For legacy contexts we employ an optimisation to only flush the context
when binding into the global GTT. This avoids stalling on the GPU when
reloading an active context. Wrap this detail up into a helper and
export it for a potential third user. (Longer term, context pinning
needs to be reworked as the current handling of switch context pins too
late and so risks eviction and corrupting the request. Plans, plans,
plans.)
v2: Expand the comment explaining the optimisation for avoiding the
stall on active contexts.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/20161030132820.32163-1-chris@chris-wilson.co.uk
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
There's no need to keep a duplicate skl_pipe_wm around any more,
everything can be discovered from crtc_state, which we pass around
correctly now even in case of plane disable.
The copy in intel_crtc->wm.skl.active is equal to
crtc_state->wm.skl.optimal after the atomic commit completes.
It's useful for two-step watermark programming, but not required for
gen9+ which does it in a single step. We can pull the old allocation
from old_crtc_state.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477489299-25777-9-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Move calculating minimum allocations to a helper, which cleans up the
code some more. The cursor is still allocated in advance because it
doesn't count towards data rate and should always be reserved.
changes since v1:
- Change comment to have a extra opening line. (Matt)
- Rebase to remove unused plane->pipe == pipe, handled by the iterator
now. (Paulo)
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477489299-25777-7-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
It's only used in one function, and can be calculated without caching it
in the global struct by using drm_atomic_crtc_state_for_each_plane_state.
There are loops over all planes, including planes that don't exist.
This is harmless, because data_rate will always be 0 for them and we
never program them when updating watermarks.
Changes since v1:
- Rename rate back to data_rate, and change array name to
plane_data_rate. (Matt)
- Remove whitespace. (Paulo)
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477489299-25777-5-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Using for_each_intel_plane_on_crtc will allow us to find all allocations
that may have changed, not just the one added by the atomic state.
This will print changes to plane allocations for crtc's when some
planes are not added to the atomic state.
Changes since v1:
- Rephrase commit message. (Ville)
- Use plane->base.id and plane->name to kill off cursor special
case. (Ville)
- Add intel_crtc to prevent a line wrap. (Paulo)
- Line wrap debug messages.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/c9f7dc1a-d23a-7c16-b2b7-1c23dd07ed35@linux.intel.com
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
I'm planning on getting rid of all obj->state dereferences,
and replace thhem with accessor functions.
Remove this one early, they're equivalent because removed
planes are already part of the state, else they could not
have been removed.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477489299-25777-3-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Caching is not required, drm_atomic_crtc_state_for_each_plane_state can
be used to inspect the states of all planes assigned to the CRTC even
if they are not part of _state, so we can just recalculate every time.
Changes since v1:
- Remove plane->pipe checks, they're implied by the macros.
- Split unrelated changes to a separate commit.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477489299-25777-2-git-send-email-maarten.lankhorst@linux.intel.com
Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
The shrinker may appear to recurse into obj->mm.lock as the shrinker may
be called from a direct reclaim path whilst handling get_pages. We
filter out recursing on the same obj->mm.lock by inspecting
obj->mm.pages, but we do want to take the lock on a second object in
order to reap their pages. lockdep spots the recursion on the same
lockclass and needs annotation to avoid a false positive. To keep the
two paths distinct, create an enum to indicate which subclass of
obj->mm.lock we are using. This removes the false positive and avoids
masking real bugs.
Suggested-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161101121134.27504-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
With full-ppgtt one of the main bottlenecks is the lookup of the VMA
underneath the object. For execbuf there is merit in having a very fast
direct lookup of ctx:handle to the vma using a hashtree, but that still
leaves a large number of other lookups. One way to speed up the lookup
would be to use a rhashtable, but that requires extra allocations and
may exhibit poor worse case behaviour. An alternative is to use an
embedded rbtree, i.e. no extra allocations and deterministic behaviour,
but at the slight cost of O(lgN) lookups (instead of O(1) for
rhashtable). The major of such tree will be very shallow and so not much
slower, and still scales much, much better than the current unsorted
list.
v2: Bump vma_compare() to return a long, as we return the result of
comparing two pointers.
References: https://bugs.freedesktop.org/show_bug.cgi?id=87726
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161101115400.15647-1-chris@chris-wilson.co.uk
If we have a tiled object and an unknown CPU swizzle pattern, we pin the
pages to prevent the object from being swapped out (and us corrupting
the contents as we do not know the access pattern and so cannot convert
it to linear and back to tiled on reuse). This requires us to remember
to drop the extra pinning when freeing the object, or else we trigger
warnings about the pin leak. In commit fbbd37b36f ("drm/i915: Move
object release to a freelist + worker"), the object free path was
deferred to a worker, but the unpinning of the quirk, along with marking
the object as reclaimable, was left on the immediate path (so that if
required we could reclaim the pages under memory pressure as early as
possible). However, this split introduced a bug where the pages were no
longer being unpinned if they were marked as unneeded.
