[Intel-gfx] [PATCH 02/12] drm/i915/gt: Cancel the flush worker more thoroughly

[Mika Kuoppala]

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

> Since the worker may rearm, we currently are only guaranteed to flush
> the work if we cancel the timer. If the work was running at the time we
> try and cancel it, we will wait for it to complete, but it may leave
> items in the pool and requeue the work. If we rearrange the immediate
> discard of the pool then cancel the work, we know that the work cannot
> rearm and so our flush will be final.
>
> <0> [314.146044] i915_mod-1321    2.... 299799443us : intel_gt_fini_buffer_pool: intel_gt_fini_buffer_pool:227 GEM_BUG_ON(!list_empty(&pool->cache_list[n]))
>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
> index 1495054a4305..418ae184cecf 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_buffer_pool.c
> @@ -212,8 +212,9 @@ void intel_gt_flush_buffer_pool(struct intel_gt *gt)
>  {
>  	struct intel_gt_buffer_pool *pool = &gt->buffer_pool;
>  
> -	if (cancel_delayed_work_sync(&pool->work))
> +	do {
>  		pool_free_imm(pool);
> +	} while (cancel_delayed_work_sync(&pool->work));

Yeah changing of order makes sense. If you want
a guarantee that the finit goes as you expect, you
could add two cancel_delayed_work_sync and assert
that the final one return false.

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

>  }
>  
>  void intel_gt_fini_buffer_pool(struct intel_gt *gt)
> -- 
> 2.20.1
>
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