This change adds the dma_resv_usage enum and allows us to specify why a
dma_resv object is queried for its containing fences.
Additional to that a dma_resv_usage_rw() helper function is added to aid
retrieving the fences for a read or write userspace submission.
This is then deployed to the different query functions of the dma_resv
object and all of their users. When the write paratermer was previously
true we now use DMA_RESV_USAGE_WRITE and DMA_RESV_USAGE_READ otherwise.
v2: add KERNEL/OTHER in separate patch
v3: some kerneldoc suggestions by Daniel
v4: some more kerneldoc suggestions by Daniel, fix missing cases lost in
the rebase pointed out by Bas.
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220407085946.744568-2-christian.koenig@amd.com
Rather than stealing bits from i915_sw_fence function pointer use
separate fields for function pointer and flags. If using two different
fields, the 4 byte alignment for the i915_sw_fence function pointer can
also be dropped.
v2:
(CI)
- Set new function field rather than flags in __i915_sw_fence_init
v3:
(Tvrtko)
- Remove BUG_ON(!fence->flags) in reinit as that will now blow up
- Only define fence->flags if CONFIG_DRM_I915_SW_FENCE_CHECK_DAG is
defined
v4:
- Rebase, resend for CI
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211116194929.10211-1-matthew.brost@intel.com
If we have a set of active engines marked as being non-persistent, we
lose track of those if the user replaces those engines with
I915_CONTEXT_PARAM_ENGINES. As part of our uABI contract is that
non-persistent requests are terminated if they are no longer being
tracked by the user's context (in order to prevent a lost request
causing an untracked and so unstoppable GPU hang), we need to apply the
same context cancellation upon changing engines.
v2: Track stale engines[] so we only reap at context closure.
v3: Tvrtko spotted races with closing contexts and set-engines, so add a
veneer of kill-everything paranoia to clean up after losing a race.
Fixes: a0e047156c ("drm/i915/gem: Make context persistence optional")
Testcase: igt/gem_ctx_peristence/replace
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/20200211144831.1011498-1-chris@chris-wilson.co.uk
As we start peeking into requests for longer and longer, e.g.
incorporating use of spinlocks when only protected by an
rcu_read_lock(), we need to be careful in how we reset the request when
recycling and need to preserve any barriers that may still be in use as
the request is reset for reuse.
Quoting Linus Torvalds:
> If there is refcounting going on then why use SLAB_TYPESAFE_BY_RCU?
.. because the object can be accessed (by RCU) after the refcount has
gone down to zero, and the thing has been released.
That's the whole and only point of SLAB_TYPESAFE_BY_RCU.
That flag basically says:
"I may end up accessing this object *after* it has been free'd,
because there may be RCU lookups in flight"
This has nothing to do with constructors. It's ok if the object gets
reused as an object of the same type and does *not* get
re-initialized, because we're perfectly fine seeing old stale data.
What it guarantees is that the slab isn't shared with any other kind
of object, _and_ that the underlying pages are free'd after an RCU
quiescent period (so the pages aren't shared with another kind of
object either during an RCU walk).
And it doesn't necessarily have to have a constructor, because the
thing that a RCU walk will care about is
(a) guaranteed to be an object that *has* been on some RCU list (so
it's not a "new" object)
(b) the RCU walk needs to have logic to verify that it's still the
*same* object and hasn't been re-used as something else.
In contrast, a SLAB_TYPESAFE_BY_RCU memory gets free'd and re-used
immediately, but because it gets reused as the same kind of object,
the RCU walker can "know" what parts have meaning for re-use, in a way
it couidn't if the re-use was random.
That said, it *is* subtle, and people should be careful.
> So the re-use might initialize the fields lazily, not necessarily using a ctor.
If you have a well-defined refcount, and use "atomic_inc_not_zero()"
to guard the speculative RCU access section, and use
"atomic_dec_and_test()" in the freeing section, then you should be
safe wrt new allocations.
If you have a completely new allocation that has "random stale
content", you know that it cannot be on the RCU list, so there is no
speculative access that can ever see that random content.
So the only case you need to worry about is a re-use allocation, and
you know that the refcount will start out as zero even if you don't
have a constructor.
So you can think of the refcount itself as always having a zero
constructor, *BUT* you need to be careful with ordering.
In particular, whoever does the allocation needs to then set the
refcount to a non-zero value *after* it has initialized all the other
fields. And in particular, it needs to make sure that it uses the
proper memory ordering to do so.
NOTE! One thing to be very worried about is that re-initializing
whatever RCU lists means that now the RCU walker may be walking on the
wrong list so the walker may do the right thing for this particular
entry, but it may miss walking *other* entries. So then you can get
spurious lookup failures, because the RCU walker never walked all the
way to the end of the right list. That ends up being a much more
subtle bug.
