[net-next,1/8] ptr_ring: introduce batch dequeuing
diff mbox series

Message ID 1490069087-4783-2-git-send-email-jasowang@redhat.com
State New, archived
Headers show
Series
  • vhost-net rx batching
Related show

Commit Message

Jason Wang March 21, 2017, 4:04 a.m. UTC
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 include/linux/ptr_ring.h | 65 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

Comments

Sergei Shtylyov March 21, 2017, 10:25 a.m. UTC | #1
Hello!

On 3/21/2017 7:04 AM, Jason Wang wrote:

> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  include/linux/ptr_ring.h | 65 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 65 insertions(+)
>
> diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
> index 6c70444..4771ded 100644
> --- a/include/linux/ptr_ring.h
> +++ b/include/linux/ptr_ring.h
> @@ -247,6 +247,22 @@ static inline void *__ptr_ring_consume(struct ptr_ring *r)
>  	return ptr;
>  }
>
> +static inline int __ptr_ring_consume_batched(struct ptr_ring *r,
> +					     void **array, int n)
> +{
> +	void *ptr;
> +	int i = 0;
> +
> +	while (i < n) {

    Hm, why not *for*?

> +		ptr = __ptr_ring_consume(r);
> +		if (!ptr)
> +			break;
> +		array[i++] = ptr;
> +	}
> +
> +	return i;
> +}
> +
>  /*
>   * Note: resize (below) nests producer lock within consumer lock, so if you
>   * call this in interrupt or BH context, you must disable interrupts/BH when
> @@ -297,6 +313,55 @@ static inline void *ptr_ring_consume_bh(struct ptr_ring *r)
[...]

MBR, Sergei
Jason Wang March 22, 2017, 3:16 a.m. UTC | #2
On 2017年03月21日 18:25, Sergei Shtylyov wrote:
> Hello!
>
> On 3/21/2017 7:04 AM, Jason Wang wrote:
>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  include/linux/ptr_ring.h | 65 
>> ++++++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 65 insertions(+)
>>
>> diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
>> index 6c70444..4771ded 100644
>> --- a/include/linux/ptr_ring.h
>> +++ b/include/linux/ptr_ring.h
>> @@ -247,6 +247,22 @@ static inline void *__ptr_ring_consume(struct 
>> ptr_ring *r)
>>      return ptr;
>>  }
>>
>> +static inline int __ptr_ring_consume_batched(struct ptr_ring *r,
>> +                         void **array, int n)
>> +{
>> +    void *ptr;
>> +    int i = 0;
>> +
>> +    while (i < n) {
>
>    Hm, why not *for*?

Yes, it maybe better, if there's other comment on the series, will 
change it in next version.

Thanks
Michael S. Tsirkin March 22, 2017, 1:43 p.m. UTC | #3
On Tue, Mar 21, 2017 at 12:04:40PM +0800, Jason Wang wrote:
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  include/linux/ptr_ring.h | 65 ++++++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 65 insertions(+)
> 
> diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
> index 6c70444..4771ded 100644
> --- a/include/linux/ptr_ring.h
> +++ b/include/linux/ptr_ring.h
> @@ -247,6 +247,22 @@ static inline void *__ptr_ring_consume(struct ptr_ring *r)
>  	return ptr;
>  }
>  
> +static inline int __ptr_ring_consume_batched(struct ptr_ring *r,
> +					     void **array, int n)
> +{
> +	void *ptr;
> +	int i = 0;
> +
> +	while (i < n) {
> +		ptr = __ptr_ring_consume(r);
> +		if (!ptr)
> +			break;
> +		array[i++] = ptr;
> +	}
> +
> +	return i;
> +}
> +
>  /*
>   * Note: resize (below) nests producer lock within consumer lock, so if you
>   * call this in interrupt or BH context, you must disable interrupts/BH when


This ignores the comment above that function:

/* Note: callers invoking this in a loop must use a compiler barrier,
 * for example cpu_relax().
 */

Also - it looks like it shouldn't matter if reads are reordered but I wonder.
Thoughts? Including some reasoning about it in commit log would be nice.

