Commit Graph

4 Commits

Author SHA1 Message Date
Maarten Lankhorst 47b086934f drm/i915: Make sure execbuffer always passes ww state to i915_vma_pin.
As a preparation step for full object locking and wait/wound handling
during pin and object mapping, ensure that we always pass the ww context
in i915_gem_execbuffer.c to i915_vma_pin, use lockdep to ensure this
happens.

This also requires changing the order of eb_parse slightly, to ensure
we pass ww at a point where we could still handle -EDEADLK safely.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Thomas Hellström <thomas.hellstrom@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200819140904.1708856-15-maarten.lankhorst@linux.intel.com
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
2020-09-07 14:31:13 +03:00
Chris Wilson 32a55a109f drm/i915/gt: Mark up racy read of intel_ring.head
The intel_ring.head is updated as the requests are retired, but is
sampled at any time as we submit requests. Furthermore, it tracks
RING_HEAD which is inherently asynchronous.

[  148.630314] BUG: KCSAN: data-race in execlists_dequeue [i915] / i915_request_retire [i915]
[  148.630349]
[  148.630374] write to 0xffff8881f4e28ddc of 4 bytes by task 90 on cpu 2:
[  148.630752]  i915_request_retire+0xed/0x770 [i915]
[  148.631123]  retire_requests+0x7a/0xd0 [i915]
[  148.631491]  engine_retire+0xa6/0xe0 [i915]
[  148.631523]  process_one_work+0x3af/0x640
[  148.631552]  worker_thread+0x80/0x670
[  148.631581]  kthread+0x19a/0x1e0
[  148.631609]  ret_from_fork+0x1f/0x30
[  148.631629]
[  148.631652] read to 0xffff8881f4e28ddc of 4 bytes by task 14288 on cpu 3:
[  148.632019]  execlists_dequeue+0x1300/0x1680 [i915]
[  148.632384]  __execlists_submission_tasklet+0x48/0x60 [i915]
[  148.632770]  execlists_submit_request+0x38e/0x3c0 [i915]
[  148.633146]  submit_notify+0x8f/0xc0 [i915]
[  148.633512]  __i915_sw_fence_complete+0x5d/0x3e0 [i915]
[  148.633875]  i915_sw_fence_complete+0x58/0x80 [i915]
[  148.634238]  i915_sw_fence_commit+0x16/0x20 [i915]
[  148.634613]  __i915_request_queue+0x60/0x70 [i915]
[  148.634985]  i915_gem_do_execbuffer+0x2de0/0x42b0 [i915]
[  148.635366]  i915_gem_execbuffer2_ioctl+0x2ab/0x580 [i915]
[  148.635400]  drm_ioctl_kernel+0xe9/0x130
[  148.635429]  drm_ioctl+0x27d/0x45e
[  148.635456]  ksys_ioctl+0x89/0xb0
[  148.635482]  __x64_sys_ioctl+0x42/0x60
[  148.635510]  do_syscall_64+0x6e/0x2c0
[  148.635542]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

[  645.071436] BUG: KCSAN: data-race in gen8_emit_fini_breadcrumb [i915] / i915_request_retire [i915]
[  645.071456]
[  645.071467] write to 0xffff8881efe403dc of 4 bytes by task 14668 on cpu 3:
[  645.071647]  i915_request_retire+0xed/0x770 [i915]
[  645.071824]  i915_request_create+0x6c/0x160 [i915]
[  645.072000]  i915_gem_do_execbuffer+0x206d/0x42b0 [i915]
[  645.072177]  i915_gem_execbuffer2_ioctl+0x2ab/0x580 [i915]
[  645.072194]  drm_ioctl_kernel+0xe9/0x130
[  645.072208]  drm_ioctl+0x27d/0x45e
[  645.072222]  ksys_ioctl+0x89/0xb0
[  645.072235]  __x64_sys_ioctl+0x42/0x60
[  645.072248]  do_syscall_64+0x6e/0x2c0
[  645.072263]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  645.072275]
[  645.072285] read to 0xffff8881efe403dc of 4 bytes by interrupt on cpu 2:
[  645.072458]  gen8_emit_fini_breadcrumb+0x158/0x300 [i915]
[  645.072636]  __i915_request_submit+0x204/0x430 [i915]
[  645.072809]  execlists_dequeue+0x8e1/0x1680 [i915]
[  645.072982]  __execlists_submission_tasklet+0x48/0x60 [i915]
[  645.073154]  execlists_submit_request+0x38e/0x3c0 [i915]
[  645.073330]  submit_notify+0x8f/0xc0 [i915]
[  645.073499]  __i915_sw_fence_complete+0x5d/0x3e0 [i915]
[  645.073668]  i915_sw_fence_wake+0xc2/0x130 [i915]
[  645.073836]  __i915_sw_fence_complete+0x2cf/0x3e0 [i915]
[  645.074006]  i915_sw_fence_complete+0x58/0x80 [i915]
[  645.074175]  dma_i915_sw_fence_wake+0x3e/0x80 [i915]
[  645.074344]  signal_irq_work+0x62f/0x710 [i915]
[  645.074360]  irq_work_run_list+0xd7/0x110
[  645.074373]  irq_work_run+0x1d/0x50
[  645.074386]  smp_irq_work_interrupt+0x21/0x30
[  645.074400]  irq_work_interrupt+0xf/0x20
[  645.074414]  _raw_spin_unlock_irqrestore+0x34/0x40
[  645.074585]  execlists_submission_tasklet+0xde/0x170 [i915]
[  645.074602]  tasklet_action_common.isra.0+0x42/0x90
[  645.074617]  __do_softirq+0xc8/0x206
[  645.074629]  irq_exit+0xcd/0xe0
[  645.074642]  do_IRQ+0x44/0xc0
[  645.074654]  ret_from_intr+0x0/0x1c
[  645.074667]  finish_task_switch+0x73/0x230
[  645.074679]  __schedule+0x1c5/0x4c0
[  645.074691]  schedule+0x45/0xb0
[  645.074704]  worker_thread+0x194/0x670
[  645.074716]  kthread+0x19a/0x1e0
[  645.074729]  ret_from_fork+0x1f/0x30

