stack: enable lock-free implementation for aarch64

Enable both C11 atomic and non C11 atomic lock-free stack for aarch64.

Introduced a new header to reduce the ifdef clutter across generic and C11
files. The rte_stack_lf_stubs.h contains stub implementations of
__rte_stack_lf_count, __rte_stack_lf_push_elems and
__rte_stack_lf_pop_elems.

Suggested-by: Gage Eads <gage.eads@intel.com>
Suggested-by: Jerin Jacob <jerinj@marvell.com>
Signed-off-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Tested-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Acked-by: Jerin Jacob <jerinj@marvell.com>

diff --git a/doc/guides/prog_guide/env_abstraction_layer.rst b/doc/guides/prog_guide/env_abstraction_layer.rst
index 94f30fd..6e59fae 100644 (file)
--- a/doc/guides/prog_guide/env_abstraction_layer.rst
+++ b/doc/guides/prog_guide/env_abstraction_layer.rst
@@ -648,8 +648,8 @@ Known Issues
   Alternatively, applications can use the lock-free stack mempool handler. When
   considering this handler, note that:
 
-  - It is currently limited to the x86_64 platform, because it uses an
-    instruction (16-byte compare-and-swap) that is not yet available on other
+  - It is currently limited to the aarch64 and x86_64 platforms, because it uses
+    an instruction (16-byte compare-and-swap) that is not yet available on other
     platforms.
   - It has worse average-case performance than the non-preemptive rte_ring, but
     software caching (e.g. the mempool cache) can mitigate this by reducing the

diff --git a/doc/guides/rel_notes/release_19_11.rst b/doc/guides/rel_notes/release_19_11.rst
index 85953b9..b8386d4 100644 (file)
--- a/doc/guides/rel_notes/release_19_11.rst
+++ b/doc/guides/rel_notes/release_19_11.rst
@@ -56,6 +56,10 @@ New Features
      Also, make sure to start the actual text at the margin.
      =========================================================
 
+* **Added Lock-free Stack for aarch64.**
+
+  The lock-free stack implementation is enabled for aarch64 platforms.
+
 * **Added Hisilicon hns3 PMD.**
 
   Added the new ``hns3`` net driver for the inbuilt Hisilicon Network

diff --git a/lib/librte_stack/Makefile b/lib/librte_stack/Makefile
index 8d18ce5..b5e5bed 100644 (file)
--- a/lib/librte_stack/Makefile
+++ b/lib/librte_stack/Makefile
@@ -24,6 +24,7 @@ SYMLINK-$(CONFIG_RTE_LIBRTE_STACK)-include := rte_stack.h \
                                              rte_stack_std.h \
                                              rte_stack_lf.h \
                                              rte_stack_lf_generic.h \
-                                             rte_stack_lf_c11.h
+                                             rte_stack_lf_c11.h \
+                                             rte_stack_lf_stubs.h
 
 include $(RTE_SDK)/mk/rte.lib.mk

diff --git a/lib/librte_stack/rte_stack_lf.h b/lib/librte_stack/rte_stack_lf.h
index f5581f0..e67630c 100644 (file)
--- a/lib/librte_stack/rte_stack_lf.h
+++ b/lib/librte_stack/rte_stack_lf.h
@@ -5,11 +5,15 @@
 #ifndef _RTE_STACK_LF_H_
 #define _RTE_STACK_LF_H_
 
+#if !(defined(RTE_ARCH_X86_64) || defined(RTE_ARCH_ARM64))
+#include "rte_stack_lf_stubs.h"
+#else
 #ifdef RTE_USE_C11_MEM_MODEL
 #include "rte_stack_lf_c11.h"
 #else
 #include "rte_stack_lf_generic.h"
 #endif
+#endif
 
 /**
  * @internal Push several objects on the lock-free stack (MT-safe).

diff --git a/lib/librte_stack/rte_stack_lf_c11.h b/lib/librte_stack/rte_stack_lf_c11.h
index 3d677ae..999359f 100644 (file)
--- a/lib/librte_stack/rte_stack_lf_c11.h
+++ b/lib/librte_stack/rte_stack_lf_c11.h
@@ -36,12 +36,6 @@ __rte_stack_lf_push_elems(struct rte_stack_lf_list *list,
                          struct rte_stack_lf_elem *last,
                          unsigned int num)
 {
-#ifndef RTE_ARCH_X86_64
-       RTE_SET_USED(first);
-       RTE_SET_USED(last);
-       RTE_SET_USED(list);
-       RTE_SET_USED(num);
-#else
        struct rte_stack_lf_head old_head;
        int success;
 
