Try to flush out dirty pages into the swapcache (and from there into the
swapfile) when under memory pressure and forced to drop GEM objects from
memory. In effect, this should just allow us to discard unused pages for
memory reclaim and to start writeback earlier.

v2: Hugh Dickins warned that explicitly starting writeback from
shrink_slab was prone to deadlocks within shmemfs.

Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NRobert Beckett <robert.beckett@intel.com>
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We can share a few lines of tricky lock handling we need to use for both
shrinker routines and in the process fix the return value for count()
when reporting a deadlock.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NRobert Beckett <robert.beckett@intel.com>
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When the machine is under a lot of memory pressure and being stressed by
multiple GPU threads, we quite often report fewer than shrinker->batch
(i.e. SHRINK_BATCH) pages to be freed. This causes the shrink_control to
skip calling into i915.ko to release pages, despite the GPU holding onto
most of the physical pages in its active lists.

References: https://bugs.freedesktop.org/show_bug.cgi?id=72742Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NRobert Beckett <robert.beckett@intel.com>
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

shmemfs first checks if there is enough memory to allocate the page
and reports ENOSPC should there be insufficient, along with
the usual ENOMEM for a genuine allocation failure.

We use ENOSPC in our driver to mean that we have run out of aperture
space and so want to translate the error from shmemfs back to
our usual understanding of ENOMEM. None of the the other GEM users
appear to distinguish between ENOMEM and ENOSPC in their error handling,
hence it is easiest to do the fixup in i915.ko

Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NRobert Beckett <robert.beckett@intel.com>
Reviewed-by: NRafael Barbalho <rafael.barbalho@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

By exporting the ability to map user address and inserting PTEs
representing their backing pages into the GTT, we can exploit UMA in order
to utilize normal application data as a texture source or even as a
render target (depending upon the capabilities of the chipset). This has
a number of uses, with zero-copy downloads to the GPU and efficient
readback making the intermixed streaming of CPU and GPU operations
fairly efficient. This ability has many widespread implications from
faster rendering of client-side software rasterisers (chromium),
mitigation of stalls due to read back (firefox) and to faster pipelining
of texture data (such as pixel buffer objects in GL or data blobs in CL).

v2: Compile with CONFIG_MMU_NOTIFIER
v3: We can sleep while performing invalidate-range, which we can utilise
to drop our page references prior to the kernel manipulating the vma
(for either discard or cloning) and so protect normal users.
v4: Only run the invalidate notifier if the range intercepts the bo.
v5: Prevent userspace from attempting to GTT mmap non-page aligned buffers
v6: Recheck after reacquire mutex for lost mmu.
v7: Fix implicit padding of ioctl struct by rounding to next 64bit boundary.
v8: Fix rebasing error after forwarding porting the back port.
v9: Limit the userptr to page aligned entries. We now expect userspace
    to handle all the offset-in-page adjustments itself.
v10: Prevent vma from being copied across fork to avoid issues with cow.
v11: Drop vma behaviour changes -- locking is nigh on impossible.
     Use a worker to load user pages to avoid lock inversions.
v12: Use get_task_mm()/mmput() for correct refcounting of mm.
v13: Use a worker to release the mmu_notifier to avoid lock inversion
v14: Decouple mmu_notifier from struct_mutex using a custom mmu_notifer
     with its own locking and tree of objects for each mm/mmu_notifier.
v15: Prevent overlapping userptr objects, and invalidate all objects
     within the mmu_notifier range
v16: Fix a typo for iterating over multiple objects in the range and
     rearrange error path to destroy the mmu_notifier locklessly.
     Also close a race between invalidate_range and the get_pages_worker.
v17: Close a race between get_pages_worker/invalidate_range and fresh
     allocations of the same userptr range - and notice that
     struct_mutex was presumed to be held when during creation it wasn't.
v18: Sigh. Fix the refactor of st_set_pages() to allocate enough memory
     for the struct sg_table and to clear it before reporting an error.
v19: Always error out on read-only userptr requests as we don't have the
     hardware infrastructure to support them at the moment.
v20: Refuse to implement read-only support until we have the required
     infrastructure - but reserve the bit in flags for future use.
v21: use_mm() is not required for get_user_pages(). It is only meant to
     be used to fix up the kernel thread's current->mm for use with
     copy_user().
v22: Use sg_alloc_table_from_pages for that chunky feeling
v23: Export a function for sanity checking dma-buf rather than encode
     userptr details elsewhere, and clean up comments based on
     suggestions by Bradley.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: "Gong, Zhipeng" <zhipeng.gong@intel.com>
Cc: Akash Goel <akash.goel@intel.com>
Cc: "Volkin, Bradley D" <bradley.d.volkin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Reviewed-by: NBrad Volkin <bradley.d.volkin@intel.com>
[danvet: Frob ioctl allocation to pick the next one - will cause a bit
of fuss with create2 apparently, but such are the rules.]
[danvet2: oops, forgot to git add after manual patch application]
[danvet3: Appease sparse.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Otherwise, we do a NULL pointer dereference.

