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[v4,03/12] drm/i915: Introduce a ww transaction helper

Message ID 20210615131451.61023-4-thomas.hellstrom@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series i915 TTM sync accelerated migration and clear | expand

Commit Message

Thomas Hellström June 15, 2021, 1:14 p.m. UTC
Introduce a for_i915_gem_ww(){} utility to help make the code
around a ww transaction more readable.

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
---
 drivers/gpu/drm/i915/i915_gem_ww.h | 31 +++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

Comments

Maarten Lankhorst June 16, 2021, 11 a.m. UTC | #1
Op 15-06-2021 om 15:14 schreef Thomas Hellström:
> Introduce a for_i915_gem_ww(){} utility to help make the code
> around a ww transaction more readable.
>
> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_gem_ww.h | 31 +++++++++++++++++++++++++++++-
>  1 file changed, 30 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_ww.h b/drivers/gpu/drm/i915/i915_gem_ww.h
> index f2d8769e4118..f6b1a796667b 100644
> --- a/drivers/gpu/drm/i915/i915_gem_ww.h
> +++ b/drivers/gpu/drm/i915/i915_gem_ww.h
> @@ -11,11 +11,40 @@ struct i915_gem_ww_ctx {
>  	struct ww_acquire_ctx ctx;
>  	struct list_head obj_list;
>  	struct drm_i915_gem_object *contended;
> -	bool intr;
> +	unsigned short intr;
> +	unsigned short loop;
>  };
>  
>  void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ctx, bool intr);
>  void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ctx);
>  int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ctx);
>  void i915_gem_ww_unlock_single(struct drm_i915_gem_object *obj);
> +
> +/* Internal functions used by the inlines! Don't use. */
> +static inline int __i915_gem_ww_fini(struct i915_gem_ww_ctx *ww, int err)
> +{
> +	ww->loop = 0;
> +	if (err == -EDEADLK) {
> +		err = i915_gem_ww_ctx_backoff(ww);
> +		if (!err)
> +			ww->loop = 1;
> +	}
> +
> +	if (!ww->loop)
> +		i915_gem_ww_ctx_fini(ww);
> +
> +	return err;
> +}
> +
> +static inline void
> +__i915_gem_ww_init(struct i915_gem_ww_ctx *ww, bool intr)
> +{
> +	i915_gem_ww_ctx_init(ww, intr);
> +	ww->loop = 1;
> +}
> +
> +#define for_i915_gem_ww(_ww, _err, _intr)			\
> +	for (__i915_gem_ww_init(_ww, _intr); (_ww)->loop;	\
> +	     _err = __i915_gem_ww_fini(_ww, _err))
> +
>  #endif