@@ -79,7 +73,6 @@ __rte_stack_lf_push_elems(struct rte_stack_lf_list *list,
         * to the LIFO len update.
         */
        __atomic_add_fetch(&list->len, num, __ATOMIC_RELEASE);
-#endif
 }
 
 static __rte_always_inline struct rte_stack_lf_elem *
@@ -88,14 +81,6 @@ __rte_stack_lf_pop_elems(struct rte_stack_lf_list *list,
                         void **obj_table,
                         struct rte_stack_lf_elem **last)
 {
-#ifndef RTE_ARCH_X86_64
-       RTE_SET_USED(obj_table);
-       RTE_SET_USED(last);
-       RTE_SET_USED(list);
-       RTE_SET_USED(num);
-
-       return NULL;
-#else
        struct rte_stack_lf_head old_head;
        uint64_t len;
        int success;
@@ -169,7 +154,6 @@ __rte_stack_lf_pop_elems(struct rte_stack_lf_list *list,
        } while (success == 0);
 
        return old_head.top;
-#endif
 }
 
 #endif /* _RTE_STACK_LF_C11_H_ */

diff --git a/lib/librte_stack/rte_stack_lf_generic.h b/lib/librte_stack/rte_stack_lf_generic.h
index 3182151..3abbb53 100644 (file)
--- a/lib/librte_stack/rte_stack_lf_generic.h
+++ b/lib/librte_stack/rte_stack_lf_generic.h
@@ -36,12 +36,6 @@ __rte_stack_lf_push_elems(struct rte_stack_lf_list *list,
                          struct rte_stack_lf_elem *last,
                          unsigned int num)
 {
-#ifndef RTE_ARCH_X86_64
-       RTE_SET_USED(first);
-       RTE_SET_USED(last);
-       RTE_SET_USED(list);
-       RTE_SET_USED(num);
-#else
        struct rte_stack_lf_head old_head;
        int success;
 
@@ -75,7 +69,6 @@ __rte_stack_lf_push_elems(struct rte_stack_lf_list *list,
        } while (success == 0);
 
        rte_atomic64_add((rte_atomic64_t *)&list->len, num);
-#endif
 }
 
 static __rte_always_inline struct rte_stack_lf_elem *
@@ -84,14 +77,6 @@ __rte_stack_lf_pop_elems(struct rte_stack_lf_list *list,
                         void **obj_table,
                         struct rte_stack_lf_elem **last)
 {
-#ifndef RTE_ARCH_X86_64
-       RTE_SET_USED(obj_table);
-       RTE_SET_USED(last);
-       RTE_SET_USED(list);
-       RTE_SET_USED(num);
-
-       return NULL;
-#else
        struct rte_stack_lf_head old_head;
        int success;
 
@@ -159,7 +144,6 @@ __rte_stack_lf_pop_elems(struct rte_stack_lf_list *list,
        } while (success == 0);
 
        return old_head.top;
-#endif
 }
 
 #endif /* _RTE_STACK_LF_GENERIC_H_ */

diff --git a/lib/librte_stack/rte_stack_lf_stubs.h b/lib/librte_stack/rte_stack_lf_stubs.h
new file mode 100644 (file)
index 0000000..a05abf1
--- /dev/null
+++ b/lib/librte_stack/rte_stack_lf_stubs.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2019 Arm Limited
+ */
+
+#ifndef _RTE_STACK_LF_STUBS_H_
+#define _RTE_STACK_LF_STUBS_H_
+
+#include <rte_common.h>
+
+static __rte_always_inline unsigned int
+__rte_stack_lf_count(struct rte_stack *s)
+{
+       RTE_SET_USED(s);
+
+       return 0;
+}
+
+static __rte_always_inline void
+__rte_stack_lf_push_elems(struct rte_stack_lf_list *list,
+                         struct rte_stack_lf_elem *first,
+                         struct rte_stack_lf_elem *last,
+                         unsigned int num)
+{
+       RTE_SET_USED(first);
+       RTE_SET_USED(last);
+       RTE_SET_USED(list);
+       RTE_SET_USED(num);
+}
+
+static __rte_always_inline struct rte_stack_lf_elem *
+__rte_stack_lf_pop_elems(struct rte_stack_lf_list *list,
+                        unsigned int num,
+                        void **obj_table,
+                        struct rte_stack_lf_elem **last)
+{
+       RTE_SET_USED(obj_table);
+       RTE_SET_USED(last);
+       RTE_SET_USED(list);
+       RTE_SET_USED(num);
+
+       return NULL;
+}
+
+#endif /* _RTE_STACK_LF_STUBS_H_ */