[Intel-gfx] [PATCH] drm/i915: Drop stealing of bits from i915_sw_fence function pointer
Tvrtko Ursulin
tvrtko.ursulin at linux.intel.com
Wed Sep 22 15:25:04 UTC 2021
On 22/09/2021 16:21, Tvrtko Ursulin wrote:
>
> On 22/09/2021 15:57, Matthew Brost wrote:
>> Rather than stealing bits from i915_sw_fence function pointer use
>> seperate fields for function pointer and flags. If using two different
>> fields, the 4 byte alignment for the i915_sw_fence function pointer can
>> also be dropped.
>>
>> v2:
>> (CI)
>> - Set new function field rather than flags in __i915_sw_fence_init
>>
>> Signed-off-by: Matthew Brost <matthew.brost at intel.com>
>> ---
>> drivers/gpu/drm/i915/display/intel_display.c | 2 +-
>> drivers/gpu/drm/i915/gem/i915_gem_context.c | 2 +-
>> drivers/gpu/drm/i915/i915_request.c | 4 ++--
>> drivers/gpu/drm/i915/i915_sw_fence.c | 12 +++++------
>> drivers/gpu/drm/i915/i915_sw_fence.h | 21 +++++++++----------
>> drivers/gpu/drm/i915/i915_sw_fence_work.c | 2 +-
>> .../gpu/drm/i915/selftests/i915_sw_fence.c | 2 +-
>> drivers/gpu/drm/i915/selftests/lib_sw_fence.c | 4 ++--
>> 8 files changed, 23 insertions(+), 26 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c
>> b/drivers/gpu/drm/i915/display/intel_display.c
>> index a7ca38613f89..6d5bb55ffc82 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display.c
>> +++ b/drivers/gpu/drm/i915/display/intel_display.c
>> @@ -10323,7 +10323,7 @@ static void intel_atomic_commit_work(struct
>> work_struct *work)
>> intel_atomic_commit_tail(state);
>> }
>> -static int __i915_sw_fence_call
>> +static int
>> intel_atomic_commit_ready(struct i915_sw_fence *fence,
>> enum i915_sw_fence_notify notify)
>> {
>> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_context.c
>> b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>> index c2ab0e22db0a..df5fec5c3da8 100644
>> --- a/drivers/gpu/drm/i915/gem/i915_gem_context.c
>> +++ b/drivers/gpu/drm/i915/gem/i915_gem_context.c
>> @@ -800,7 +800,7 @@ static void free_engines_rcu(struct rcu_head *rcu)
>> free_engines(engines);
>> }
>> -static int __i915_sw_fence_call
>> +static int
>> engines_notify(struct i915_sw_fence *fence, enum
>> i915_sw_fence_notify state)
>> {
>> struct i915_gem_engines *engines =
>> diff --git a/drivers/gpu/drm/i915/i915_request.c
>> b/drivers/gpu/drm/i915/i915_request.c
>> index ce446716d092..945d3025a0b6 100644
>> --- a/drivers/gpu/drm/i915/i915_request.c
>> +++ b/drivers/gpu/drm/i915/i915_request.c
>> @@ -719,7 +719,7 @@ void i915_request_cancel(struct i915_request *rq,
>> int error)
>> intel_context_cancel_request(rq->context, rq);
>> }
>> -static int __i915_sw_fence_call
>> +static int
>> submit_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify
>> state)
>> {
>> struct i915_request *request =
>> @@ -755,7 +755,7 @@ submit_notify(struct i915_sw_fence *fence, enum
>> i915_sw_fence_notify state)
>> return NOTIFY_DONE;
>> }
>> -static int __i915_sw_fence_call
>> +static int
>> semaphore_notify(struct i915_sw_fence *fence, enum
>> i915_sw_fence_notify state)
>> {
>> struct i915_request *rq = container_of(fence, typeof(*rq),
>> semaphore);
>> diff --git a/drivers/gpu/drm/i915/i915_sw_fence.c
>> b/drivers/gpu/drm/i915/i915_sw_fence.c
>> index c589a681da77..1c080dd1f718 100644
>> --- a/drivers/gpu/drm/i915/i915_sw_fence.c
>> +++ b/drivers/gpu/drm/i915/i915_sw_fence.c
>> @@ -34,7 +34,7 @@ enum {
>> static void *i915_sw_fence_debug_hint(void *addr)
>> {
>> - return (void *)(((struct i915_sw_fence *)addr)->flags &
>> I915_SW_FENCE_MASK);
>> + return (void *)(((struct i915_sw_fence *)addr)->fn);
>> }
>> #ifdef CONFIG_DRM_I915_SW_FENCE_DEBUG_OBJECTS
>> @@ -126,10 +126,7 @@ static inline void debug_fence_assert(struct
>> i915_sw_fence *fence)
>> static int __i915_sw_fence_notify(struct i915_sw_fence *fence,
>> enum i915_sw_fence_notify state)
>> {
>> - i915_sw_fence_notify_t fn;
>> -
>> - fn = (i915_sw_fence_notify_t)(fence->flags & I915_SW_FENCE_MASK);
>> - return fn(fence, state);
>> + return fence->fn(fence, state);
>> }
>> #ifdef CONFIG_DRM_I915_SW_FENCE_DEBUG_OBJECTS
>> @@ -242,10 +239,11 @@ void __i915_sw_fence_init(struct i915_sw_fence
