Re: [dpdk-dev] [PATCH v3] eal: use c11 atomic built-ins for interrupt status

[David Marchand <david.marchand@redhat.com>]

On Thu, Jul 9, 2020 at 10:35 AM Phil Yang <phil.yang@arm.com> wrote:
>
> The event status is defined as a volatile variable and shared between
> threads. Use c11 atomic built-ins with explicit ordering instead of
> rte_atomic ops which enforce unnecessary barriers on aarch64.
>
> The event status has been cleaned up by the compare-and-swap operation
> when we free the event data, so there is no need to set it to invalid
> after that.
>
> Signed-off-by: Phil Yang <phil.yang@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Harman Kalra <hkalra@marvell.com>
> ---
> v3:
> Fixed typo.
>
> v2:
> 1. Fixed typo.
> 2. Updated libabigail.abignore to pass ABI check.
> 3. Merged v1 two patches into one patch.
>
>  devtools/libabigail.abignore                |  4 +++
>  lib/librte_eal/include/rte_eal_interrupts.h |  2 +-
>  lib/librte_eal/linux/eal_interrupts.c       | 48 ++++++++++++++++++++---------
>  3 files changed, 38 insertions(+), 16 deletions(-)
>
> diff --git a/devtools/libabigail.abignore b/devtools/libabigail.abignore
> index 0133f75..daa4631 100644
> --- a/devtools/libabigail.abignore
> +++ b/devtools/libabigail.abignore
> @@ -48,6 +48,10 @@
>          changed_enumerators = RTE_CRYPTO_AEAD_LIST_END
>  [suppress_variable]
>          name = rte_crypto_aead_algorithm_strings
> +; Ignore updates of epoll event
> +[suppress_type]
> +        type_kind = struct
> +        name = rte_epoll_event

In general, ignoring all changes on a structure is risky.
But the risk is acceptable as long as we remember this for the rest of
the 20.08 release (and we will start from scratch for 20.11).


Without any comment from others, I'll merge this by the end of (my) day.

Thanks.

-- 
David Marchand