As soon as we install fences, we should stop allocating memory
in order to prevent any potential deadlocks.
This is required later on, when we start adding support for
dma-fence annotations.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210323155059.628690-11-maarten.lankhorst@linux.intel.com
The first thing the active retirement worker does is decrement the
i915_active count.
The first thing we do during i915_active_wait is try to increment the
i915_active count, but only if already active [non-zero].
The wait may see that the retirement is already started and so marked the
i915_active as idle, and skip waiting for the retirement handler.
However, the caller of i915_active_wait may immediately free the
i915_active upon returning (e.g. i915_vma_destroy) so we must not return
before the concurrent access from the worker is completed. We must
always flush the worker.
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2473
Fixes: 274cbf20fd ("drm/i915: Push the i915_active.retire into a worker")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: <stable@vger.kernel.org> # v5.5+
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210121232807.16618-1-chris@chris-wilson.co.uk
(cherry picked from commit 977a372e972cb42799746c284035a33c64ebace9)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
New driver:
Cadence MHDP8546 DisplayPort bridge driver
core:
- cross-driver scatterlist cleanups
- devm_drm conversions
- remove drm_dev_init
- devm_drm_dev_alloc conversion
ttm:
- lots of refactoring and cleanups
bridges:
- chained bridge support in more drivers
panel:
- misc new panels
scheduler:
- cleanup priority levels
displayport:
- refactor i915 code into helpers for nouveau
i915:
- split into display and GT trees
- WW locking refactoring in GEM
- execbuf2 extension mechanism
- syncobj timeline support
- GEN 12 HOBL display powersaving
- Rocket Lake display additions
- Disable FBC on Tigerlake
- Tigerlake Type-C + DP improvements
- Hotplug interrupt refactoring
amdgpu:
- Sienna Cichlid updates
- Navy Flounder updates
- DCE6 (SI) support for DC
- Plane rotation enabled
- TMZ state info ioctl
- PCIe DPC recovery support
- DC interrupt handling refactor
- OLED panel fixes
amdkfd:
- add SMI events for thermal throttling
- SMI interface events ioctl update
- process eviction counters
radeon:
- move to dma_ for allocations
- expose sclk via sysfs
msm:
- DSI support for sm8150/sm8250
- per-process GPU pagetable support
- Displayport support
mediatek:
- move HDMI phy driver to PHY
- convert mtk-dpi to bridge API
- disable mt2701 tmds
tegra:
- bridge support
exynos:
- misc cleanups
vc4:
- dual display cleanups
ast:
- cleanups
gma500:
- conversion to GPIOd API
hisilicon:
- misc reworks
ingenic:
- clock handling and format improvements
mcde:
- DSI support
mgag200:
- desktop g200 support
mxsfb:
- i.MX7 + i.MX8M
- alpha plane support
panfrost:
- devfreq support
- amlogic SoC support
ps8640:
- EDID from eDP retrieval
tidss:
- AM65xx YUV workaround
virtio:
- virtio-gpu exported resources
rcar-du:
- R8A7742, R8A774E1 and R8A77961 support
- YUV planar format fixes
- non-visible plane handling
- VSP device reference count fix
- Kconfig fix to avoid displaying disabled options in .config
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Merge tag 'drm-next-2020-10-15' of git://anongit.freedesktop.org/drm/drm
Pull drm updates from Dave Airlie:
"Not a major amount of change, the i915 trees got split into display
and gt trees to better facilitate higher level review, and there's a
major refactoring of i915 GEM locking to use more core kernel concepts
(like ww-mutexes). msm gets per-process pagetables, older AMD SI cards
get DC support, nouveau got a bump in displayport support with common
code extraction from i915.
Outside of drm this contains a couple of patches for hexint
moduleparams which you've acked, and a virtio common code tree that
you should also get via it's regular path.