[ 231.800401] WARNING: CPU: 1 PID: 90 at drivers/gpu/drm/i915/i915_gem.c:4275 __i915_gem_free_objects+0x326/0x3c0 [i915]
[ 231.800403] WARN_ON(i915_gem_object_has_pinned_pages(obj))
[ 231.800405] Modules linked in:
[ 231.800406] snd_hda_intel i915 snd_hda_codec_generic mei_me snd_hda_codec coretemp snd_hwdep mei lpc_ich snd_hda_core snd_pcm e1000e ptp pps_core [last unloaded: i915]
[ 231.800426] CPU: 1 PID: 90 Comm: kworker/1:4 Tainted: G U 4.9.0-rc2-CI-CI_DRM_1780+ #1
[ 231.800428] Hardware name: LENOVO 7465CTO/7465CTO, BIOS 6DET44WW (2.08 ) 04/22/2009
[ 231.800456] Workqueue: events __i915_gem_free_work [i915]
[ 231.800459] ffffc9000034fc80 ffffffff8142dd65 ffffc9000034fcd0 0000000000000000
[ 231.800465] ffffc9000034fcc0 ffffffff8107e4e6 000010b300000001 0000000000001000
[ 231.800469] ffff88011d3db740 ffff880130ef0000 0000000000000000 ffff880130ef5ea0
[ 231.800474] Call Trace:
[ 231.800479] [<ffffffff8142dd65>] dump_stack+0x67/0x92
[ 231.800484] [<ffffffff8107e4e6>] __warn+0xc6/0xe0
[ 231.800487] [<ffffffff8107e54a>] warn_slowpath_fmt+0x4a/0x50
[ 231.800491] [<ffffffff811d12ac>] ? kmem_cache_free+0x2dc/0x340
[ 231.800520] [<ffffffffa009ef36>] __i915_gem_free_objects+0x326/0x3c0 [i915]
[ 231.800548] [<ffffffffa009effe>] __i915_gem_free_work+0x2e/0x50 [i915]
[ 231.800552] [<ffffffff8109c27c>] process_one_work+0x1ec/0x6b0
[ 231.800555] [<ffffffff8109c1f6>] ? process_one_work+0x166/0x6b0
[ 231.800558] [<ffffffff8109c789>] worker_thread+0x49/0x490
[ 231.800561] [<ffffffff8109c740>] ? process_one_work+0x6b0/0x6b0
[ 231.800563] [<ffffffff8109c740>] ? process_one_work+0x6b0/0x6b0
[ 231.800566] [<ffffffff810a2aab>] kthread+0xeb/0x110
[ 231.800569] [<ffffffff810a29c0>] ? kthread_park+0x60/0x60
[ 231.800573] [<ffffffff818164a7>] ret_from_fork+0x27/0x40
Moving to a separate flag for tracking the quirked pin is overkill for
the bug (since we only have to interchange the two tests in
i915_gem_free_object) but it does reduce a complicated test on all
objects and provide a sanitycheck for uncommon code paths.
Fixes: fbbd37b36f ("drm/i915: Move object release to a freelist + worker")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20161101100317.11129-2-chris@chris-wilson.co.uk
During shrinking, we walk over the list of objects searching for
victims. Any that are not removed are put back into the global list.
Currently, they are put back in order (at the front) which means they
will be first to be scanned again. If we instead move them to the rear
of the list, we will scan new potential victims on the next pass and
waste less time rescanning unshrinkable objects. Normally the lists are
kept in rough order to shrinking (with object least frequently used at
the start), by moving just scanned objects to the rear we are
acknowledging that they are still in use.
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/20161101084843.3961-3-chris@chris-wilson.co.uk
Due to the plane->index not getting readjusted in drm_plane_cleanup(),
we can't continue initialization of some plane/crtc init fails.
Well, we sort of could I suppose if we left all initialized planes on
the list, but that would expose those planes to userspace as well.
But for crtcs the situation is even worse since we assume that
pipe==crtc index occasionally, so we can't really deal with a partially
initialize set of crtcs.
So seems safest to just abort the entire thing if anything goes wrong.