With some more macro abuse, we should be able to kill off ww->loop,

for (err = ({i915_gem_ww_ctx_init(ww, intr), -EDEADLK}); err == -EDEADLK; err = (err == -EDEADLK && !(err = i915_gem_ww_ctx_backoff(ww))) ? -EDEADLK : err)
Thomas Hellström June 16, 2021, 11:21 a.m. UTC | #2
On 6/16/21 1:00 PM, Maarten Lankhorst wrote:
> Op 15-06-2021 om 15:14 schreef Thomas Hellström:
>> Introduce a for_i915_gem_ww(){} utility to help make the code
>> around a ww transaction more readable.
>>
>> Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
>> Reviewed-by: Matthew Auld <matthew.auld@intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_gem_ww.h | 31 +++++++++++++++++++++++++++++-
>>   1 file changed, 30 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_gem_ww.h b/drivers/gpu/drm/i915/i915_gem_ww.h
>> index f2d8769e4118..f6b1a796667b 100644
>> --- a/drivers/gpu/drm/i915/i915_gem_ww.h
>> +++ b/drivers/gpu/drm/i915/i915_gem_ww.h
>> @@ -11,11 +11,40 @@ struct i915_gem_ww_ctx {
>>   	struct ww_acquire_ctx ctx;
>>   	struct list_head obj_list;
>>   	struct drm_i915_gem_object *contended;
>> -	bool intr;
>> +	unsigned short intr;
>> +	unsigned short loop;
>>   };
>>   
>>   void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ctx, bool intr);
>>   void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ctx);
>>   int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ctx);
>>   void i915_gem_ww_unlock_single(struct drm_i915_gem_object *obj);
>> +
>> +/* Internal functions used by the inlines! Don't use. */
>> +static inline int __i915_gem_ww_fini(struct i915_gem_ww_ctx *ww, int err)
>> +{
>> +	ww->loop = 0;
>> +	if (err == -EDEADLK) {
>> +		err = i915_gem_ww_ctx_backoff(ww);
>> +		if (!err)
>> +			ww->loop = 1;
>> +	}
>> +
>> +	if (!ww->loop)
>> +		i915_gem_ww_ctx_fini(ww);
>> +
>> +	return err;
>> +}
>> +
>> +static inline void
>> +__i915_gem_ww_init(struct i915_gem_ww_ctx *ww, bool intr)
>> +{
>> +	i915_gem_ww_ctx_init(ww, intr);
>> +	ww->loop = 1;
>> +}
>> +
>> +#define for_i915_gem_ww(_ww, _err, _intr)			\
>> +	for (__i915_gem_ww_init(_ww, _intr); (_ww)->loop;	\
>> +	     _err = __i915_gem_ww_fini(_ww, _err))
>> +
>>   #endif
> With some more macro abuse, we should be able to kill off ww->loop,

Killing off ww->loop in itself is a good thing, I think. But the below 
is a  bit hard to follow, I think, :/

> for (err = ({i915_gem_ww_ctx_init(ww, intr), -EDEADLK}); err == -EDEADLK; err = (err == -EDEADLK && !(err = i915_gem_ww_ctx_backoff(ww))) ? -EDEADLK : err)

Could we simply keep the inlines and use err=-EDEADLK as the loop 
condition instead?

/Thomas
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/i915_gem_ww.h b/drivers/gpu/drm/i915/i915_gem_ww.h
index f2d8769e4118..f6b1a796667b 100644
--- a/drivers/gpu/drm/i915/i915_gem_ww.h
+++ b/drivers/gpu/drm/i915/i915_gem_ww.h
@@ -11,11 +11,40 @@  struct i915_gem_ww_ctx {
 	struct ww_acquire_ctx ctx;
 	struct list_head obj_list;
 	struct drm_i915_gem_object *contended;
-	bool intr;
+	unsigned short intr;
+	unsigned short loop;
 };
 
 void i915_gem_ww_ctx_init(struct i915_gem_ww_ctx *ctx, bool intr);
 void i915_gem_ww_ctx_fini(struct i915_gem_ww_ctx *ctx);
 int __must_check i915_gem_ww_ctx_backoff(struct i915_gem_ww_ctx *ctx);
 void i915_gem_ww_unlock_single(struct drm_i915_gem_object *obj);
+
+/* Internal functions used by the inlines! Don't use. */
+static inline int __i915_gem_ww_fini(struct i915_gem_ww_ctx *ww, int err)
+{
+	ww->loop = 0;
+	if (err == -EDEADLK) {
+		err = i915_gem_ww_ctx_backoff(ww);
+		if (!err)
+			ww->loop = 1;
+	}
+
+	if (!ww->loop)
+		i915_gem_ww_ctx_fini(ww);
+
+	return err;
+}
+
+static inline void
+__i915_gem_ww_init(struct i915_gem_ww_ctx *ww, bool intr)
+{
+	i915_gem_ww_ctx_init(ww, intr);
+	ww->loop = 1;
+}
+
+#define for_i915_gem_ww(_ww, _err, _intr)			\
+	for (__i915_gem_ww_init(_ww, _intr); (_ww)->loop;	\
+	     _err = __i915_gem_ww_fini(_ww, _err))
+
 #endif