I've seen this happen while handling an error in
i915_gem_object_pin_to_display_plane():

If i915_gem_object_set_cache_level() fails, we call is_pin_display()
to handle the error. At this point, the object is still not pinned
to GGTT and maybe not even bound, so we have to check before we
dereference its GGTT vma.

The IGT kms_flip/bo-too-big tests for this bug.

v2: Chris Wilson says restoring the old value is easier, but that
is_pin_display is useful as a theory of operation. Take the solomonic
decision: at least this way is_pin_display is a little more robust
(until Chris can kill it off).

v3: Chris suggests the WARN in i915_gem_obj_to_ggtt has outlived its
usefulness: add a reminder to remove it.

Issue: VIZ-3772
Signed-off-by: NOscar Mateo <oscar.mateo@intel.com>
Testcase: igt/kms_flip/bo-too-big
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Otherwise we end up tearing down fences when e.g. the client quits
way too early. Might or might not fix a fence pin_count BUG Ville has
reported.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Userspace can currently provoke this when e.g. trying to use a pinned
scanout as a cursor or overlay target. Later on that might lead to
some fun fence pin count mayhem.

Spurred by Ville's report that something goes wrong here and
originally I've thought that this might slip through the pwrite gtt
fastpath. But that one checks of obj tiling, so should be ok.

But one thing that _does_ blow up is the vma unbinding with more than
one address space. The next patch will fix this.

v2: Use a WARN_ON - Chris pointed out that we already catch all cases
so userspace can't provoke this like I've originally feared.

While reviewing relevant code I've noticed a pile of DRM_ERROR in the
overlay&cursor code which are all triggerable by userspace. Tune them
down while at it.

v3: Split out the DRM_ERROR->DRM_DEBUG_KMS change into a separate patch,
as requested by Chris.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Tested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The fence pin count should always be <= the bo pin count. If that's
not the case then we have a funny problem and are leaking references
somewhere.

Which means we can catch fence pin leaks by checking for the same
upper limit as we do for the bo pin count. Inspired by a discussion
with Ville about a fence leak igt testcase.

v2: Also check for fence->pin_count <= ggtt_vma->pin_count, since that
might catch a leak even quicker. Also de-inline them, they're getting
too big.

v3: Don't separately check for MAX_PIN_COUNT since the > vma->pin_count
check will catch that already (Chris).

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

During the review of

commit 1f70999f
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Jan 27 22:43:07 2014 +0000

    drm/i915: Prevent recursion by retiring requests when the ring is full

Ville raised the point that our interaction with request->tail was
likely to foul up other uses elsewhere (such as hang check comparing
ACTHD against requests).

However, we also need to restore the implicit retire requests that certain
test cases depend upon (e.g. igt/gem_exec_lut_handle), this raises the
spectre that the ppgtt will randomly call i915_gpu_idle() and recurse
back into intel_ring_begin().
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=78023Reviewed-by: NBrad Volkin <bradley.d.volkin@intel.com>
[danvet: Remove now unused 'tail' variable as spotted by Brad.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

There is a good debate to be had about how best to fit the aliasing
PPGTT into the code. However, as it stands right now, getting aliasing
PPGTT bindings is a hack, and done through implicit arguments. To make
this absolutely clear, WARN and return an error if a driver writer tries
to do something they shouldn't.

I have no issue with an eventual revert of this patch. It makes sense
for what we have today.
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This will be helpful in abstracting some of the code in preparation for
gen8 semaphores.

v2: Move mbox stuff to a separate struct

v3: Rebased over VCS2 work

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> (v1)
Signed-off-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

A common issue we have is that retiring requests causes recursion
through GTT manipulation or page table manipulation which we can only
handle at very specific points. However, to maintain internal
consistency (enforced through our sanity checks on write_domain at
various points in the GEM object lifecycle) we do need to retire the
object prior to marking it with a new write_domain, and also clear the
write_domain for the implicit flush following a batch.