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/20191122094924.629690-1-chris@chris-wilson.co.uk
We need the rename of reservation_object to dma_resv.
The solution on this merge came from linux-next:
From: Stephen Rothwell <sfr@canb.auug.org.au>
Date: Wed, 14 Aug 2019 12:48:39 +1000
Subject: [PATCH] drm: fix up fallout from "dma-buf: rename reservation_object to dma_resv"
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
---
drivers/gpu/drm/i915/gt/intel_engine_pool.c | 8 ++++----
3 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_pool.c b/drivers/gpu/drm/i915/gt/intel_engine_pool.c
index 03d90b49584a..4cd54c569911 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_pool.c
+++ b/drivers/gpu/drm/i915/gt/intel_engine_pool.c
@@ -43,12 +43,12 @@ static int pool_active(struct i915_active *ref)
{
struct intel_engine_pool_node *node =
container_of(ref, typeof(*node), active);
- struct reservation_object *resv = node->obj->base.resv;
+ struct dma_resv *resv = node->obj->base.resv;
int err;
- if (reservation_object_trylock(resv)) {
- reservation_object_add_excl_fence(resv, NULL);
- reservation_object_unlock(resv);
+ if (dma_resv_trylock(resv)) {
+ dma_resv_add_excl_fence(resv, NULL);
+ dma_resv_unlock(resv);
}
err = i915_gem_object_pin_pages(node->obj);
which is a simplified version from a previous one which had:
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Previously, our view has been always to run the engines independently
within a context. (Multiple engines happened before we had contexts and
timelines, so they always operated independently and that behaviour
persisted into contexts.) However, at the user level the context often
represents a single timeline (e.g. GL contexts) and userspace must
ensure that the individual engines are serialised to present that
ordering to the client (or forgot about this detail entirely and hope no
one notices - a fair ploy if the client can only directly control one
engine themselves ;)
In the next patch, we will want to construct a set of engines that
operate as one, that have a single timeline interwoven between them, to
present a single virtual engine to the user. (They submit to the virtual
engine, then we decide which engine to execute on based.)
To that end, we want to be able to create contexts which have a single
timeline (fence context) shared between all engines, rather than multiple
timelines.
v2: Move the specialised timeline ordering to its own function.
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/20190322092325.5883-4-chris@chris-wilson.co.uk
Having introduced per-context seqno, we now have a means to identity
progress across the system without feel of rollback as befell the
global_seqno. That is we can program a MI_SEMAPHORE_WAIT operation in
advance of submission safe in the knowledge that our target seqno and
address is stable.
However, since we are telling the GPU to busy-spin on the target address
until it matches the signaling seqno, we only want to do so when we are
sure that busy-spin will be completed quickly. To achieve this we only
submit the request to HW once the signaler is itself executing (modulo
preemption causing us to wait longer), and we only do so for default and
above priority requests (so that idle priority tasks never themselves
hog the GPU waiting for others).
As might be reasonably expected, HW semaphores excel in inter-engine
synchronisation microbenchmarks (where the 3x reduced latency / increased
throughput more than offset the power cost of spinning on a second ring)
and have significant improvement (can be up to ~10%, most see no change)
for single clients that utilize multiple engines (typically media players
and transcoders), without regressing multiple clients that can saturate
the system or changing the power envelope dramatically.
v3: Drop the older NEQ branch, now we pin the signaler's HWSP anyway.
v4: Tell the world and include it as part of scheduler caps.
Testcase: igt/gem_exec_whisper
Testcase: igt/benchmarks/gem_wsim
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/20190301170901.8340-3-chris@chris-wilson.co.uk
drm-misc-next for 5.1:
UAPI Changes:
Cross-subsystem Changes:
- Turn dma-buf fence sequence numbers into 64 bit numbers
Core Changes:
- Move to a common helper for the DP MST hotplug for radeon, i915 and
amdgpu
- i2c improvements for drm_dp_mst
- Removal of drm_syncobj_cb
- Introduction of an helper to create and attach the TV margin properties
Driver Changes:
- Improve cache flushes for v3d
- Reflection support for vc4
- HDMI overscan support for vc4
- Add implicit fencing support for rockchip and sun4i
- Switch to generic fbdev emulation for virtio
Signed-off-by: Dave Airlie <airlied@redhat.com>
[airlied: applied amdgpu merge fixup]
From: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190107180333.amklwycudbsub3s5@flea
For a lot of use cases we need 64bit sequence numbers. Currently drivers
overload the dma_fence structure to store the additional bits.
Stop doing that and make the sequence number in the dma_fence always
64bit.
