[dpdk-dev] [PATCH v8 01/11] eal/linux: add interrupt vectors support in intr_handle

[Liang, Cunming]

Hi Neil,

On 5/22/2015 1:58 AM, Neil Horman wrote:
> On Thu, May 21, 2015 at 10:43:00AM -0700, Stephen Hemminger wrote:
>> On Thu, 21 May 2015 06:32:02 -0400
>> Neil Horman <nhorman at tuxdriver.com> wrote:
>>
>>> On Thu, May 21, 2015 at 04:55:53PM +0800, Cunming Liang wrote:
>>>> The patch adds interrupt vectors support in rte_intr_handle.
>>>> 'vec_en' is set when interrupt vectors are detected and associated event fds are set.
>>>> Those event fds are stored in efds[].
>>>> 'intr_vec' is reserved for device driver to initialize the vector mapping table.
>>>> When the event fds add to a specified epoll instance, 'elist' will hold the rte_epoll_event object pointer.
>>>>
>>>> Signed-off-by: Danny Zhou <danny.zhou at intel.com>
>>>> Signed-off-by: Cunming Liang <cunming.liang at intel.com>
>>>> ---
>>>> v7 changes:
>>>>   - add eptrs[], it's used to store the register rte_epoll_event instances.
>>>>   - add vec_en, to log the vector capability status.
>>>>
>>>> v6 changes:
>>>>   - add mapping table between irq vector number and queue id.
>>>>
>>>> v5 changes:
>>>>   - Create this new patch file for changed struct rte_intr_handle that
>>>>     other patches depend on, to avoid breaking git bisect.
>>>>
>>>>   lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h | 10 ++++++++++
>>>>   1 file changed, 10 insertions(+)
>>>>
>>>> diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
>>>> index 6a159c7..27174df 100644
>>>> --- a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
>>>> +++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
>>>> @@ -38,6 +38,8 @@
>>>>   #ifndef _RTE_LINUXAPP_INTERRUPTS_H_
>>>>   #define _RTE_LINUXAPP_INTERRUPTS_H_
>>>>   
>>>> +#define RTE_MAX_RXTX_INTR_VEC_ID     32
>>>> +
>>>>   enum rte_intr_handle_type {
>>>>   	RTE_INTR_HANDLE_UNKNOWN = 0,
>>>>   	RTE_INTR_HANDLE_UIO,      /**< uio device handle */
>>>> @@ -48,6 +50,8 @@ enum rte_intr_handle_type {
>>>>   	RTE_INTR_HANDLE_MAX
>>>>   };
>>>>   
>>>> +struct rte_epoll_event;
>>>> +
>>>>   /** Handle for interrupts. */
>>>>   struct rte_intr_handle {
>>>>   	union {
>>>> @@ -57,6 +61,12 @@ struct rte_intr_handle {
>>>>   	};
>>>>   	int fd;	 /**< interrupt event file descriptor */
>>>>   	enum rte_intr_handle_type type;  /**< handle type */
>>>> +	uint32_t max_intr;               /**< max interrupt requested */
>>>> +	uint32_t nb_efd;                 /**< number of available efds */
>>>> +	int efds[RTE_MAX_RXTX_INTR_VEC_ID];  /**< intr vectors/efds mapping */
>>>> +	struct rte_epoll_event *elist[RTE_MAX_RXTX_INTR_VEC_ID];
>>>> +					 /**< intr vector epoll event ptr */
>>>> +	int *intr_vec;                   /**< intr vector number array */
>>>>   };
>>>>     
>>> This is going to be ABI breaking if this from test_interrupts.c:
>>> static struct rte_intr_handle intr_handles[TEST_INTERRUPT_HANDLE_MAX];
>>>
>>> is a plausible way of using this structure.  Even putting the data at the end of
>>> the structure won't help, as the array indicies are off
>> This needs to go in 2.0 and 2.0 has to have new ABI anyway.
>>
> We've already released 2.0, I think you mean 2.1, but 2.1 can't have a new ABI
> because we didn't announce it in 1.8.  The earliest we can update the ABI
> (according to the ABI docs) at this point is 2.2, since we need to announce the
> change in 2.1, then make it in 2.2
>
> Neil
>
I'll follow your guidance to send a separate patch to announce the ABI 
changes in this release.
For this code patch series, I propose to turn off the whole feature by 
default so as to avoid ABI broken in this release.
On next release v2.2, I'll send another cleanup patch to remove the 
feature macro.
In this way, we either won't block the feature code review or won't 
break ABI.
For users who are still going to use the feature in v2.1, they shall 
make sure aware of the impact of ABI changes and take risk to turn on 
the feature manually.
The v9 patch will include this part. Does it sound good to you?

Thanks,
Steve