[dpdk-dev] [PATCH v2] ring: use aligned memzone allocation

[Ananyev, Konstantin]

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Daniel Verkamp
> Sent: Friday, June 2, 2017 9:12 PM
> To: dev at dpdk.org
> Cc: Verkamp, Daniel <daniel.verkamp at intel.com>
> Subject: [dpdk-dev] [PATCH v2] ring: use aligned memzone allocation
> 
> rte_memzone_reserve() provides cache line alignment, but
> struct rte_ring may require more than cache line alignment: on x86-64,
> it needs 128-byte alignment due to PROD_ALIGN and CONS_ALIGN, which are
> 128 bytes, but cache line size is 64 bytes.

Hmm but what for?
I understand we need our rte_ring cche-line aligned,
but why do you want it 2 cache-line aligned?
Konstantin 

> 
> Fixes runtime warnings with UBSan enabled.
> 
> Fixes: d9f0d3a1ffd4 ("ring: remove split cacheline build setting")
> 
> Signed-off-by: Daniel Verkamp <daniel.verkamp at intel.com>
> ---
> 
> v2: fixed checkpatch warnings
> 
>  lib/librte_ring/rte_ring.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/librte_ring/rte_ring.c b/lib/librte_ring/rte_ring.c
> index 5f98c33..6f58faf 100644
> --- a/lib/librte_ring/rte_ring.c
> +++ b/lib/librte_ring/rte_ring.c
> @@ -189,7 +189,8 @@ rte_ring_create(const char *name, unsigned count, int socket_id,
>  	/* reserve a memory zone for this ring. If we can't get rte_config or
>  	 * we are secondary process, the memzone_reserve function will set
>  	 * rte_errno for us appropriately - hence no check in this this function */
> -	mz = rte_memzone_reserve(mz_name, ring_size, socket_id, mz_flags);
> +	mz = rte_memzone_reserve_aligned(mz_name, ring_size, socket_id,
> +					 mz_flags, __alignof__(*r));
>  	if (mz != NULL) {
>  		r = mz->addr;
>  		/* no need to check return value here, we already checked the
> --
> 2.9.4