Note that this then allows the unbound objects to still be on the active
lists, and so care must be taken when removing objects from unbound lists
(similar to the caveats we face processing the bound lists).

v2: Fix i915_gem_shrink_all() to handle updated object lifetime rules,
by refactoring it to call into __i915_gem_shrink().

v3: Missed an object-retire prior to changing cache domains in
i915_gem_object_set_cache_leve()

v4: Rebase
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Tested-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NBrad Volkin <bradley.d.volkin@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

These will be needed by the upcoming VLV RPM helpers.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: NRodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Based on the hardware spec, the BDW GT3 machine has two independent
BSD ring that can be used to dispatch the video commands.
So just initialize it.

V3->V4: Follow Imre's comment to do some minor updates. For example:
more comments are added to describe the semaphore between ring.
Reviewed-by: NImre Deak <imre.deak@intel.com>
Signed-off-by: NZhao Yakui <yakui.zhao@intel.com>
[danvet: Fix up checkpatch error.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Even without enabling the ringbuffers to allow command execution, we can
still control the display engines to enable modesetting. So make the
ringbuffer initialization failure soft, and mark the GPU as wedged
instead.

v2: Only treat an EIO from ring initialisation as a soft failure, and
abort module load for any other failure, such as allocation failures.

v3: Add an *ERROR* prior to declaring the GPU wedged so that it stands
out like a sore thumb in the logs
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: NOscar Mateo <oscar.mateo@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Tearing down the ring buffers across resume is overkill, risks
unnecessary failure and increases fragmentation.

After failure, since the device is still active we may end up trying to
write into the dangling iomapping and trigger an oops.

v2: stop_ringbuffers() was meant to call stop(ring) not
cleanup(ring) during resume!
Reported-by: NJae-hyeon Park <jhyeon@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=72351
References: https://bugs.freedesktop.org/show_bug.cgi?id=76554Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NOscar Mateo <oscar.mateo@intel.com>
[danvet: s/ring->obj == NULL/!intel_ring_initialized(ring)/ as
suggested by Oscar.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Unfortunately this requires a drm-wide change, and I didn't see a sane
way around that. Luckily it's fairly simple, we just need to inline
the respective get_irq implementation from either drm_pci.c or
drm_platform.c.

With that we can now also remove drm_dev_to_irq from drm_irq.c.
Reviewed-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The dev->struct_mutex locking in drm_irq.c only protects
dev->irq_enabled. Which isn't really much at all and only prevents
especially nasty ums userspace from concurrently installing the
interrupt handling a few times. Or at least trying.

There are tons of unlocked readers of dev->irqs_enabled in the vblank
wait code (and by extension also in the pageflip code since that uses
the same vblank timestamp engine).

Real modesetting drivers should ensure that nothing can go haywire
with a sane setup teardown sequence. So we only really need this for
the drm_control ioctl, everywhere else this will just paper over
nastiness.

Note that drm/i915 is a bit specially due to the gem+ums combination.
So there we also need to properly protect the entervt and leavevt
ioctls. But it's definitely saner to do everything in one go than to
drop the lock in-between.

Finally there's the gpu reset code in drm/i915. That one's just race
(concurrent userspace calls to for vblank waits of pageflips could
spuriously fail). So wrap it up in with a nice comment since fixing
this is more involved.

v2: Rebase and fix commit message (Thierry)
Reviewed-by: NThierry Reding <treding@nvidia.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If we always initialize kref for the context, even if we are using fake
contexts for hangstats when there is no hw support, we can forgo the
dance to dereference the ctx->obj and inspect whether we are permitted
to use kref inside i915_gem_context_reference() and _unreference().

My ulterior motive here is to improve the debugging of a use-after-free
of ctx->obj. This patch avoids the dereference here and instead forces
the assertion checks associated with kref.

v2: Refactor the fake contexts to being even more like the real
contexts, so that there is much less duplicated and special case code.

v3: Tweaks.
v4: Tweaks, minor.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76671Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Tested-by: Nlu hua <huax.lu@intel.com>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
[Jani: tiny change to backport to drm-intel-fixes.]
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Piglit runner and QA are both looking at the dmesg for
DRM_ERRORs with test cases. Add a flag to control those
when we they are expected from related test cases.

