[dpdk-dev] [PATCH v2] ring: use aligned memzone allocation
Ananyev, Konstantin
konstantin.ananyev at intel.com
Fri Jun 2 22:51:59 CEST 2017
> -----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
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