New driver:
- Cadence MHDP8546 DisplayPort bridge driver
core:
- cross-driver scatterlist cleanups
- devm_drm conversions
- remove drm_dev_init
- devm_drm_dev_alloc conversion
ttm:
- lots of refactoring and cleanups
bridges:
- chained bridge support in more drivers
panel:
- misc new panels
scheduler:
- cleanup priority levels
displayport:
- refactor i915 code into helpers for nouveau
i915:
- split into display and GT trees
- WW locking refactoring in GEM
- execbuf2 extension mechanism
- syncobj timeline support
- GEN 12 HOBL display powersaving
- Rocket Lake display additions
- Disable FBC on Tigerlake
- Tigerlake Type-C + DP improvements
- Hotplug interrupt refactoring
amdgpu:
- Sienna Cichlid updates
- Navy Flounder updates
- DCE6 (SI) support for DC
- Plane rotation enabled
- TMZ state info ioctl
- PCIe DPC recovery support
- DC interrupt handling refactor
- OLED panel fixes
amdkfd:
- add SMI events for thermal throttling
- SMI interface events ioctl update
- process eviction counters
radeon:
- move to dma_ for allocations
- expose sclk via sysfs
msm:
- DSI support for sm8150/sm8250
- per-process GPU pagetable support
- Displayport support
mediatek:
- move HDMI phy driver to PHY
- convert mtk-dpi to bridge API
- disable mt2701 tmds
tegra:
- bridge support
exynos:
- misc cleanups
vc4:
- dual display cleanups
ast:
- cleanups
gma500:
- conversion to GPIOd API
hisilicon:
- misc reworks
ingenic:
- clock handling and format improvements
mcde:
- DSI support
mgag200:
- desktop g200 support
mxsfb:
- i.MX7 + i.MX8M
- alpha plane support
panfrost:
- devfreq support
- amlogic SoC support
ps8640:
- EDID from eDP retrieval
tidss:
- AM65xx YUV workaround
virtio:
- virtio-gpu exported resources
rcar-du:
- R8A7742, R8A774E1 and R8A77961 support
- YUV planar format fixes
- non-visible plane handling
- VSP device reference count fix
- Kconfig fix to avoid displaying disabled options in .config"
* tag 'drm-next-2020-10-15' of git://anongit.freedesktop.org/drm/drm: (1494 commits)
drm/ingenic: Fix bad revert
drm/amdgpu: Fix invalid number of character '{' in amdgpu_acpi_init
drm/amdgpu: Remove warning for virtual_display
drm/amdgpu: kfd_initialized can be static
drm/amd/pm: setup APU dpm clock table in SMU HW initialization
drm/amdgpu: prevent spurious warning
drm/amdgpu/swsmu: fix ARC build errors
drm/amd/display: Fix OPTC_DATA_FORMAT programming
drm/amd/display: Don't allow pstate if no support in blank
drm/panfrost: increase readl_relaxed_poll_timeout values
MAINTAINERS: Update entry for st7703 driver after the rename
Revert "gpu/drm: ingenic: Add option to mmap GEM buffers cached"
drm/amd/display: HDMI remote sink need mode validation for Linux
drm/amd/display: Change to correct unit on audio rate
drm/amd/display: Avoid set zero in the requested clk
drm/amdgpu: align frag_end to covered address space
drm/amdgpu: fix NULL pointer dereference for Renoir
drm/vmwgfx: fix regression in thp code due to ttm init refactor.
drm/amdgpu/swsmu: add interrupt work handler for smu11 parts
drm/amdgpu/swsmu: add interrupt work function
...
This should make it harder for the kernel to corrupt the debug object
descriptor, used to call functions to fixup state and track debug objects,
by moving the structure to read-only memory.
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20200815004027.2046113-3-swboyd@chromium.org
As the conversion between idle-barrier and full i915_active_fence is
already serialised by explicit memory barriers, we can reduce the
spinlock in i915_active_acquire_preallocate_barrier() for finding an
idle-barrier to reuse to an RCU read lock to ensure the fence remains
valid, only taking the spinlock for the update of the rbtree itself.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200731085015.32368-6-chris@chris-wilson.co.uk
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Rather than require the next timeline after idling to match the MRU
before idling, reset the index on the node and allow it to match the
first request. However, this requires cmpxchg(u64) and so is not trivial
on 32b, so for compatibility we just fallback to keeping the cached node
pointing to the MRU timeline.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200731085015.32368-5-chris@chris-wilson.co.uk
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Whenever an i915_active idles, we prune its tree of old fence slots to
prevent a gradual leak should it be used to track many, many timelines.
The downside is that we then have to frequently reallocate the rbtree.