All the failure paths here are kmalloc()s anyway, so it seems unlikely
we'd get very far if these start failing.
v2: Add (enum plane) case to silence gcc
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477411083-19255-4-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
One of the CI machines began to run into issues with the hpd poller
suddenly waking up in the midst of the late suspend phase. It looks like
this is getting caused by the fact we now deinitialize power wells in
late suspend, which means that intel_hpd_poll_init() gets called in late
suspend causing polling to get re-enabled. So, when deinitializing power
wells on valleyview we now refrain from enabling polling in the midst of
suspend.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=98040
Fixes: 19625e85c6 ("drm/i915: Enable polling when we don't have hpd")
Signed-off-by: Lyude <lyude@redhat.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Jani Saarinen <jani.saarinen@intel.com>
Cc: Petry Latvala <petri.latvala@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1477499769-1966-1-git-send-email-lyude@redhat.com
With the infrastructure converted over to tracking multiple timelines in
the GEM API whilst preserving the efficiency of using a single execution
timeline internally, we can now assign a separate timeline to every
context with full-ppgtt.
v2: Add a comment to indicate the xfer between timelines upon submission.
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/20161028125858.23563-35-chris@chris-wilson.co.uk
Defer the assignment of the global seqno on a request to its submission.
In the next patch, we will only allocate the global seqno at that time,
here we are just enabling the wait-for-submission before wait-for-seqno
paths.
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/20161028125858.23563-34-chris@chris-wilson.co.uk
A restriction on our global seqno is that they cannot wrap, and that we
cannot use the value 0. This allows us to detect when a request has not
yet been submitted, its global seqno is still 0, and ensures that
hardware semaphores are monotonic as required by older hardware. To
meet these restrictions when we defer the assignment of the global
seqno, we must check that we have an available slot in the global seqno
space during request construction. If that test fails, we wait for all
requests to be completed and reset the hardware back to 0.
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/20161028125858.23563-33-chris@chris-wilson.co.uk
This will be used for communicating issues with this context to
userspace, so we want to identify the parent process and the individual
context. Note that the name isn't quite unique, it makes the presumption
of there only being a single device fd per process.
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/20161028125858.23563-31-chris@chris-wilson.co.uk
Currently we try to reduce the number of synchronisations (now the
number of requests we need to wait upon) by noting that if we have
earlier waited upon a request, all subsequent requests in the timeline
will be after the wait. This only applies to requests in this timeline,
as other timelines will not be ordered by that waiter.
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/20161028125858.23563-30-chris@chris-wilson.co.uk
Move the actual emission of the breadcrumb for closing the request from
i915_add_request() to the submit callback. (It can be moved later when
required.) This allows us to defer the allocation of the global_seqno
from request construction to actual submission, allowing us to emit the
requests out of order (wrt to the order of their construction, they
still will only be executed one all of their dependencies are resolved
including that all earlier requests on their timeline have been
submitted.) We have to specialise how we then emit the request in order
to write into the preallocated space, rather than at the tail of the
ringbuffer (which will have been advanced by the addition of new
requests).
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/20161028125858.23563-29-chris@chris-wilson.co.uk
In the next patch, we will use deferred breadcrumb emission. That requires
reserving sufficient space in the ringbuffer to emit the breadcrumb, which
first requires us to know how large the breadcrumb is.
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/20161028125858.23563-28-chris@chris-wilson.co.uk
Now that the emission of the request tail and its submission to hardware
are two separate steps, engine->emit_request() is confusing.
engine->emit_request() is called to emit the breadcrumb commands for the
request into the ring, name it such (engine->emit_breadcrumb).
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/20161028125858.23563-27-chris@chris-wilson.co.uk
Though we will have multiple timelines, we still have a single timeline
of execution. This we can use to provide an execution and retirement order
of requests. This keeps tracking execution of requests simple, and vital
for preserving a single waiter (i.e. so that we can order the waiters so
that only the earliest to wakeup need be woken). To accomplish this we
distinguish the seqno used to order requests per-context (external) and
that used internally for execution.
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/20161028125858.23563-26-chris@chris-wilson.co.uk
In future patches, we will no longer be able to wait on a static global
seqno and instead have to break our wait up into phases. First we wait
for the global seqno assignment (upon submission to hardware), and once
submitted we wait for the hardware to complete.
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/20161028125858.23563-25-chris@chris-wilson.co.uk
Before suspend, we wait for the switch to the kernel context. In order
for all the other context images to be complete upon suspend, that
switch must be the last operation by the GPU (i.e. this idling request
must not overtake any pending requests). To make this request execute last,
we make it depend on every other inflight request.