>> *fence,
>> const char *name,
>> struct lock_class_key *key)
>> {
>> - BUG_ON(!fn || (unsigned long)fn & ~I915_SW_FENCE_MASK);
>> + BUG_ON(!fn);
>> __init_waitqueue_head(&fence->wait, name, key);
>> - fence->flags = (unsigned long)fn;
>> + fence->fn = fn;
>> + fence->flags = 0;
>> i915_sw_fence_reinit(fence);
>> }
>> diff --git a/drivers/gpu/drm/i915/i915_sw_fence.h
>> b/drivers/gpu/drm/i915/i915_sw_fence.h
>> index 30a863353ee6..70ba1789aa89 100644
>> --- a/drivers/gpu/drm/i915/i915_sw_fence.h
>> +++ b/drivers/gpu/drm/i915/i915_sw_fence.h
>> @@ -17,26 +17,25 @@
>> struct completion;
>> struct dma_resv;
>> +struct i915_sw_fence;
>> +
>> +enum i915_sw_fence_notify {
>> + FENCE_COMPLETE,
>> + FENCE_FREE
>> +};
>> +
>> +typedef int (*i915_sw_fence_notify_t)(struct i915_sw_fence *,
>> + enum i915_sw_fence_notify state);
>> struct i915_sw_fence {
>> wait_queue_head_t wait;
>> + i915_sw_fence_notify_t fn;
>> unsigned long flags;
>
> Looks good to me. I'd just make the flags narrower now that they can be,
> and put them down..
>
>> atomic_t pending;
>
> .. here as unsigned int and so we save 4 bytes, maybe.
No this won't work due test_and_set_bit needs a long, oh well.
>
> In fact, unless CONFIG_DRM_I915_SW_FENCE_CHECK_DAG is on, which it won't
> be on release builds, I don't think anything uses flags any more. So you
> could even omit the flags in that case. Might be cumbersome so can leave
> for later, but would sure be nice not to waste space if we can avoid it.
>
> Also please double check if i915_sw_fence_reinit() will be fine and
> won't bug on since fence->flags is always zero now I think.
But these two are worth checking out.
Regards,
Tvrtko
>
> Regards,
>
> Tvrtko
>
>> int error;
>> };
>> #define I915_SW_FENCE_CHECKED_BIT 0 /* used internally for DAG
>> checking */
>> -#define I915_SW_FENCE_PRIVATE_BIT 1 /* available for use by owner */
>> -#define I915_SW_FENCE_MASK (~3)
>> -
>> -enum i915_sw_fence_notify {
>> - FENCE_COMPLETE,
>> - FENCE_FREE
>> -};
>> -
>> -typedef int (*i915_sw_fence_notify_t)(struct i915_sw_fence *,
>> - enum i915_sw_fence_notify state);
>> -#define __i915_sw_fence_call __aligned(4)
>> void __i915_sw_fence_init(struct i915_sw_fence *fence,
>> i915_sw_fence_notify_t fn,
>> diff --git a/drivers/gpu/drm/i915/i915_sw_fence_work.c
>> b/drivers/gpu/drm/i915/i915_sw_fence_work.c
>> index 5b33ef23d54c..d2e56b387993 100644
>> --- a/drivers/gpu/drm/i915/i915_sw_fence_work.c
>> +++ b/drivers/gpu/drm/i915/i915_sw_fence_work.c
>> @@ -23,7 +23,7 @@ static void fence_work(struct work_struct *work)
>> dma_fence_put(&f->dma);
>> }
>> -static int __i915_sw_fence_call
>> +static int
>> fence_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify
>> state)
>> {
>> struct dma_fence_work *f = container_of(fence, typeof(*f), chain);
>> diff --git a/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
>> b/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
>> index cbf45d85cbff..daa985e5a19b 100644
>> --- a/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
>> +++ b/drivers/gpu/drm/i915/selftests/i915_sw_fence.c
>> @@ -28,7 +28,7 @@
>> #include "../i915_selftest.h"
>> -static int __i915_sw_fence_call
>> +static int
>> fence_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify
>> state)
>> {
>> switch (state) {
>> diff --git a/drivers/gpu/drm/i915/selftests/lib_sw_fence.c
>> b/drivers/gpu/drm/i915/selftests/lib_sw_fence.c
>> index 080b90b63d16..eb59a41bdb79 100644
>> --- a/drivers/gpu/drm/i915/selftests/lib_sw_fence.c
>> +++ b/drivers/gpu/drm/i915/selftests/lib_sw_fence.c
>> @@ -26,7 +26,7 @@
>> /* Small library of different fence types useful for writing tests */
>> -static int __i915_sw_fence_call
>> +static int
>> nop_fence_notify(struct i915_sw_fence *fence, enum
>> i915_sw_fence_notify state)
>> {
>> return NOTIFY_DONE;
>> @@ -89,7 +89,7 @@ struct heap_fence {
>> };
>> };
>> -static int __i915_sw_fence_call
>> +static int
>> heap_fence_notify(struct i915_sw_fence *fence, enum
>> i915_sw_fence_notify state)
>> {
>> struct heap_fence *h = container_of(fence, typeof(*h), fence);
>>
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