[dpdk-dev] [PATCH v2] doc: announce adoption of C11 atomic operations semantics

[Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>]

As agreed in the DPDK tech board [1], after 20.05 release, patches must
use C11 atomic operations semantics with the help of wrappers.

[1] http://mails.dpdk.org/archives/dev/2020-April/165143.html

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>
---
 doc/guides/rel_notes/deprecation.rst | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index 20aa745b7..01f99a0d6 100644
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -113,3 +113,16 @@ Deprecation Notices
   Python 2 support will be completely removed in 20.11.
   In 20.08, explicit deprecation warnings will be displayed when running
   scripts with Python 2.
+
+* rte_atomicNN_xxx: These APIs do not take memory order parameter. This does
+  not allow for writing optimized code for all the CPU architectures supported
+  in DPDK. DPDK will adopt C11 atomic operations semantics and provide wrappers
+  using C11 atomic built-ins. These wrappers must be used for patches that
+  need to be merged in 20.08 onwards. This change will not introduce any
+  performance degradation.
+
+* rte_smp_*mb: These APIs provide full barrier functionality. However, many
+  use cases do not require full barriers. To support such use cases, DPDK will
+  adopt C11 barrier semantics and provide wrappers using C11 atomic built-ins.
+  These wrappers must be used for patches that need to be merged in 20.08
+  onwards. This change will not introduce any performance degradation.
-- 
2.17.1