A compromise is that we keep the most recently used fence slot, and
reuse that for the next active reference as that is the most likely
timeline to be reused.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200731085015.32368-4-chris@chris-wilson.co.uk
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Sometimes we have to be very careful not to allocate underneath a mutex
(or spinlock) and yet still want to track activity. Enter
i915_active_acquire_for_context(). This raises the activity counter on
i915_active prior to use and ensures that the fence-tree contains a slot
for the context.
v2: Refactor active_lookup() so it can be called again before/after
locking to resolve contention. Since we protect the rbtree until we
idle, we can do a lockfree lookup, with the caveat that if another
thread performs a concurrent insertion, the rotations from the insert
may cause us to not find our target. A second pass holding the treelock
will find the target if it exists, or the place to perform our
insertion.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200731085015.32368-3-chris@chris-wilson.co.uk
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
If no active callback is defined for i915_active, we do not need to
serialise its enabling with the mutex. We still do only want to call the
debug activate once, and must still serialise with a concurrent retire.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200731085015.32368-2-chris@chris-wilson.co.uk
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
In function i915_active_acquire_preallocate_barrier(), not all
paths have the return value set correctly, and in case of memory
allocation failure, a negative error code should be returned.
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200802115655.25568-1-chris@chris-wilson.co.uk
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Allow the caller to also wait upon the barriers stored in i915_active.
v2: Hook up i915_request_await_active(I915_ACTIVE_AWAIT_BARRIER) as well
for completeness, and avoid the lazy GEM_BUG_ON()!
v3: Pull flush_lazy_signals() under the active-ref protection as it too
walks the rbtree and so we must be careful that we do not free it as we
iterate.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200406155840.1728-2-chris@chris-wilson.co.uk
Later use will require asynchronous waits on the active timelines, but
will not utilize an async wait on the exclusive channel. Make the await
on the exclusive fence explicit in the selection flags.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200406155840.1728-1-chris@chris-wilson.co.uk
For conveniences of callers that just want to use an i915_active to
track a wide array of concurrent timelines, wrap the base i915_active
struct inside a kref. This i915_active will self-destruct after use.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200327112212.16046-2-chris@chris-wilson.co.uk
Keep the engine-pm awake until the next jiffie, to avoid immediate
ping-pong under moderate load. (Forcing the idle barrier excerbates the
moderate load, dramatically increasing the driver overhead.) On the
other hand, delaying the idle-barrier slightly incurs longer rc6-off
and so more power consumption.
Closes: https://gitlab.freedesktop.org/drm/intel/issues/848
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323092841.22240-4-chris@chris-wilson.co.uk
Attaching to the i915_active barrier is a two stage process, and a flush
is only effective when the barrier is activation. Thus it is possible
for us to see a barrier, and attempt to flush, only for our flush to
have no effect. As such, before attempting to activate signaling on the
fence we need to double check it is a fence!
Fixes: d13a317700 ("drm/i915: Flush idle barriers when waiting")
Closes: https://gitlab.freedesktop.org/drm/intel/issues/1333
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200227085723.1961649-1-chris@chris-wilson.co.uk
If we do find ourselves with an idle barrier inside our active while
waiting, attempt to flush it by emitting a pulse using the kernel
context.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Steve Carbonari <steven.carbonari@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200225192206.1107336-1-chris@chris-wilson.co.uk
Take a reference to the previous exclusive fence on the i915_active, as
we wish to add an await to it in the caller (and so must prevent it from
being freed until we have completed that task).
Fixes: e3793468b4 ("drm/i915: Use the async worker to avoid reclaim tainting the ggtt->mutex")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200203094152.4150550-1-chris@chris-wilson.co.uk
On Braswell and Broxton (also known as Valleyview and Apollolake), we
need to serialise updates of the GGTT using the big stop_machine()
hammer. This has the side effect of appearing to lockdep as a possible
reclaim (since it uses the cpuhp mutex and that is tainted by per-cpu
allocations). However, we want to use vm->mutex (including ggtt->mutex)
from within the shrinker and so must avoid such possible taints. For this
purpose, we introduced the asynchronous vma binding and we can apply it
to the PIN_GLOBAL so long as take care to add the necessary waits for
the worker afterwards.
Closes: https://gitlab.freedesktop.org/drm/intel/issues/211
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200130181710.2030251-3-chris@chris-wilson.co.uk
Only the first and the last nodes were being added to
ref->preallocated_barriers.
Renaming variables to make it more easy to read.
Fixes: 8413502238 ("drm/i915/gt: Drop mutex serialisation between context pin/unpin")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200129232345.84512-1-jose.souza@intel.com
As we use a mutex to serialise the first acquire (as it may be a lengthy
operation), but only an atomic decrement for the release, we have to
be careful in case a second thread races and completes both
acquire/release as the first finishes its acquire.
