Move active request tracking to a backend vfunc rather than assuming all
backends want to do this in the manner. In the of case execlists /
ring submission the tracking is on the physical engine while with GuC
submission it is on the context.
Signed-off-by: NMatthew Brost <matthew.brost@intel.com>
Reviewed-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727002348.97202-8-matthew.brost@intel.com

Hold a reference to the intel_context over life of an i915_request.
Without this an i915_request can exist after the context has been
destroyed (e.g. request retired, context closed, but user space holds a
reference to the request from an out fence). In the case of GuC
submission + virtual engine, the engine that the request references is
also destroyed which can trigger bad pointer dref in fence ops (e.g.
i915_fence_get_driver_name). We could likely change
i915_fence_get_driver_name to avoid touching the engine but let's just
be safe and hold the intel_context reference.

v2:
 (John Harrison)
  - Update comment explaining how GuC mode and execlists mode deal with
    virtual engines differently
Signed-off-by: NMatthew Brost <matthew.brost@intel.com>
Reviewed-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727002348.97202-4-matthew.brost@intel.com

The serial number tracking of engines happens at the backend of
request submission and was expecting to only be given physical
engines. However, in GuC submission mode, the decomposition of virtual
to physical engines does not happen in i915. Instead, requests are
submitted to their virtual engine mask all the way through to the
hardware (i.e. to GuC). This would mean that the heart beat code
thinks the physical engines are idle due to the serial number not
incrementing. Which in turns means hangcheck does not work for
GuC virtual engines.

This patch updates the tracking to decompose virtual engines into
their physical constituents and tracks the request against each. This
is not entirely accurate as the GuC will only be issuing the request
to one physical engine. However, it is the best that i915 can do given
that it has no knowledge of the GuC's scheduling decisions.

Downside of this is that all physical engines constituting a GuC
virtual engine will be periodically unparked (even during just a single
context executing) in order to be pinged with a heartbeat request.
However the power and performance cost of this is not expected to be
measurable (due low frequency of heartbeat pulses) and it is considered
an easier option than trying to make changes to GuC firmware.

v2:
 (Tvrtko)
  - Update commit message
  - Have default behavior if no vfunc present
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NMatthew Brost <matthew.brost@intel.com>
Reviewed-by: NMatthew Brost <matthew.brost@intel.com>
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727002348.97202-3-matthew.brost@intel.com

If two requests are on the same ring, they are explicitly ordered by the
HW. So, a submission fence is sufficient to ensure ordering when using
the new GuC submission interface. Conversely, if two requests share a
timeline and are on the same physical engine but different context this
doesn't ensure ordering on the new GuC submission interface. So, a
completion fence needs to be used to ensure ordering.

v2:
 (Daniele)
  - Don't delete spin lock
v3:
 (Daniele)
  - Delete forward dec
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NMatthew Brost <matthew.brost@intel.com>
Reviewed-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721215101.139794-13-matthew.brost@intel.com

Implement GuC context operations which includes GuC specific operations
alloc, pin, unpin, and destroy.

v2:
 (Daniel Vetter)
  - Use msleep_interruptible rather than cond_resched in busy loop
 (Michal)
  - Remove C++ style comment
v3:
 (Matthew Brost)
  - Drop GUC_ID_START
 (John Harrison)
  - Fix a bunch of typos
  - Use drm_err rather than drm_dbg for G2H errors
 (Daniele)
  - Fix ;; typo
  - Clean up sched state functions
  - Add lockdep for guc_id functions
  - Don't call __release_guc_id when guc_id is invalid
  - Use MISSING_CASE
  - Add comment in guc_context_pin
  - Use shorter path to rpm
 (Daniele / CI)
  - Don't call release_guc_id on an invalid guc_id in destroy
v4:
 (Daniel Vetter)
  - Add FIXME comment
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NMatthew Brost <matthew.brost@intel.com>
Reviewed-by: NJohn Harrison <John.C.Harrison@Intel.com>
Signed-off-by: NJohn Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721215101.139794-7-matthew.brost@intel.com

This essentially reverts

commit 84a10749
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Wed Jan 24 11:36:08 2018 +0000

    drm/i915: Shrink the GEM kmem_caches upon idling

mm/vmscan.c:do_shrink_slab() is a thing, if there's an issue with it
then we need to fix that there, not hand-roll our own slab shrinking
code in i915.