Also add flag to control if contexts should be banned
that introduced the hang. Hangcheck is timer based and
preventing bans by adding sleeps to testcases makes
testing slower.

v2: intel_ring_stopped(), readable comment (Chris)
v3: keep compatibility (Daniel)

References: https://bugs.freedesktop.org/show_bug.cgi?id=75876Signed-off-by: NMika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Clients like i915 need to segregate cache domains within the GTT which
can lead to small amounts of fragmentation. By allocating the uncached
buffers from the bottom and the cacheable buffers from the top, we can
reduce the amount of wasted space and also optimize allocation of the
mappable portion of the GTT to only those buffers that require CPU
access through the GTT.

For other drivers, allocating small bos from one end and large ones
from the other helps improve the quality of fragmentation.

Based on drm_mm work by Chris Wilson.

v3: Changed to use a TTM placement flag
v2: Updated kerneldoc

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: Christian König <deathsimple@vodafone.de>
Signed-off-by: NLauri Kasanen <cand@gmx.com>
Signed-off-by: NDavid Airlie <airlied@redhat.com>

No functional changes.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

On non-LLC platforms, when changing the cache level of an object, we may
need to unbind it so that prefetching across page boundaries does not
cross into a different memory domain. This requires us to unbind
conflicting vma, but we did so iterating over the objects vma in an
unsafe manner (as the list was being modified as we iterated).

The regression was introduced in
commit 3089c6f2
Author: Ben Widawsky <ben@bwidawsk.net>
Date:   Wed Jul 31 17:00:03 2013 -0700

    drm/i915: make caching operate on all address spaces
apparently as far back as v3.12-rc1, but it has only just begun to
trigger real world bug reports.
Reported-and-tested-by: NNikolay Martynov <mar.kolya@gmail.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=76384Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <ben@bwidawsk.net>
Cc: stable@vger.kernel.org
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

When other platforms add runtime PM support they will also need to
disable interrupts, so move the variable to the runtime PM struct.

Also notice that the longer-term goal is to completely kill the
regsave struct, and I even have patches for that.

v2: - Rebase.
v3: - Rebase.
Reviewed-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

DRM drivers share a common address_space across all character-devices of a
single DRM device. This allows simple buffer eviction and mapping-control.
However, DRM core currently waits for the first ->open() on any char-dev
to mark the underlying inode as backing inode of the device. This delayed
initialization causes ugly conditions all over the place:
  if (dev->dev_mapping)
    do_sth();

To avoid delayed initialization and to stop reusing the inode of the
char-dev, we allocate an anonymous inode for each DRM device and reset
filp->f_mapping to it on ->open().
Signed-off-by: NDavid Herrmann <dh.herrmann@gmail.com>

When we change the cache_level for an object we need to make sure
we don't put differing types of snoopable memory too close to each
other on non-LLC machines.

Currently i915_gem_object_set_cache_level() will stop looking when
it finds just one vma that has such a conflict. Drop the bogus break
statement to make sure it will unbind all vmas which need to be moved
around to avoid the conflict.

I suppose this is a theoretical issue as currently we don't enable
ppgtt on non-LLC machines, so each object can only have one vma.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We don't always want to write into main memory with pwrite. The shmem
fast path in particular is used for memory that is cacheable - under
such circumstances forcing the cache eviction is undesirable. As we will
always flush the cache when targeting incoherent buffers, we can rely on
that second pass to apply the cache coherency rules and so benefit from
in-cache copies otherwise.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NBrad Volkin <bradley.d.volkin@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We used to lock individual pages inside the buffer object and so needed
to update the page flags every time. However, we now pin the pages into
the object for the duration of the pwrite/pread (and hopefully much
longer) and so we can forgo the flag updates until we release all the
pages.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: NBrad Volkin <bradley.d.volkin@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

The command parser is going to need the same synchronization and
setup logic, so factor it out for reuse.

v2: Add a check that the object is backed by shmem
Signed-off-by: NBrad Volkin <bradley.d.volkin@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Its last usage outside of i915_gem.c was removed in:

  commit 1f70999f
  Author: Chris Wilson <chris@chris-wilson.co.uk>
  Date:   Mon Jan 27 22:43:07 2014 +0000

     drm/i915: Prevent recursion by retiring requests when the ring is full
Signed-off-by: NDamien Lespiau <damien.lespiau@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

After finding the guilty batch and request, we can use it to find the
process that submitted the batch and then add the culprit into the error
state.