Thread A Thread B
i915_active_acquire i915_active_acquire
atomic_read() == 0 atomic_read() == 0
mutex_lock() mutex_lock()
atomic_read() == 0
ref->active();
atomic_inc()
mutex_unlock()
atomic_read() == 1
i915_active_release
atomic_dec_and_test() -> 0
ref->retire()
atomic_inc() -> 1
mutex_unlock()
So thread A has acquired the ref->active_count but since the ref was
still active at the time, it did not initialise it. By switching the
check inside the mutex to an atomic increment only if already active, we
close the race.
Fixes: c9ad602fea ("drm/i915: Split i915_active.mutex into an irq-safe spinlock for the rbtree")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200126102346.1877661-3-chris@chris-wilson.co.uk
Smatch worries that the engine->mask may be 0 leading to the loop being
shortcircuited leaving the next pointer unset,
drivers/gpu/drm/i915/i915_active.c:667 i915_active_acquire_preallocate_barrier() error: uninitialized symbol 'next'.
Assert that mask is not 0 and smatch can then verify that next must be
initialised before use.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200117110603.2982286-1-chris@chris-wilson.co.uk
The last remaining reason for serialising the pin/unpin of the
intel_context is to ensure that our preallocated wakerefs are not
consumed too early (i.e. the unpin of the previous phase does not emit
the idle barriers for this phase before we even submit). All of the
other operations within the context pin/unpin are supposed to be
atomic... Therefore, we can reduce the serialisation to being just on
the i915_active.preallocated_barriers itself and drop the nested
pin_mutex from intel_context_unpin().
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200106114234.2529613-5-chris@chris-wilson.co.uk
Allocate only an internal intel_context for the kernel_context, forgoing
a global GEM context for internal use as we only require a separate
address space (for our own protection).
Now having weaned GT from requiring ce->gem_context, we can stop
referencing it entirely. This also means we no longer have to create random
and unnecessary GEM contexts for internal use.
GEM contexts are now entirely for tracking GEM clients, and intel_context
the execution environment on the GPU.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Andi Shyti <andi.shyti@intel.com>
Acked-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191221160324.1073045-1-chris@chris-wilson.co.uk
Similar to for i915_active.mutex, we require each class of i915_active
to have distinct lockdep chains as some, but by no means all,
i915_active are used within the shrinker and so have much more severe
usage constraints. By using a lockclass local to i915_active_init() all
i915_active workers have the same lock class, and we may generate false
positives when waiting for the i915_active. If we push the lockclass
into the caller, each class of i915_active will have distinct lockdep
chains.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Acked-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191202140133.2444217-1-chris@chris-wilson.co.uk
The expected downside to commit 58b4c1a07a ("drm/i915: Reduce nested
prepare_remote_context() to a trylock") was that it would need to return
-EAGAIN to userspace in order to resolve potential mutex inversion. Such
an unsightly round trip is unnecessary if we could atomically insert a
barrier into the i915_active_fence, so make it happen.
Currently, we use the timeline->mutex (or some other named outer lock)
to order insertion into the i915_active_fence (and so individual nodes
of i915_active). Inside __i915_active_fence_set, we only need then
serialise with the interrupt handler in order to claim the timeline for
ourselves.
However, if we remove the outer lock, we need to ensure the order is
intact between not only multiple threads trying to insert themselves
into the timeline, but also with the interrupt handler completing the
previous occupant. We use xchg() on insert so that we have an ordered
sequence of insertions (and each caller knows the previous fence on
which to wait, preserving the chain of all fences in the timeline), but
we then have to cmpxchg() in the interrupt handler to avoid overwriting
the new occupant. The only nasty side-effect is having to temporarily
strip off the RCU-annotations to apply the atomic operations, otherwise
the rules are much more conventional!
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=112402
Fixes: 58b4c1a07a ("drm/i915: Reduce nested prepare_remote_context() to a trylock")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191127134527.3438410-1-chris@chris-wilson.co.uk
Previously, we assumed we could use mutex_trylock() within an atomic
context, falling back to a worker if contended. However, such trickery
is illegal inside interrupt context, and so we need to always use a
worker under such circumstances. As we normally are in process context,
we can typically use a plain mutex, and only defer to a work when we
know we are being called from an interrupt path.
