doc: announce ABI change for ring structure

As discussed on the mailing list, the alignment constraint of
the ring structure can be relaxed.

Link: http://dpdk.org/dev/patchwork/patch/25039
Link: http://dpdk.org/dev/patchwork/patch/26103
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: John McNamara <john.mcnamara@intel.com>
Acked-by: Anatoly Burakov <anatoly.burakov@intel.com>

diff --git a/doc/guides/rel_notes/deprecation.rst b/doc/guides/rel_notes/deprecation.rst
index 13e8543..d59ad59 100644 (file)
--- a/doc/guides/rel_notes/deprecation.rst
+++ b/doc/guides/rel_notes/deprecation.rst
@@ -53,3 +53,9 @@ Deprecation Notices
 
 * librte_meter: The API will change to accommodate configuration profiles.
   Most of the API functions will have an additional opaque parameter.
+
+* ring: The alignment constraints on the ring structure will be relaxed
+  to one cache line instead of two, and an empty cache line padding will
+  be added between the producer and consumer structures. The size of the
+  structure and the offset of the fields will remain the same on
+  platforms with 64B cache line, but will change on other platforms.