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/20161028125858.23563-24-chris@chris-wilson.co.uk
Our timelines are more than just a seqno. They also provide an ordered
list of requests to be executed. Due to the restriction of handling
individual address spaces, we are limited to a timeline per address
space but we use a fence context per engine within.
Our first step to introducing independent timelines per context (i.e. to
allow each context to have a queue of requests to execute that have a
defined set of dependencies on other requests) is to provide a timeline
abstraction for the global execution queue.
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/20161028125858.23563-23-chris@chris-wilson.co.uk
After combining the dma-buf reservation object and the GEM reservation
object, we lost the ability to do a nonblocking wait on the i915 request
(as we blocked upon the reservation object during prepare_fb). We can
instead convert the reservation object into a fence upon which we can
asynchronously wait (including a forced timeout in case the DMA fence is
never signaled).
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/20161028125858.23563-22-chris@chris-wilson.co.uk
In preparation to support many distinct timelines, we need to expand the
activity tracking on the GEM object to handle more than just a request
per engine. We already use the struct reservation_object on the dma-buf
to handle many fence contexts, so integrating that into the GEM object
itself is the preferred solution. (For example, we can now share the same
reservation_object between every consumer/producer using this buffer and
skip the manual import/export via dma-buf.)
v2: Reimplement busy-ioctl (by walking the reservation object), postpone
the ABI change for another day. Similarly use the reservation object to
find the last_write request (if active and from i915) for choosing
display CS flips.
Caveats:
* busy-ioctl: busy-ioctl only reports on the native fences, it will not
warn of stalls (in set-domain-ioctl, pread/pwrite etc) if the object is
being rendered to by external fences. It also will not report the same
busy state as wait-ioctl (or polling on the dma-buf) in the same
circumstances. On the plus side, it does retain reporting of which
*i915* engines are engaged with this object.
* non-blocking atomic modesets take a step backwards as the wait for
render completion blocks the ioctl. This is fixed in a subsequent
patch to use a fence instead for awaiting on the rendering, see
"drm/i915: Restore nonblocking awaits for modesetting"
* dynamic array manipulation for shared-fences in reservation is slower
than the previous lockless static assignment (e.g. gem_exec_lut_handle
runtime on ivb goes from 42s to 66s), mainly due to atomic operations
(maintaining the fence refcounts).
* loss of object-level retirement callbacks, emulated by VMA retirement
tracking.
* minor loss of object-level last activity information from debugfs,
could be replaced with per-vma information if desired
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/20161028125858.23563-21-chris@chris-wilson.co.uk
Having moved the locked phase of freeing an object to a separate worker,
we can now declare to the core that we only need the unlocked variant of
driver->gem_free_object, and can use the simple unreference internally.
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/20161028125858.23563-20-chris@chris-wilson.co.uk
We want to hide the latency of releasing objects and their backing
storage from the submission, so we move the actual free to a worker.
This allows us to switch to struct_mutex freeing of the object in the
next patch.
Furthermore, if we know that the object we are dereferencing remains valid
for the duration of our access, we can forgo the usual synchronisation
barriers and atomic reference counting. To ensure this we defer freeing
an object til after an RCU grace period, such that any lookup of the
object within an RCU read critical section will remain valid until
after we exit that critical section. We also employ this delay for
rate-limiting the serialisation on reallocation - we have to slow down
object creation in order to prevent resource starvation (in particular,
files).
v2: Return early in i915_gem_tiling() ioctl to skip over superfluous
work on error.
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/20161028125858.23563-19-chris@chris-wilson.co.uk
We only need struct_mutex within pwrite for a brief window where we need
to serialise with rendering and control our cache domains. Elsewhere we
can rely on the backing storage being pinned, and forgive userspace any
races against us.
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/20161028125858.23563-17-chris@chris-wilson.co.uk
We only need struct_mutex within pread for a brief window where we need
to serialise with rendering and control our cache domains. Elsewhere we
can rely on the backing storage being pinned, and forgive userspace any
races against us.
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/20161028125858.23563-16-chris@chris-wilson.co.uk
Break the allocation of the backing storage away from struct_mutex into
a per-object lock. This allows parallel page allocation, provided we can
do so outside of struct_mutex (i.e. set-domain-ioctl, pwrite, GTT
fault), i.e. before execbuf! The increased cost of the atomic counters
are hidden behind i915_vma_pin() for the typical case of execbuf, i.e.
as the object is typically bound between execbufs, the page_pin_count is
static. The cost will be felt around set-domain and pwrite, but offset
by the improvement from reduced struct_mutex contention.
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/20161028125858.23563-14-chris@chris-wilson.co.uk