Fixes: 51fbd8de87 ("drm/i915/pmu: Atomically acquire the gt_pm wakeref")
References: a0855d24fc ("locking/mutex: Complain upon mutex API misuse in IRQ contexts")
References: https://bugs.freedesktop.org/show_bug.cgi?id=111626
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191120125433.3767149-1-chris@chris-wilson.co.uk
As we want to be able to run inside atomic context for retiring the
i915_active, and we are no longer allowed to abuse mutex_trylock, split
the tree management portion of i915_active.mutex into an irq-safe
spinlock.
References: a0855d24fc ("locking/mutex: Complain upon mutex API misuse in IRQ contexts")
References: https://bugs.freedesktop.org/show_bug.cgi?id=111626
Fixes: 274cbf20fd ("drm/i915: Push the i915_active.retire into a worker")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191114172535.1116-1-chris@chris-wilson.co.uk
To flush idle barriers, and even inflight requests, we want to send a
preemptive 'pulse' along an engine. We use a no-op request along the
pinned kernel_context at high priority so that it should run or else
kick off the stuck requests. We can use this to ensure idle barriers are
immediately flushed, as part of a context cancellation mechanism, or as
part of a heartbeat mechanism to detect and reset a stuck GPU.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191021174339.5389-1-chris@chris-wilson.co.uk
Medium term goal is to eliminate the i915->engine[] array and to get there
we have recently introduced equivalent array in intel_gt. Now we need to
migrate the code further towards this state.
This next step is to eliminate usage of i915->engines[] from the
for_each_engine_masked iterator.
For this to work we also need to use engine->id as index when populating
the gt->engine[] array and adjust the default engine set indexing to use
engine->legacy_idx instead of assuming gt->engines[] indexing.
v2:
* Populate gt->engine[] earlier.
* Check that we don't duplicate engine->legacy_idx
v3:
* Work around the initialization order issue between default_engines()
and intel_engines_driver_register() which sets engine->legacy_idx for
now. It will be fixed properly later.
v4:
* Merge with forgotten v2.5.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20191017161852.8836-1-tvrtko.ursulin@linux.intel.com
Now that we now longer need to guarantee that the active callback is
under the struct_mutex, we can lift it out of the i915_gem_park() and
into the engine parking itself.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-7-chris@chris-wilson.co.uk
Forgo the struct_mutex serialisation for i915_active, and interpose its
own mutex handling for active/retire.
This is a multi-layered sleight-of-hand. First, we had to ensure that no
active/retire callbacks accidentally inverted the mutex ordering rules,
nor assumed that they were themselves serialised by struct_mutex. More
challenging though, is the rule over updating elements of the active
rbtree. Instead of the whole i915_active now being serialised by
struct_mutex, allocations/rotations of the tree are serialised by the
i915_active.mutex and individual nodes are serialised by the caller
using the i915_timeline.mutex (we need to use nested spinlocks to
interact with the dma_fence callback lists).
The pain point here is that instead of a single mutex around execbuf, we
now have to take a mutex for active tracker (one for each vma, context,
etc) and a couple of spinlocks for each fence update. The improvement in
fine grained locking allowing for multiple concurrent clients
(eventually!) should be worth it in typical loads.
v2: Add some comments that barely elucidate anything :(
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-6-chris@chris-wilson.co.uk
As we need to use a mutex to serialise i915_active activation
(because we want to allow the callback to sleep), we need to push the
i915_active.retire into a worker callback in case we get need to retire
from an atomic context.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-5-chris@chris-wilson.co.uk
Replace the struct_mutex requirement for pinning the i915_vma with the
local vm->mutex instead. Note that the vm->mutex is tainted by the
shrinker (we require unbinding from inside fs-reclaim) and so we cannot
allocate while holding that mutex. Instead we have to preallocate
workers to do allocate and apply the PTE updates after we have we
reserved their slot in the drm_mm (using fences to order the PTE writes
with the GPU work and with later unbind).
In adding the asynchronous vma binding, one subtle requirement is to
avoid coupling the binding fence into the backing object->resv. That is
the asynchronous binding only applies to the vma timeline itself and not
to the pages as that is a more global timeline (the binding of one vma
does not need to be ordered with another vma, nor does the implicit GEM
fencing depend on a vma, only on writes to the backing store). Keeping
the vma binding distinct from the backing store timelines is verified by
a number of async gem_exec_fence and gem_exec_schedule tests. The way we
do this is quite simple, we keep the fence for the vma binding separate
and only wait on it as required, and never add it to the obj->resv
itself.
