[v6,35/39] dispatcher: use C11 alignas

Message ID 1708971946-18231-36-git-send-email-roretzla@linux.microsoft.com (mailing list archive)
State Superseded, archived
Delegated to: Thomas Monjalon
Series use C11 alignas |


Context Check Description
ci/checkpatch success coding style OK

Commit Message

Tyler Retzlaff Feb. 26, 2024, 6:25 p.m. UTC
  The current location used for __rte_aligned(a) for alignment of types
and variables is not compatible with MSVC. There is only a single
location accepted by both toolchains.

For variables standard C11 offers alignas(a) supported by conformant
compilers i.e. both MSVC and GCC.

For types the standard offers no alignment facility that compatibly
interoperates with C and C++ but may be achieved by relocating the
placement of __rte_aligned(a) to the aforementioned location accepted
by all currently supported toolchains.

To allow alignment for both compilers do the following:

* Move __rte_aligned from the end of {struct,union} definitions to
  be between {struct,union} and tag.

  The placement between {struct,union} and the tag allows the desired
  alignment to be imparted on the type regardless of the toolchain being
  used for all of GCC, LLVM, MSVC compilers building both C and C++.

* Replace use of __rte_aligned(a) on variables/fields with alignas(a).

Signed-off-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
Acked-by: Morten Brørup <mb@smartsharesystems.com>
 lib/dispatcher/rte_dispatcher.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)


diff --git a/lib/dispatcher/rte_dispatcher.c b/lib/dispatcher/rte_dispatcher.c
index f546d75..7934917 100644
--- a/lib/dispatcher/rte_dispatcher.c
+++ b/lib/dispatcher/rte_dispatcher.c
@@ -41,7 +41,7 @@  struct rte_dispatcher_finalizer {
 	void *finalize_data;
-struct rte_dispatcher_lcore {
+struct __rte_cache_aligned rte_dispatcher_lcore {
 	uint8_t num_ports;
 	uint16_t num_handlers;
 	int32_t prio_count;
@@ -49,7 +49,7 @@  struct rte_dispatcher_lcore {
 	struct rte_dispatcher_handler handlers[EVD_MAX_HANDLERS];
 	struct rte_dispatcher_stats stats;
-} __rte_cache_aligned;
 struct rte_dispatcher {
 	uint8_t event_dev_id;