Re: [PATCH liburing v1 1/2] examples/zcrx: Use PAGE_SIZE for ring refill alignment

[Haiyue Wang <haiyuewa@163.com>]

On 2025/4/19 20:51, Jens Axboe wrote:
> On 4/19/25 3:57 AM, Haiyue Wang wrote:
>> According to the 'Create refill ring' section in [1], use the macro
>> PAGE_SIZE instead of 4096 hard code number.
>>
>> [1]: https://www.kernel.org/doc/html/latest/networking/iou-zcrx.html
>>
>> Signed-off-by: Haiyue Wang <haiyuewa@163.com>
>> ---
>>   examples/zcrx.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/examples/zcrx.c b/examples/zcrx.c
>> index 8393cfe..c96bbfe 100644
>> --- a/examples/zcrx.c
>> +++ b/examples/zcrx.c
>> @@ -66,7 +66,7 @@ static inline size_t get_refill_ring_size(unsigned int rq_entries)
>>   	ring_size = rq_entries * sizeof(struct io_uring_zcrx_rqe);
>>   	/* add space for the header (head/tail/etc.) */
>>   	ring_size += PAGE_SIZE;
>> -	return T_ALIGN_UP(ring_size, 4096);
>> +	return T_ALIGN_UP(ring_size, PAGE_SIZE);
>>   }
>>   
>>   static void setup_zcrx(struct io_uring *ring)
> 
> Well, in that same file:
> 
> #define PAGE_SIZE (4096)
> 
> so this won't really fix anything. Examples or test code
> should use:

The original plan is to make the code consistent for page size as:
	ring_size += PAGE_SIZE

> 
> sysconf(_SC_PAGESIZE)
> 

So fix it as 'examples/proxy'?

	static long page_size;

	page_size = sysconf(_SC_PAGESIZE);
	if (page_size < 0) {
		perror("sysconf(_SC_PAGESIZE)");
		return 1;
	}

> to get the page size at runtime.
>