Another consequence in reducing the locking around the vma is the
destruction of the vma is no longer globally serialised by struct_mutex.
A natural solution would be to add a kref to i915_vma, but that requires
decoupling the reference cycles, possibly by introducing a new
i915_mm_pages object that is own by both obj->mm and vma->pages.
However, we have not taken that route due to the overshadowing lmem/ttm
discussions, and instead play a series of complicated games with
trylocks to (hopefully) ensure that only one destruction path is called!
v2: Add some commentary, and some helpers to reduce patch churn.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20191004134015.13204-4-chris@chris-wilson.co.uk
The request->timeline is only valid until the request is retired (i.e.
before it is completed). Upon retiring the request, the context may be
unpinned and freed, and along with it the timeline may be freed. We
therefore need to be very careful when chasing rq->timeline that the
pointer does not disappear beneath us. The vast majority of users are in
a protected context, either during request construction or retirement,
where the timeline->mutex is held and the timeline cannot disappear. It
is those few off the beaten path (where we access a second timeline) that
need extra scrutiny -- to be added in the next patch after first adding
the warnings about dangerous access.
One complication, where we cannot use the timeline->mutex itself, is
during request submission onto hardware (under spinlocks). Here, we want
to check on the timeline to finalize the breadcrumb, and so we need to
impose a second rule to ensure that the request->timeline is indeed
valid. As we are submitting the request, it's context and timeline must
be pinned, as it will be used by the hardware. Since it is pinned, we
know the request->timeline must still be valid, and we cannot submit the
idle barrier until after we release the engine->active.lock, ergo while
submitting and holding that spinlock, a second thread cannot release the
timeline.
v2: Don't be lazy inside selftests; hold the timeline->mutex for as long
as we need it, and tidy up acquiring the timeline with a bit of
refactoring (i915_active_add_request)
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190919111912.21631-1-chris@chris-wilson.co.uk
The point of debug_object_activate is to mark the first, and only the
first, acquisition. The object then remains active until the last
release. However, we marked up all successful first acquires even though
we allowed concurrent parties to try and acquire the i915_active
simultaneously (serialised by the i915_active.mutex).
Testcase: igt/gem_mmap_gtt/fault-concurrent
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190827132631.18627-1-chris@chris-wilson.co.uk
As every i915_active_request should be serialised by a dedicated lock,
i915_active consists of a tree of locks; one for each node. Markup up
the i915_active_request with what lock is supposed to be guarding it so
that we can verify that the serialised updated are indeed serialised.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190816121000.8507-2-chris@chris-wilson.co.uk
We use the request pointer inside the i915_active_node as the indicator
of the barrier's status; we mark it as used during
i915_request_add_active_barriers(), and search for an available barrier
in reuse_idle_barrier(). That check must be carefully serialised to
ensure we do use an engine for the barrier and not just a random
pointer. (Along the other reuse path, we are fully serialised by the
timeline->mutex.) The acquisition of the barrier itself is ordered through
the strong memory barrier in llist_del_all().
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111397
Fixes: d8af05ff38 ("drm/i915: Allow sharing the idle-barrier from other kernel requests")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190813200905.11369-1-chris@chris-wilson.co.uk
Move the timeline from being inside the intel_ring to intel_context
itself. This saves much pointer dancing and makes the relations of the
context to its timeline much clearer.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190809182518.20486-4-chris@chris-wilson.co.uk
By placing our idle-barriers in the i915_active fence tree, we expose
those for reuse by other components that are issuing requests along the
kernel_context. Reusing the proto-barrier active_node is perfectly fine
as the new request implies a context-switch, and so an opportune point
to run the idle-barrier. However, the proto-barrier is not equivalent
to a normal active_node and care must be taken to avoid dereferencing the
ERR_PTR used as its request marker.
v2: Comment the more egregious cheek
v3: A glossary!
Reported-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Fixes: ce476c80b8 ("drm/i915: Keep contexts pinned until after the next kernel context switch")
Fixes: a9877da2d6 ("drm/i915/oa: Reconfigure contexts on the fly")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190802100015.1281-1-chris@chris-wilson.co.uk
for_each_engine_masked caches the engine mask but what does the caller
know.
Cache it explicitly for clarity and while at it correct the type to match.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20190725125056.11942-1-tvrtko.ursulin@linux.intel.com