For compatibility with hardware which can do only 32bit sequences the
comparisons in __dma_fence_is_later only takes the lower 32bits as significant
when the upper 32bits are all zero.
v2: change the logic in __dma_fence_is_later
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Link: https://patchwork.freedesktop.org/patch/266927/
If an asynchronous wait on a foriegn fence, we print a warning
indicating which fence was not signaled. As i915_sw_fences become more
common, include the debug hint (the symbol-name of the target) to help
identify the waiter. E.g.
[ 31.968144] Asynchronous wait on fence sw_sync:gem_eio:1 timed out (hint:submit_notify [i915])
We also want to downgrade from a warning to a notice (normal but
significant condition) as the timeout is imposed and controlled by the
caller (i.e. it is deliberate) and can be provoked by userspace.
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/20180914124007.18790-1-chris@chris-wilson.co.uk
For some selftests, we want to issue requests but delay them going to
hardware. Furthermore, we don't want those requests to block
indefinitely (or else we may hang the driver and block testing) so we
want to employ a timeout. So naturally we want a fence that is
automatically signaled by a timer.
v2: Add kselftests.
v3: Limit the API available to selftests; there isn't an overwhelming
reason to export it universally.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171012125726.14736-2-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
A fence may be signaled from any context, including from inside a timer.
One example is timer_i915_sw_fence_wake() which is used to provide a
safety-net when waiting on an external fence. If the external fence is
not signaled within a timely fashion, we signal our fence on its behalf,
and so we then may process subsequent fences in the chain from within
that timer context.
Given that dma_i915_sw_fence_wake() may be from inside a timer, we cannot
then use del_timer_sync() as that requires the timer lock for itself. To
circumvent this, while trying to keep the signal propagation as low
latency as possible, move the completion into a worker and use a bit of
atomic switheroo to serialise the timer-callback and the dma-callback.
Testcase: igt/gem_eio/in-flight-external
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170911084135.22903-3-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Pull drm updates from Dave Airlie:
"This is the main pull request for the drm, I think I've got one later
driver pull for mediatek SoC driver, I'm undecided on if it needs to
go to you yet.
Otherwise summary below:
Core drm:
- Atomic add driver private objects
- Deprecate preclose hook in modern drivers
- MST bandwidth tracking
- Use kvmalloc in more places
- Add mode_valid hook for crtc/encoder/bridge
- Reduce sync_file construction time
- Documentation updates
- New DRM synchronisation object support
New drivers:
- pl111 - pl111 CLCD display controller
Panel:
- Innolux P079ZCA panel driver
- Add NL12880B20-05, NL192108AC18-02D, P320HVN03 panels
- panel-samsung-s6e3ha2: Add s6e3hf2 panel support
i915:
- SKL+ watermark fixes
- G4x/G33 reset improvements
- DP AUX backlight improvements
- Buffer based GuC/host communication
- New getparam for (sub)slice infomation
- Cannonlake and Coffeelake initial patches
- Execbuf optimisations
radeon/amdgpu:
- Lots of Vega10 bug fixes
- Preliminary raven support
- KIQ support for compute rings
- MEC queue management rework
- DCE6 Audio support
- SR-IOV improvements
- Better radeon/amdgpu selection support
nouveau:
- HDMI stereoscopic support
- Display code rework for >= GM20x GPUs
msm:
- GEM rework for fine-grained locking
- Per-process pagetable work
- HDMI fixes for Snapdragon 820.
vc4:
- Remove 256MB CMA limit from vc4
- Add out-fence support
- Add support for cygnus
- Get/set tiling ioctls support
- Add T-format tiling support for scanout
zte:
- add VGA support.
etnaviv:
- Thermal throttle support for newer GPUs
- Restore userspace buffer cache performance
- dma-buf sync fix
stm:
- add stm32f429 display support
exynos:
- Rework vblank handling
- Fixup sw-trigger code
sun4i:
- V3s display engine support
- HDMI support for older SoCs
- Preliminary work on dual-pipeline SoCs.
rcar-du:
- VSP work
imx-drm:
- Remove counter load enable from PRE
- Double read/write reduction flag support
tegra:
- Documentation for the host1x and drm driver.