Also when this was added there was only one other caller of
kmem_cache_shrink (added 2005 to the acpi code). Now there's a 2nd one
outside of i915 code in a kunit test, which seems legit since that
wants to very carefully control what's in the kmem_cache. This out of
a total of over 500 calls to kmem_cache_create. This alone should have
been warning sign enough that we're doing something silly.

Noticed while reviewing a patch set from Jason to fix up some issues
in our i915_init() and i915_exit() module load/cleanup code. Now that
i915_globals.c isn't any different than normal init/exit functions, we
should convert them over to one unified table and remove
i915_globals.[hc] entirely.

v2: Improve commit message (Jason)
Reviewed-by: NJason Ekstrand <jason@jlekstrand.net>
Cc: David Airlie <airlied@linux.ie>
Cc: Jason Ekstrand <jason@jlekstrand.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210721183229.4136488-1-daniel.vetter@ffwll.ch

This reverts commit 9e31c1fe.  Ever
since that commit, we've been having issues where a hang in one client
can propagate to another.  In particular, a hang in an app can propagate
to the X server which causes the whole desktop to lock up.

Error propagation along fences sound like a good idea, but as your bug
shows, surprising consequences, since propagating errors across security
boundaries is not a good thing.

What we do have is track the hangs on the ctx, and report information to
userspace using RESET_STATS. That's how arb_robustness works. Also, if my
understanding is still correct, the EIO from execbuf is when your context
is banned (because not recoverable or too many hangs). And in all these
cases it's up to userspace to figure out what is all impacted and should
be reported to the application, that's not on the kernel to guess and
automatically propagate.

What's more, we're also building more features on top of ctx error
reporting with RESET_STATS ioctl: Encrypted buffers use the same, and the
userspace fence wait also relies on that mechanism. So it is the path
going forward for reporting gpu hangs and resets to userspace.

So all together that's why I think we should just bury this idea again as
not quite the direction we want to go to, hence why I think the revert is
the right option here.

For backporters: Please note that you _must_ have a backport of
https://lore.kernel.org/dri-devel/20210602164149.391653-2-jason@jlekstrand.net/
for otherwise backporting just this patch opens up a security bug.

v2: Augment commit message. Also restore Jason's sob that I
accidentally lost.

v3: Add a note for backporters
Signed-off-by: NJason Ekstrand <jason@jlekstrand.net>
Reported-by: NMarcin Slusarz <marcin.slusarz@intel.com>
Cc: <stable@vger.kernel.org> # v5.6+
Cc: Jason Ekstrand <jason.ekstrand@intel.com>
Cc: Marcin Slusarz <marcin.slusarz@intel.com>
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3080
Fixes: 9e31c1fe ("drm/i915: Propagate errors on awaiting already signaled fences")
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NJon Bloomfield <jon.bloomfield@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210714193419.1459723-3-jason@jlekstrand.net

This was only ever used for FENCE_SUBMIT automatic engine selection
which was removed in the previous commit.
Signed-off-by: NJason Ekstrand <jason@jlekstrand.net>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-12-jason@jlekstrand.net

The schedule function should be in the schedule object.

v3:
 (Jason Ekstrand)
  Add kernel doc
Signed-off-by: NMatthew Brost <matthew.brost@intel.com>
Reviewed-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210618010638.98941-6-matthew.brost@intel.com

Move active request tracking and its lock to i915_sched_engine. This
lock is also the submission lock so having it in the i915_sched_engine
is the correct place.

v3:
 (Jason Ekstrand)
  Add kernel doc
v6:
  Rebase
Signed-off-by: NMatthew Brost <matthew.brost@intel.com>
Reviewed-by: NDaniele Ceraolo Spurio <daniele.ceraolospurio@intel.comk>
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210618010638.98941-5-matthew.brost@intel.com

This was done by the following semantic patch:

	@@ expression i915; @@
	- INTEL_GEN(i915)
	+ GRAPHICS_VER(i915)

	@@ expression i915; expression E; @@
	- INTEL_GEN(i915) >= E
	+ GRAPHICS_VER(i915) >= E

	@@ expression dev_priv; expression E; @@
	- !IS_GEN(dev_priv, E)
	+ GRAPHICS_VER(dev_priv) != E

