[Intel-gfx] [PATCH 08/15] drm/i915: Slaughter the thundering i915_wait_request herd

[Dave Gordon]

On 30/11/15 14:18, Chris Wilson wrote:
> On Mon, Nov 30, 2015 at 01:32:16PM +0000, Tvrtko Ursulin wrote:
>>
>> On 30/11/15 12:30, Chris Wilson wrote:
>>> On Mon, Nov 30, 2015 at 12:05:50PM +0000, Tvrtko Ursulin wrote:
>>>>> +	struct intel_breadcrumbs {
>>>>> +		spinlock_t lock; /* protects the per-engine request list */
>>>>
>>>> s/list/tree/
>>>
>>> list. We use the tree as a list!
>>
>> Maybe but it confuses the reader a bit who goes and looks for some
>> list then.
>>
>> Related, when I was playing with this I was piggy backing on the
>> existing per engine request list.
>
> A separate list with separate locking only used when waiting, that's the
> appeal for me.

The patchset recently posted by John Harrison
"[RFC 00/12] Convert requests to use struct fence"
provides exactly that. No struct_mutex involved,
and only the relevant waiters get woken up.

.Dave.