[Intel-gfx] [PATCH] drm/i915: Wake up all waiters before idling

Mika Kuoppala mika.kuoppala at linux.intel.com
Mon Mar 6 10:55:09 UTC 2017


Chris Wilson <chris at chris-wilson.co.uk> writes:

> When we idle, we wakeup the first waiter (checking to see if it missed
> an earlier wakeup) and disarm the breadcrumbs. However, we now assert
> that there are no waiter when the interrupt is disabled, triggering an
> assert if there were multiple waiters when we idled.
>
> [  420.842275] invalid opcode: 0000 [#1] PREEMPT SMP
> [  420.842285] Modules linked in: vgem snd_hda_codec_realtek x86_pkg_temp_thermal snd_hda_codec_generic intel_powerclamp coretemp crct10dif_pclmul crc32_pclmul ghash_clmulni_intel snd_hda_intel snd_hda_codec snd_hwdep mei_me snd_hda_core mei snd_pcm lpc_ich i915 r8169 mii prime_numbers
> [  420.842357] CPU: 4 PID: 8714 Comm: kms_pipe_crc_ba Tainted: G     U  W       4.10.0-CI-CI_DRM_2280+ #1
> [  420.842377] Hardware name: Hewlett-Packard HP Pro 3500 Series/2ABF, BIOS 8.11 10/24/2012
> [  420.842395] task: ffff880117ddce40 task.stack: ffffc90001114000
> [  420.842439] RIP: 0010:__intel_engine_remove_wait+0x1f4/0x200 [i915]
> [  420.842454] RSP: 0018:ffffc90001117b18 EFLAGS: 00010046
> [  420.842467] RAX: 0000000000000000 RBX: ffff88010c25c2a8 RCX: 0000000000000001
> [  420.842481] RDX: 0000000000000001 RSI: 00000000ffffffff RDI: ffffc90001117c50
> [  420.842495] RBP: ffffc90001117b58 R08: 0000000011e52352 R09: c4d16acc00000000
> [  420.842511] R10: ffffffff82789eb0 R11: ffff880117ddce40 R12: ffffc90001117c50
> [  420.842525] R13: ffffc90001117c50 R14: 0000000000000078 R15: 0000000000000000
> [  420.842540] FS:  00007fe47dda0a40(0000) GS:ffff88011fb00000(0000) knlGS:0000000000000000
> [  420.842559] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  420.842571] CR2: 00007fd6c0a2cec4 CR3: 000000010a5e5000 CR4: 00000000001406e0
> [  420.842586] Call Trace:
> [  420.842595]  ? do_raw_spin_lock+0xad/0xb0
> [  420.842635]  intel_engine_remove_wait.part.3+0x26/0x40 [i915]
> [  420.842678]  intel_engine_remove_wait+0xe/0x20 [i915]
> [  420.842721]  i915_wait_request+0x4f0/0x8c0 [i915]
> [  420.842736]  ? wake_up_q+0x70/0x70
> [  420.842747]  ? wake_up_q+0x70/0x70
> [  420.842787]  i915_gem_object_wait_fence+0x7d/0x1a0 [i915]
> [  420.842829]  i915_gem_object_wait+0x30d/0x520 [i915]
> [  420.842842]  ? __this_cpu_preempt_check+0x13/0x20
> [  420.842884]  i915_gem_wait_ioctl+0x12e/0x2e0 [i915]
> [  420.842924]  ? i915_gem_wait_ioctl+0x22/0x2e0 [i915]
> [  420.842939]  drm_ioctl+0x200/0x450
> [  420.842976]  ? i915_gem_set_wedged+0x90/0x90 [i915]
> [  420.842993]  do_vfs_ioctl+0x90/0x6e0
> [  420.843003]  ? entry_SYSCALL_64_fastpath+0x5/0xb1
> [  420.843017]  ? __this_cpu_preempt_check+0x13/0x20
> [  420.843030]  ? trace_hardirqs_on_caller+0xe7/0x200
> [  420.843042]  SyS_ioctl+0x3c/0x70
> [  420.843054]  entry_SYSCALL_64_fastpath+0x1c/0xb1
> [  420.843065] RIP: 0033:0x7fe47c4b9357
> [  420.843075] RSP: 002b:00007ffc3c0633c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> [  420.843094] RAX: ffffffffffffffda RBX: ffffffff81482393 RCX: 00007fe47c4b9357
> [  420.843109] RDX: 00007ffc3c063400 RSI: 00000000c010646c RDI: 0000000000000004
> [  420.843123] RBP: ffffc90001117f88 R08: 0000000000000008 R09: 0000000000000000
> [  420.843137] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> [  420.843151] R13: 0000000000000004 R14: 00000000c010646c R15: 0000000000000000
> [  420.843168]  ? __this_cpu_preempt_check+0x13/0x20
> [  420.843180] Code: 81 48 c7 c1 40 6a 16 a0 48 c7 c2 47 29 15 a0 be 17 01 00 00 48 c7 c7 10 6a 16 a0 e8 c7 ea fe e0 e9 5d ff ff ff 0f 0b 0f 0b 0f 0b <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 e8 67 41 7e e1
> [  420.843325] RIP: __intel_engine_remove_wait+0x1f4/0x200 [i915] RSP: ffffc90001117b18
>
> Fixes: b66255f0f779 ("drm/i915: Refactor wakeup of the next breadcrumb waiter")
> Fixes: 67b807a89230 ("drm/i915: Delay disabling the user interrupt for breadcrumbs")
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Reviewed-by: Mika Kuoppala <mika.kuoppala at intel.com>

