On 07/10/2016 17:22, Chris Wilson wrote:
On Fri, Oct 07, 2016 at 05:10:04PM +0100, Tvrtko Ursulin wrote:
On 07/10/2016 10:46, Chris Wilson wrote:
In forthcoming patches, we want to be able to dynamically allocate the
wait_queue_t used whilst awaiting. This is more convenient if we extend
the i915_sw_fence_await_sw_fence() to perform the allocation for us if
we pass in a gfp mask as an alternative than a preallocated struct.
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahti...@linux.intel.com>
---
drivers/gpu/drm/i915/i915_sw_fence.c | 40 ++++++++++++++++++++++++++++++++----
drivers/gpu/drm/i915/i915_sw_fence.h | 8 ++++++++
2 files changed, 44 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c
b/drivers/gpu/drm/i915/i915_sw_fence.c
index 1e5cbc585ca2..dfb59dced0ce 100644
--- a/drivers/gpu/drm/i915/i915_sw_fence.c
+++ b/drivers/gpu/drm/i915/i915_sw_fence.c
@@ -13,6 +13,8 @@
#include "i915_sw_fence.h"
+#define I915_SW_FENCE_FLAG_ALLOC BIT(0)
+
You collide with WQ_FLAG_EXCLUSIVE here, so I assume i915 will have
complete control of the wq in question?
Hmm, we should move bit as well, but yes the flag is atm private to the
wake up function for which we use a custom function.
+ wq = kmalloc(sizeof(*wq), gfp);
+ if (!wq) {
+ if (!gfpflags_allow_blocking(gfp))
+ return -ENOMEM;
+
+ i915_sw_fence_wait(signaler);
This looks like a strange API, unless I am missing something - it
normally sets things up for waiting, unless the allocation fails
when it actually does the wait?
Yes. If we blocked on the malloc and failed, we block a little more for
the completion. iirc, the idea came from the async task.
Still sounds strange to me. I understand it is a unlikely corner case
but sounds like that sort of decision should happen in the caller. I
will have to revisit the i915_sw_fence implementation and usage in more
detail it seems.
Regards,
Tvrtko
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