	@@ expression dev_priv; expression E; @@
	- IS_GEN(dev_priv, E)
	+ GRAPHICS_VER(dev_priv) == E

	@@
	expression dev_priv;
	expression from, until;
	@@
	- IS_GEN_RANGE(dev_priv, from, until)
	+ IS_GRAPHICS_VER(dev_priv, from, until)

	@def@
	expression E;
	identifier id =~ "^gen$";
	@@
	- id = GRAPHICS_VER(E)
	+ ver = GRAPHICS_VER(E)

	@@
	identifier def.id;
	@@
	- id
	+ ver

It also takes care of renaming the variable we assign to GRAPHICS_VER()
so to use "ver" rather than "gen".
Signed-off-by: NLucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: NMatt Roper <matthew.d.roper@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210606045050.103862-2-lucas.demarchi@intel.com

The functions can be called both in _rcu context as well
as while holding the lock.

v2: add some kerneldoc as suggested by Daniel
v3: fix indentation
Signed-off-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NJason Ekstrand <jason@jlekstrand.net>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210602111714.212426-7-christian.koenig@amd.com

That describes much better what the function is doing here.
Signed-off-by: NChristian König <christian.koenig@amd.com>
Reviewed-by: NJason Ekstrand <jason@jlekstrand.net>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210602111714.212426-6-christian.koenig@amd.com

This maybe uses lockdep through the fs_reclaim annotations.
Signed-off-by: NBernard Zhao <bernard@vivo.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210429021327.57944-1-bernard@vivo.com

Reference needs to be taken before arming the timer. Luckily, given the
default timer period of 20s, the potential to hit the race is extremely
unlikely.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: 9b4d0598 ("drm/i915: Request watchdog infrastructure")
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210326105759.2387104-1-tvrtko.ursulin@linux.intel.com
(cherry picked from commit f7c37977)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Reference needs to be taken before arming the timer. Luckily, given the
default timer period of 20s, the potential to hit the race is extremely
unlikely.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: 9b4d0598 ("drm/i915: Request watchdog infrastructure")
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210326105759.2387104-1-tvrtko.ursulin@linux.intel.com

Prepares the plumbing for setting request/fence expiration time. All code
is put in place but is never activated due yet missing ability to actually
configure the timer.

Outline of the basic operation:

A timer is started when request is ready for execution. If the request
completes (retires) before the timer fires, timer is cancelled and nothing
further happens.

If the timer fires request is added to a lockless list and worker queued.
Purpose of this is twofold: a) It allows request cancellation from a more
friendly context and b) coalesces multiple expirations into a single event
of consuming the list.

Worker locklessly consumes the list of expired requests and cancels them
all using previous added i915_request_cancel().

Associated timeout value is stored in rq->context.watchdog.timeout_us.

v2:
 * Log expiration.

v3:
 * Include more information about user timeline in the log message.

v4:
 * Remove obsolete comment and fix formatting. (Matt)
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210324121335.2307063-6-tvrtko.ursulin@linux.intel.com

Currently, we cancel outstanding requests within a context when the
context is closed. We may also want to cancel individual requests using
the same graceful preemption mechanism.

v2 (Tvrtko):
 * Cancel waiters carefully considering no timeline lock and RCU.
 * Fixed selftests.

v3 (Tvrtko):
 * Remove error propagation to waiters for now.

v4 (Tvrtko):
 * Rebase for extracted i915_request_active_engine. (Matt)
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
[danvet: Resolve conflict because intel_engine_flush_scheduler is
still called intel_engine_flush_submission]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210324121335.2307063-3-tvrtko.ursulin@linux.intel.com

Move active engine lookup to exported i915_request_active_engine.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NMatthew Auld <matthew.auld@intel.com>
[danvet: Slight rebase, engine->sched.lock is still called
engine->active.lock.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210324121335.2307063-2-tvrtko.ursulin@linux.intel.com

As soon as we mark a request as completed, it may be retired. So when
cancelling a request and marking it complete, make sure we first keep a
reference to the request.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210201085715.27435-4-chris@chris-wilson.co.ukSigned-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Instead of sharing pages with breadcrumbs, give each timeline a
single page. This allows unrelated timelines not to share locks
any more during command submission.

As an additional benefit, seqno wraparound no longer requires
i915_vma_pin, which means we no longer need to worry about a
potential -EDEADLK at a point where we are ready to submit.