> @@ -297,6 +313,55 @@ static inline void *ptr_ring_consume_bh(struct ptr_ring *r)
>  	return ptr;
>  }
>  
> +static inline int ptr_ring_consume_batched(struct ptr_ring *r,
> +					   void **array, int n)
> +{
> +	int ret;
> +
> +	spin_lock(&r->consumer_lock);
> +	ret = __ptr_ring_consume_batched(r, array, n);
> +	spin_unlock(&r->consumer_lock);
> +
> +	return ret;
> +}
> +
> +static inline int ptr_ring_consume_batched_irq(struct ptr_ring *r,
> +					       void **array, int n)
> +{
> +	int ret;
> +
> +	spin_lock_irq(&r->consumer_lock);
> +	ret = __ptr_ring_consume_batched(r, array, n);
> +	spin_unlock_irq(&r->consumer_lock);
> +
> +	return ret;
> +}
> +
> +static inline int ptr_ring_consume_batched_any(struct ptr_ring *r,
> +					       void **array, int n)
> +{
> +	unsigned long flags;
> +	int ret;
> +
> +	spin_lock_irqsave(&r->consumer_lock, flags);
> +	ret = __ptr_ring_consume_batched(r, array, n);
> +	spin_unlock_irqrestore(&r->consumer_lock, flags);
> +
> +	return ret;
> +}
> +
> +static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
> +					      void **array, int n)
> +{
> +	int ret;
> +
> +	spin_lock_bh(&r->consumer_lock);
> +	ret = __ptr_ring_consume_batched(r, array, n);
> +	spin_unlock_bh(&r->consumer_lock);
> +
> +	return ret;
> +}
> +
>  /* Cast to structure type and call a function without discarding from FIFO.
>   * Function must return a value.
>   * Callers must take consumer_lock.
> -- 
> 2.7.4
Jason Wang March 23, 2017, 5:33 a.m. UTC | #4
On 2017年03月22日 21:43, Michael S. Tsirkin wrote:
> On Tue, Mar 21, 2017 at 12:04:40PM +0800, Jason Wang wrote:
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>   include/linux/ptr_ring.h | 65 ++++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 65 insertions(+)
>>
>> diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
>> index 6c70444..4771ded 100644
>> --- a/include/linux/ptr_ring.h
>> +++ b/include/linux/ptr_ring.h
>> @@ -247,6 +247,22 @@ static inline void *__ptr_ring_consume(struct ptr_ring *r)
>>   	return ptr;
>>   }
>>   
>> +static inline int __ptr_ring_consume_batched(struct ptr_ring *r,
>> +					     void **array, int n)
>> +{
>> +	void *ptr;
>> +	int i = 0;
>> +
>> +	while (i < n) {
>> +		ptr = __ptr_ring_consume(r);
>> +		if (!ptr)
>> +			break;
>> +		array[i++] = ptr;
>> +	}
>> +
>> +	return i;
>> +}
>> +
>>   /*
>>    * Note: resize (below) nests producer lock within consumer lock, so if you
>>    * call this in interrupt or BH context, you must disable interrupts/BH when
>
> This ignores the comment above that function:
>
> /* Note: callers invoking this in a loop must use a compiler barrier,
>   * for example cpu_relax().
>   */

Yes, __ptr_ring_swap_queue() ignores this too.

>
> Also - it looks like it shouldn't matter if reads are reordered but I wonder.
> Thoughts? Including some reasoning about it in commit log would be nice.

Yes, I think it doesn't matter in this case, it matters only for batched 
producing.