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/20200407221832.15465-1-chris@chris-wilson.co.uk
2020-04-08 13:40:07 +01:00
Chris Wilson 5ba32c7be8 drm/i915/execlists: Always force a context reload when rewinding RING_TAIL
If we rewind the RING_TAIL on a context, due to a preemption event, we
must force the context restore for the RING_TAIL update to be properly
handled. Rather than note which preemption events may cause us to rewind
the tail, compare the new request's tail with the previously submitted
RING_TAIL, as it turns out that timeslicing was causing unexpected
rewinds.

   <idle>-0       0d.s2 1280851190us : __execlists_submission_tasklet: 0000:00:02.0 rcs0: expired last=130:4698, prio=3, hint=3
   <idle>-0       0d.s2 1280851192us : __i915_request_unsubmit: 0000:00:02.0 rcs0: fence 66:119966, current 119964
   <idle>-0       0d.s2 1280851195us : __i915_request_unsubmit: 0000:00:02.0 rcs0: fence 130:4698, current 4695
   <idle>-0       0d.s2 1280851198us : __i915_request_unsubmit: 0000:00:02.0 rcs0: fence 130:4696, current 4695
^----  Note we unwind 2 requests from the same context

   <idle>-0       0d.s2 1280851208us : __i915_request_submit: 0000:00:02.0 rcs0: fence 130:4696, current 4695
   <idle>-0       0d.s2 1280851213us : __i915_request_submit: 0000:00:02.0 rcs0: fence 134:1508, current 1506
^---- But to apply the new timeslice, we have to replay the first request
      before the new client can start -- the unexpected RING_TAIL rewind

   <idle>-0       0d.s2 1280851219us : trace_ports: 0000:00:02.0 rcs0: submit { 130:4696*, 134:1508 }
 synmark2-5425    2..s. 1280851239us : process_csb: 0000:00:02.0 rcs0: cs-irq head=5, tail=0
 synmark2-5425    2..s. 1280851240us : process_csb: 0000:00:02.0 rcs0: csb[0]: status=0x00008002:0x00000000
^---- Preemption event for the ELSP update; note the lite-restore

 synmark2-5425    2..s. 1280851243us : trace_ports: 0000:00:02.0 rcs0: preempted { 130:4698, 66:119966 }
 synmark2-5425    2..s. 1280851246us : trace_ports: 0000:00:02.0 rcs0: promote { 130:4696*, 134:1508 }
 synmark2-5425    2.... 1280851462us : __i915_request_commit: 0000:00:02.0 rcs0: fence 130:4700, current 4695
 synmark2-5425    2.... 1280852111us : __i915_request_commit: 0000:00:02.0 rcs0: fence 130:4702, current 4695
 synmark2-5425    2.Ns1 1280852296us : process_csb: 0000:00:02.0 rcs0: cs-irq head=0, tail=2
 synmark2-5425    2.Ns1 1280852297us : process_csb: 0000:00:02.0 rcs0: csb[1]: status=0x00000814:0x00000000
 synmark2-5425    2.Ns1 1280852299us : trace_ports: 0000:00:02.0 rcs0: completed { 130:4696!, 134:1508 }
 synmark2-5425    2.Ns1 1280852301us : process_csb: 0000:00:02.0 rcs0: csb[2]: status=0x00000818:0x00000040
 synmark2-5425    2.Ns1 1280852302us : trace_ports: 0000:00:02.0 rcs0: completed { 134:1508, 0:0 }
 synmark2-5425    2.Ns1 1280852313us : process_csb: process_csb:2336 GEM_BUG_ON(!i915_request_completed(*execlists->active) && !reset_in_progress(execlists))

Fixes: 8ee36e048c ("drm/i915/execlists: Minimalistic timeslicing")
Referenecs: 82c69bf586 ("drm/i915/gt: Detect if we miss WaIdleLiteRestore")
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>
Cc: <stable@vger.kernel.org> # v5.4+
Link: https://patchwork.freedesktop.org/patch/msgid/20200207211452.2860634-1-chris@chris-wilson.co.uk
2020-02-07 21:41:46 +00:00
Chris Wilson 2871ea85c1 drm/i915/gt: Split intel_ring_submission
Split the legacy submission backend from the common CS ring buffer
handling.

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/20191024100344.5041-1-chris@chris-wilson.co.uk
2019-10-24 12:14:21 +01:00