Changes since v1:
- Fix erroneous i915_vma_acquire that should be a i915_vma_release (ickle).
- Extra check for completion in intel_read_hwsp().
Changes since v2:
- Fix inconsistent indent in hwsp_alloc() (kbuild)
- memset entire cacheline to 0.
Changes since v3:
- Do same in intel_timeline_reset_seqno(), and clflush for good measure.
Changes since v4:
- Use refcounting on timeline, instead of relying on i915_active.
- Fix waiting on kernel requests.
Changes since v5:
- Bump amount of slots to maximum (256), for best wraparounds.
- Add hwsp_offset to i915_request to fix potential wraparound hang.
- Ensure timeline wrap test works with the changes.
- Assign hwsp in intel_timeline_read_hwsp() within the rcu lock to
  fix a hang.
Changes since v6:
- Rename i915_request_active_offset to i915_request_active_seqno(),
  and elaborate the function. (tvrtko)
Changes since v7:
- Move hunk to where it belongs. (jekstrand)
- Replace CACHELINE_BYTES with TIMELINE_SEQNO_BYTES. (jekstrand)
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com> #v1
Reported-by: Nkernel test robot <lkp@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210323155059.628690-2-maarten.lankhorst@linux.intel.com

Avoid the full blown memory barrier of test_and_set_bit() by noting the
completed request and removing it from the lists.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210114135612.13210-5-chris@chris-wilson.co.uk

Originally, we used the signal->lock as a means of following the
previous link in its timeline and peeking at the previous fence.
However, we have replaced the explicit serialisation with a series of
very careful probes that anticipate the links being deleted and the
fences recycled before we are able to acquire a strong reference to it.
We do not need the signal->lock crutch anymore, nor want the contention.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210114135612.13210-2-chris@chris-wilson.co.uk

When we know that we are inside the timeline mutex, or inside the
submission flow (under active.lock or the holder's rcu lock), we know
that the rq->hwsp is stable and we can use the simpler direct version.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210114135612.13210-1-chris@chris-wilson.co.uk

When wedging the device, we cancel all outstanding requests and mark
them as EIO. Rather than duplicate the small function to do so between
each submission backend, export one.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Reviewed-by: NAndi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210109163455.28466-3-chris@chris-wilson.co.uk

Since we use a flag within i915_request.flags to indicate when we have
boosted the request (so that we only apply the boost) once, this can be
used as the serialisation with i915_request_retire() to avoid having to
explicitly take the i915_request.lock which is more heavily contended.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201231093149.19086-1-chris@chris-wilson.co.uk

We only need to evaluate the current status of the context when it is
scheduled in, we will force a reschedule when the context is closed
propagating the change to inflight contexts.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201231093946.11649-1-chris@chris-wilson.co.uk

Since we process schedule-in of a context after submitting the request,
if we decide to reset the context at that time, we also have to cancel
the requets we have marked for submission.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201230220028.17089-1-chris@chris-wilson.co.uk

Rather than having special case code for opportunistically calling
process_csb() and performing a direct submit while holding the engine
spinlock for submitting the request, simply call the tasklet directly.
This allows us to retain the direct submission path, including the CS
draining to allow fast/immediate submissions, without requiring any
duplicated code paths, and most importantly greatly simplifying the
control flow by removing reentrancy. This will enable us to close a few
races in the virtual engines in the next few patches.

The trickiest part here is to ensure that paired operations (such as
schedule_in/schedule_out) remain under consistent locking domains,
e.g. when pulled outside of the engine->active.lock

v2: Use bh kicking, see commit 3c53776e ("Mark HI and TASKLET
softirq synchronous").
v3: Update engine-reset to be tasklet aware
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201224135544.1713-1-chris@chris-wilson.co.uk

tasklet_kill() ensures that we _yield_ the processor until a remote
tasklet is completed. However, this leads to a starvation condition as
being at the bottom of the scheduler's runqueue means that anything else
is able to run, including all hogs keeping the tasklet occupied.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201220134858.10510-1-chris@chris-wilson.co.uk

Reduce the pollution of intel_engine.h by moving gen8_emit_pipe_control
and friends to gen8_engine_cs.h
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201216135452.6063-1-chris@chris-wilson.co.uk