Thanks

>
>> @@ -297,6 +313,55 @@ static inline void *ptr_ring_consume_bh(struct ptr_ring *r)
>>   	return ptr;
>>   }
>>   
>> +static inline int ptr_ring_consume_batched(struct ptr_ring *r,
>> +					   void **array, int n)
>> +{
>> +	int ret;
>> +
>> +	spin_lock(&r->consumer_lock);
>> +	ret = __ptr_ring_consume_batched(r, array, n);
>> +	spin_unlock(&r->consumer_lock);
>> +
>> +	return ret;
>> +}
>> +
>> +static inline int ptr_ring_consume_batched_irq(struct ptr_ring *r,
>> +					       void **array, int n)
>> +{
>> +	int ret;
>> +
>> +	spin_lock_irq(&r->consumer_lock);
>> +	ret = __ptr_ring_consume_batched(r, array, n);
>> +	spin_unlock_irq(&r->consumer_lock);
>> +
>> +	return ret;
>> +}
>> +
>> +static inline int ptr_ring_consume_batched_any(struct ptr_ring *r,
>> +					       void **array, int n)
>> +{
>> +	unsigned long flags;
>> +	int ret;
>> +
>> +	spin_lock_irqsave(&r->consumer_lock, flags);
>> +	ret = __ptr_ring_consume_batched(r, array, n);
>> +	spin_unlock_irqrestore(&r->consumer_lock, flags);
>> +
>> +	return ret;
>> +}
>> +
>> +static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
>> +					      void **array, int n)
>> +{
>> +	int ret;
>> +
>> +	spin_lock_bh(&r->consumer_lock);
>> +	ret = __ptr_ring_consume_batched(r, array, n);
>> +	spin_unlock_bh(&r->consumer_lock);
>> +
>> +	return ret;
>> +}
>> +
>>   /* Cast to structure type and call a function without discarding from FIFO.
>>    * Function must return a value.
>>    * Callers must take consumer_lock.
>> -- 
>> 2.7.4

Patch
diff mbox series

diff --git a/include/linux/ptr_ring.h b/include/linux/ptr_ring.h
index 6c70444..4771ded 100644
--- a/include/linux/ptr_ring.h
+++ b/include/linux/ptr_ring.h
@@ -247,6 +247,22 @@  static inline void *__ptr_ring_consume(struct ptr_ring *r)
 	return ptr;
 }
 
+static inline int __ptr_ring_consume_batched(struct ptr_ring *r,
+					     void **array, int n)
+{
+	void *ptr;
+	int i = 0;
+
+	while (i < n) {
+		ptr = __ptr_ring_consume(r);
+		if (!ptr)
+			break;
+		array[i++] = ptr;
+	}
+
+	return i;
+}
+
 /*
  * Note: resize (below) nests producer lock within consumer lock, so if you
  * call this in interrupt or BH context, you must disable interrupts/BH when
@@ -297,6 +313,55 @@  static inline void *ptr_ring_consume_bh(struct ptr_ring *r)
 	return ptr;
 }
 
+static inline int ptr_ring_consume_batched(struct ptr_ring *r,
+					   void **array, int n)
+{
+	int ret;
+
+	spin_lock(&r->consumer_lock);
+	ret = __ptr_ring_consume_batched(r, array, n);
+	spin_unlock(&r->consumer_lock);
+
+	return ret;
+}
+
+static inline int ptr_ring_consume_batched_irq(struct ptr_ring *r,
+					       void **array, int n)
+{
+	int ret;
+
+	spin_lock_irq(&r->consumer_lock);
+	ret = __ptr_ring_consume_batched(r, array, n);
+	spin_unlock_irq(&r->consumer_lock);
+
+	return ret;
+}
+
+static inline int ptr_ring_consume_batched_any(struct ptr_ring *r,
+					       void **array, int n)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&r->consumer_lock, flags);
+	ret = __ptr_ring_consume_batched(r, array, n);
+	spin_unlock_irqrestore(&r->consumer_lock, flags);
+
+	return ret;
+}
+
+static inline int ptr_ring_consume_batched_bh(struct ptr_ring *r,
+					      void **array, int n)
+{
+	int ret;
+
+	spin_lock_bh(&r->consumer_lock);
+	ret = __ptr_ring_consume_batched(r, array, n);
+	spin_unlock_bh(&r->consumer_lock);
+
+	return ret;
+}
+
 /* Cast to structure type and call a function without discarding from FIFO.
  * Function must return a value.
  * Callers must take consumer_lock.