> Cc: Mika Kuoppala <mika.kuoppala at intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_breadcrumbs.c | 19 +++++++++++++------
>  1 file changed, 13 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_breadcrumbs.c b/drivers/gpu/drm/i915/intel_breadcrumbs.c
> index 6032d2a937d5..105e463bb7e6 100644
> --- a/drivers/gpu/drm/i915/intel_breadcrumbs.c
> +++ b/drivers/gpu/drm/i915/intel_breadcrumbs.c
> @@ -167,6 +167,7 @@ void __intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine)
>  	struct intel_breadcrumbs *b = &engine->breadcrumbs;
>  
>  	lockdep_assert_held(&b->irq_lock);
> +	GEM_BUG_ON(b->irq_wait);
>  
>  	if (b->irq_enabled) {
>  		irq_disable(engine);
> @@ -179,23 +180,29 @@ void __intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine)
>  void intel_engine_disarm_breadcrumbs(struct intel_engine_cs *engine)
>  {
>  	struct intel_breadcrumbs *b = &engine->breadcrumbs;
> -	unsigned long flags;
> +	struct intel_wait *wait, *n;
>  
>  	if (!b->irq_armed)
>  		return;
>  
> -	spin_lock_irqsave(&b->irq_lock, flags);
> -
>  	/* We only disarm the irq when we are idle (all requests completed),
>  	 * so if there remains a sleeping waiter, it missed the request
>  	 * completion.
>  	 */
> -	if (__intel_breadcrumbs_wakeup(b) & ENGINE_WAKEUP_ASLEEP)
> -		missed_breadcrumb(engine);
>  
> +	spin_lock_irq(&b->rb_lock);
> +	rbtree_postorder_for_each_entry_safe(wait, n, &b->waiters, node) {
> +		RB_CLEAR_NODE(&wait->node);
> +		if (wake_up_process(wait->tsk) && wait == b->irq_wait)
> +			missed_breadcrumb(engine);
> +	}
> +
> +	spin_lock(&b->irq_lock);
> +	b->irq_wait = NULL;
>  	__intel_engine_disarm_breadcrumbs(engine);
> +	spin_unlock(&b->irq_lock);
>  
> -	spin_unlock_irqrestore(&b->irq_lock, flags);
> +	spin_unlock_irq(&b->rb_lock);
>  }
>  
>  static bool use_fake_irq(const struct intel_breadcrumbs *b)
> -- 
> 2.11.0


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