loader.conf.
The eventual solution to the memory usage problem is to change the way
CTL allocates memory to be more configurable, but this should fix things
for small memory situations in the mean time.
UPDATING: Explain the change in the CTL configuration, and
how users can enable CTL if they would like to use
it.
sys/conf/options: Add a new option, CTL_DISABLE, that prevents CTL
from initializing.
ctl.c: If CTL_DISABLE is turned on, don't initialize.
i386/conf/GENERIC,
amd64/conf/GENERIC: Re-enable device ctl, and add the CTL_DISABLE
option.
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
while doing a copyout. That can cause a panic, because copyout
can trigger VM faults, and we can't handle VM faults while holding
a mutex.
The solution here is to malloc a separate buffer to hold the OOA
queue entries, so that we don't risk a VM fault while filling up
the buffer and we don't have to drop the lock. The other solution
would be to wire the user's memory while filling their buffer with
copyout, but that would have been a little more complex.
Also fix a debugging parenthesis issue in ctl_abort_task() pointed
out by Chuck Tuffli.
Sponsored by: Spectra Logic Corporation
MFC after: 1 week
In particular, do not lock Giant conditionally when calling into the
filesystem module, remove the VFS_LOCK_GIANT() and related
macros. Stop handling buffers belonging to non-mpsafe filesystems.
The VFS_VERSION is bumped to indicate the interface change which does
not result in the interface signatures changes.
Conducted and reviewed by: attilio
Tested by: pho
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
