On 08/01/2016 22:08, Chris Wilson wrote:
On Fri, Jan 08, 2016 at 06:47:25PM +0000, John.C.Harrison@xxxxxxxxx wrote:
From: John Harrison <John.C.Harrison@xxxxxxxxx>
The request structure is reference counted. When the count reached
zero, the request was immediately freed and all associated objects
were unrefereced/unallocated. This meant that the driver mutex lock
must be held at the point where the count reaches zero. This was fine
while all references were held internally to the driver. However, the
plan is to allow the underlying fence object (and hence the request
itself) to be returned to other drivers and to userland. External
users cannot be expected to acquire a driver private mutex lock.
It's a trivial issue to fix to enable freeing requests without holding the
struct_mutex. You don't need to even add any new lists, delayed freeing
mechanisms and whotnot.
-Chris
As the driver stands, it is not trivial to free a request without
holding the mutex. It does things like unpinning buffers, freeing up
contexts (which is a whole other bundle of complication), releasing
IRQs. It may be possible to re-organise things to make those operations
safe to do without the mutex but it certainly does not look trivial!
_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
http://lists.freedesktop.org/mailman/listinfo/intel-gfx