Since the introduction of preempt-to-busy, requests can complete in the
background, even while they are not on the engine->active.requests list.
As such, the engine->active.request list itself is not in strict
retirement order, and we have to scan the entire list while unwinding to
not miss any. However, if the request is completed we currently leave it
on the list [until retirement], but we could just as simply remove it
and stop treating it as active. We would only have to then traverse it
once while unwinding in quick succession.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201126140407.31952-1-chris@chris-wilson.co.uk

Get rid of the __call_single_node union and clean up the API a little
to avoid external code relying on the structure layout as much.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NFrederic Weisbecker <frederic@kernel.org>

We plan to expand upon the number of available statuses for when we
pretty-print the requests along the timelines, and so need a new set of
flags. We have settled upon:

	Unready [U]
	  - initial status after being submitted, the request is not
	    ready for execution as it is waiting for external fences

	Ready [R]
	  - all fences the request was waiting on have been signaled,
            and the request is now ready for execution and will be
	    in a backend queue

	  - a ready request may still need to wait on semaphores
	    [internal fences]

	Ready/virtual [V]
	  - same as ready, but queued over multiple backends

	Executing [E]
	  - the request has been transferred from the backend queue and
	    submitted for execution on HW

	  - a completed request may still be regarded as executing, its
	    status may not be updated until it is retired and removed
	    from the lists
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201119165616.10834-3-chris@chris-wilson.co.uk

Extract i915_request_show for reuse in other request chain pretty
printers.

For a bonus point, quietly change the seqno format from %llx to %lld to
match everywhere else.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201119165616.10834-2-chris@chris-wilson.co.uk

We'll use these in the new, lockless kretprobes code.
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: NIngo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/159870619318.1229682.13027387548510028721.stgit@devnote2

We only allow persistent requests to remain on the GPU past the closure
of their containing context (and process) so long as they are continuously
checked for hangs or allow other requests to preempt them, as we need to
ensure forward progress of the system. If we allow persistent contexts
to remain on the system after the the hangcheck mechanism is disabled,
the system may grind to a halt. On disabling the mechanism, we sent a
pulse along the engine to remove all executing contexts from the engine
which would check for hung contexts -- but we did not prevent those
contexts from being resubmitted if they survived the final hangcheck.

Fixes: 9a40bddd ("drm/i915/gt: Expose heartbeat interval via sysfs")
Testcase: igt/gem_ctx_persistence/heartbeat-stop
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.7+
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200928221510.26044-1-chris@chris-wilson.co.uk
(cherry picked from commit 7a991cd3)
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

The reordering and rebasing of commit 2e4c6c1a ("drm/i915: Remove
i915_request.lock requirement for execution callbacks") caused it to
revert an earlier correction. Let us restore commit 99f0a640d464
("drm/i915: Remove requirement for holding i915_request.lock for
breadcrumbs")

Fixes: 2e4c6c1a ("drm/i915: Remove i915_request.lock requirement for execution callbacks")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200925101107.27869-1-chris@chris-wilson.co.uk
(cherry picked from commit 35faeb7d)
Signed-off-by: NRodrigo Vivi <rodrigo.vivi@intel.com>

We only allow persistent requests to remain on the GPU past the closure
of their containing context (and process) so long as they are continuously
checked for hangs or allow other requests to preempt them, as we need to
ensure forward progress of the system. If we allow persistent contexts
to remain on the system after the the hangcheck mechanism is disabled,
the system may grind to a halt. On disabling the mechanism, we sent a
pulse along the engine to remove all executing contexts from the engine
which would check for hung contexts -- but we did not prevent those
contexts from being resubmitted if they survived the final hangcheck.

Fixes: 9a40bddd ("drm/i915/gt: Expose heartbeat interval via sysfs")
Testcase: igt/gem_ctx_persistence/heartbeat-stop
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.7+
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Acked-by: NJoonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200928221510.26044-1-chris@chris-wilson.co.uk

The reordering and rebasing of commit 2e4c6c1a ("drm/i915: Remove
i915_request.lock requirement for execution callbacks") caused it to
revert an earlier correction. Let us restore commit 99f0a640d464
("drm/i915: Remove requirement for holding i915_request.lock for
breadcrumbs")

Fixes: 2e4c6c1a ("drm/i915: Remove i915_request.lock requirement for execution callbacks")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200925101107.27869-1-chris@chris-wilson.co.uk