- Lots of staging ioctl fixes due to grate project work.
omapdrm:
- dma-buf fence support
- TILER rotation fixes"
* tag 'drm-for-v4.13' of git://people.freedesktop.org/~airlied/linux: (1270 commits)
drm: Remove unused drm_file parameter to drm_syncobj_replace_fence()
drm/amd/powerplay: fix bug fail to remove sysfs when rmmod amdgpu.
amdgpu: Set cik/si_support to 1 by default if radeon isn't built
drm/amdgpu/gfx9: fix driver reload with KIQ
drm/amdgpu/gfx8: fix driver reload with KIQ
drm/amdgpu: Don't call amd_powerplay_destroy() if we don't have powerplay
drm/ttm: Fix use-after-free in ttm_bo_clean_mm
drm/amd/amdgpu: move get memory type function from early init to sw init
drm/amdgpu/cgs: always set reference clock in mode_info
drm/amdgpu: fix vblank_time when displays are off
drm/amd/powerplay: power value format change for Vega10
drm/amdgpu/gfx9: support the amdgpu.disable_cu option
drm/amd/powerplay: change PPSMC_MSG_GetCurrPkgPwr for Vega10
drm/amdgpu: Make amdgpu_cs_parser_init static (v2)
drm/amdgpu/cs: fix a typo in a comment
drm/amdgpu: Fix the exported always on CU bitmap
drm/amdgpu/gfx9: gfx_v9_0_enable_gfx_static_mg_power_gating() can be static
drm/amdgpu/psp: upper_32_bits/lower_32_bits for address setup
drm/amd/powerplay/cz: print message if smc message fails
drm/amdgpu: fix typo in amdgpu_debugfs_test_ib_init
...
So I've noticed a number of instances where it was not obvious from the
code whether ->task_list was for a wait-queue head or a wait-queue entry.
Furthermore, there's a number of wait-queue users where the lists are
not for 'tasks' but other entities (poll tables, etc.), in which case
the 'task_list' name is actively confusing.
To clear this all up, name the wait-queue head and entry list structure
fields unambiguously:
struct wait_queue_head::task_list => ::head
struct wait_queue_entry::task_list => ::entry
For example, this code:
rqw->wait.task_list.next != &wait->task_list
... is was pretty unclear (to me) what it's doing, while now it's written this way:
rqw->wait.head.next != &wait->entry
... which makes it pretty clear that we are iterating a list until we see the head.
Other examples are:
list_for_each_entry_safe(pos, next, &x->task_list, task_list) {
list_for_each_entry(wq, &fence->wait.task_list, task_list) {
... where it's unclear (to me) what we are iterating, and during review it's
hard to tell whether it's trying to walk a wait-queue entry (which would be
a bug), while now it's written as:
list_for_each_entry_safe(pos, next, &x->head, entry) {
list_for_each_entry(wq, &fence->wait.head, entry) {
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rename:
wait_queue_t => wait_queue_entry_t
'wait_queue_t' was always a slight misnomer: its name implies that it's a "queue",
but in reality it's a queue *entry*. The 'real' queue is the wait queue head,
which had to carry the name.
Start sorting this out by renaming it to 'wait_queue_entry_t'.
This also allows the real structure name 'struct __wait_queue' to
lose its double underscore and become 'struct wait_queue_entry',
which is the more canonical nomenclature for such data types.
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
My original intention was for i915_sw_fence to be the base class and
provide the reference count for the container. This was from starting
with a design to handle async_work. In practice, for i915 we embed
fences into structs which have their own independent reference counting,
making the i915_sw_fence.kref duplicitous. If we remove the kref, we
remove the i915_sw_fence's ability to free itself and its independence,
it can only exist within a container and must be supplied with a
callback to handle its release.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170517121007.27224-1-chris@chris-wilson.co.uk
Add the tracking required to enable debugobjects for fences to improve
error detection in BAT. The debugobject interface lets us track the
lifetime and phases of the fences even while being embedded into larger
structs, i.e. to check they are not used after they have been released.
v2: Don't populate the stubs, debugobjects checks for a NULL pointer and
treats it equivalently.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161125131718.20978-4-chris@chris-wilson.co.uk
Localise the static struct lock_class_key to the caller of
i915_sw_fence_init() so that we create a lock_class instance for each
unique sw_fence rather than all sw_fences sharing the same
lock_class. This eliminate some lockdep false positive when using fences
from within fence callbacks.
For the relatively small number of fences currently in use [2], this adds
160 bytes of unused text/code when lockdep is disabled. This seems
quite high, but fully reducing it via ifdeffery is also quite ugly.
Removing the #fence strings saves 72 bytes with just a single #ifdef.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161114204105.29171-1-chris@chris-wilson.co.uk
This is really a core kernel struct in disguise until we can finally
place it in kernel/. There is an immediate need for a fence collection
mechanism that is more flexible than fence-array, in particular being
able to easily drive request submission via events (and not just
interrupt driven). The same mechanism would be useful for handling
nonblocking and asynchronous atomic modesets, parallel execution and
more, but for the time being just create a local sw fence for execbuf.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160909131201.16673-1-chris@chris-wilson.co.uk
