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  1. 04 10月, 2019 2 次提交
  3. 28 9月, 2019 1 次提交
  5. 07 9月, 2019 1 次提交
  7. 09 8月, 2019 1 次提交
  9. 13 7月, 2019 1 次提交
  11. 21 6月, 2019 4 次提交
  13. 15 6月, 2019 1 次提交
    • C
      drm/i915: Keep contexts pinned until after the next kernel context switch · ce476c80
      由 Chris Wilson 提交于 
      We need to keep the context image pinned in memory until after the GPU
has finished writing into it. Since it continues to write as we signal
the final breadcrumb, we need to keep it pinned until the request after
it is complete. Currently we know the order in which requests execute on
each engine, and so to remove that presumption we need to identify a
request/context-switch we know must occur after our completion. Any
request queued after the signal must imply a context switch, for
simplicity we use a fresh request from the kernel context.

The sequence of operations for keeping the context pinned until saved is:

 - On context activation, we preallocate a node for each physical engine
   the context may operate on. This is to avoid allocations during
   unpinning, which may be from inside FS_RECLAIM context (aka the
   shrinker)

 - On context deactivation on retirement of the last active request (which
   is before we know the context has been saved), we add the
   preallocated node onto a barrier list on each engine

 - On engine idling, we emit a switch to kernel context. When this
   switch completes, we know that all previous contexts must have been
   saved, and so on retiring this request we can finally unpin all the
   contexts that were marked as deactivated prior to the switch.

We can enhance this in future by flushing all the idle contexts on a
regular heartbeat pulse of a switch to kernel context, which will also
be used to check for hung engines.

v2: intel_context_active_acquire/_release
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190614164606.15633-1-chris@chris-wilson.co.uk
      ce476c80
  15. 14 6月, 2019 3 次提交
  17. 12 6月, 2019 1 次提交
  19. 06 6月, 2019 1 次提交
  21. 28 5月, 2019 1 次提交
  23. 08 5月, 2019 2 次提交
  25. 27 4月, 2019 1 次提交
  27. 25 4月, 2019 3 次提交
  29. 21 3月, 2019 1 次提交
  31. 08 3月, 2019 1 次提交
  33. 06 3月, 2019 1 次提交
  35. 28 2月, 2019 2 次提交
  37. 09 2月, 2019 1 次提交
    • C
      drm/i915: Revoke mmaps and prevent access to fence registers across reset · 2caffbf1
      由 Chris Wilson 提交于 
      Previously, we were able to rely on the recursive properties of
struct_mutex to allow us to serialise revoking mmaps and reacquiring the
FENCE registers with them being clobbered over a global device reset.
I then proceeded to throw out the baby with the bath water in order to
pursue a struct_mutex-less reset.

Perusing LWN for alternative strategies, the dilemma on how to serialise
access to a global resource on one side was answered by
https://lwn.net/Articles/202847/ -- Sleepable RCU:

    1  int readside(void) {
    2      int idx;
    3      rcu_read_lock();
    4	   if (nomoresrcu) {
    5          rcu_read_unlock();
    6	       return -EINVAL;
    7      }
    8	   idx = srcu_read_lock(&ss);
    9	   rcu_read_unlock();
    10	   /* SRCU read-side critical section. */
    11	   srcu_read_unlock(&ss, idx);
    12	   return 0;
    13 }
    14
    15 void cleanup(void)
    16 {
    17     nomoresrcu = 1;
    18     synchronize_rcu();
    19     synchronize_srcu(&ss);
    20     cleanup_srcu_struct(&ss);
    21 }

No more worrying about stop_machine, just an uber-complex mutex,
optimised for reads, with the overhead pushed to the rare reset path.

However, we do run the risk of a deadlock as we allocate underneath the
SRCU read lock, and the allocation may require a GPU reset, causing a
dependency cycle via the in-flight requests. We resolve that by declaring
the driver wedged and cancelling all in-flight rendering.

v2: Use expedited rcu barriers to match our earlier timing
characteristics.
v3: Try to annotate locking contexts for sparse
v4: Reduce selftest lock duration to avoid a reset deadlock with fences
v5: s/srcu/reset_backoff_srcu/
v6: Remove more stale comments

Testcase: igt/gem_mmap_gtt/hang
Fixes: eb8d0f5a ("drm/i915: Remove GPU reset dependence on struct_mutex")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: NMika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190208153708.20023-2-chris@chris-wilson.co.uk
      2caffbf1
  39. 29 1月, 2019 1 次提交
  41. 25 1月, 2019 1 次提交
  43. 22 1月, 2019 1 次提交
  45. 16 1月, 2019 1 次提交
  47. 15 1月, 2019 1 次提交
  49. 08 1月, 2019 1 次提交
  51. 07 7月, 2018 1 次提交
  53. 24 5月, 2018 1 次提交
  55. 09 5月, 2018 1 次提交
  57. 04 5月, 2018 1 次提交
    • C
      drm/i915: Lazily unbind vma on close · 3365e226
      由 Chris Wilson 提交于 
      When userspace is passing around swapbuffers using DRI, we frequently
have to open and close the same object in the foreign address space.
This shows itself as the same object being rebound at roughly 30fps
(with a second object also being rebound at 30fps), which involves us
having to rewrite the page tables and maintain the drm_mm range manager
every time.

However, since the object still exists and it is only the local handle
that disappears, if we are lazy and do not unbind the VMA immediately
when the local user closes the object but defer it until the GPU is
idle, then we can reuse the same VMA binding. We still have to be
careful to mark the handle and lookup tables as closed to maintain the
uABI, just allowing the underlying VMA to be resurrected if the user is
able to access the same object from the same context again.

If the object itself is destroyed (neither userspace keeping a handle to
it), the VMA will be reaped immediately as usual.

In the future, this will be even more useful as instantiating a new VMA
for use on the GPU will become heavier. A nuisance indeed, so nip it in
the bud.

v2: s/__i915_vma_final_close/i915_vma_destroy/ etc.
v3: Leave a hint as to why we deferred the unbind on close.
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180503195115.22309-1-chris@chris-wilson.co.uk
      3365e226
  59. 03 5月, 2018 1 次提交