This is a slightly different approach from Ben's in that instead of
adding the extra information into the struct i915_hw_context, we use the
information already captured in struct drm_file which is then referenced
from the request.

v2: Also capture the workaround buffer for gen2, so that we can compare
    its contents against the intended batch for the active request.

v3: Rebase (Mika)
v4: Check for null context (Chris)
    checkpatch warnings fixed

Link: http://lists.freedesktop.org/archives/intel-gfx/2013-August/032280.html
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> (v2)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com> (v4)
Acked-by: NBen Widawsky <ben@bwidawsk.net>
Cc: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In the past, it was possible to have multiple batches per request due to
a stray signal or ENOMEM. As a result we had to scan each active object
(filtered by those having the COMMAND domain) for the one that contained
the ACTHD pointer. This was then made more complicated by the
introduction of ppgtt, whereby ACTHD then pointed into the address space
of the context and so also needed to be taken into account.

This is a fairly robust approach (though the implementation is a little
fragile and depends upon the per-generation setup, registers and
parameters). However, due to the requirements for hangstats, we needed a
robust method for associating batches with a particular request and
having that we can rely upon it for finding the associated batch object
for error capture.

If the batch buffer tracking is not robust enough, that should become
apparent quite quickly through an erroneous error capture. That should
also help to make sure that the runtime reporting to userspace is
robust. It also means that we then report the oldest incomplete batch on
each ring, which can be useful for determining the state of userspace at
the time of a hang.

v2: Use i915_gem_find_active_request (Mika)

v3: remove check for ring->get_seqno, split long lines (Ben)

v4: check that context is available (Chris)
    checkpatch warnings fixed

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com> (v3)
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net> (v3)
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

In place of true activity counting, we walk the list of vma associated
with an object managing each on the vm's active/inactive list everytime
we call move-to-inactive. This depends upon the vma->mm_list being
cleared after unbinding, or else we run into difficulty when tracking
the object in multiple vm's - we see a use-after free and corruption of
the mm_list.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

If we've explicitly stopped the rings for testing purposes, don't ban
the default context. Fixes kms_flip hang tests.
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: NMika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

We currently call intel_mark_idle() too often, as we do so as a
side-effect of processing the request queue. However, we the calls to
intel_mark_idle() are expected to be paired with a call to
intel_mark_busy() (or else we try to idle the hardware by accessing
registers that are already disabled). Make the idle/busy tracking
explicit to prevent the multiple calls.

v2: We can drop some of the complexity in __i915_add_request() as
queue_delayed_work() already behaves as we want (not requeuing the item
if it is already in the queue) and mark_busy/mark_idle imply that the
idle task is inactive.

v3: We do still need to cancel the pending idle task so that it is sent
again after the current busy load completes (not in the middle of it).
Reported-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Tested-by: NPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

One side-effect of the introduction of ppgtt was that we needed to
rebind the object into the appropriate vm (and global gtt in some
peculiar cases). For simplicity this was done twice for every object on
every call to execbuffer. However, that adds a tremendous amount of CPU
overhead (rewriting all the PTE for all objects into WC memory) per
draw. The fix is to push all the decision about which vm to bind into
and when down into the low-level bind routines through hints rather than
performing the bind unconditionally in the execbuffer routine.

Note that this is a regression introduced in the full ppgtt feature
branch, before this we've only done re-bound objects when the relevant
has_(aliasing_ppgtt|global_gtt)_mapping flag was clear. But since
that's per-object and not per-vma that optimization broke.

v2: Split out prep work and unrelated changes.

v3: Bring back functional change around PIN_GLOBAL that I've
accidentally split out.

v4: Remove the temporary hack for the old binding logic to avoid
bisection issues.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=72906
Tested-by: jianx.zhou@intel.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> (v1)
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: NBen Widawsky <ben@bwidawsk.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

This is prep work for reworking the object_pin logic. Atm
it still does a (now redundant) lookup of the vma. The next
patch will fix this.

Split out from Chris vma-bind rework.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Reviewed-by: NJani Nikula <jani.nikula@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

Split out from Chris vma-bind rework.

Jani wondered why this is save, and the reason is that i915_vma_unbind
does all these checks, too. So they're redundant.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <benjamin.widawsky@intel.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

With abitrary pin flags it makes sense to split out a "please bind
this into global gtt" from the "please allocate in the mappable
range".

Use this unconditionally in our global gtt pin helper since this is
what its callers want. Later patches will drop PIN_MAPPABLE where it's
not strictly needed.
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>