From: Stanislaw Kardach Date: Mon, 12 Apr 2021 08:28:59 +0000 (+0200) Subject: stack: allow lock-free only on relevant architectures X-Git-Url: http://git.droids-corp.org/?a=commitdiff_plain;h=1abb185d6cd41f83cd91eb6b1816c31e4bce887a;p=dpdk.git stack: allow lock-free only on relevant architectures Since commit 7911ba0473e0 ("stack: enable lock-free implementation for aarch64"), lock-free stack is supported on arm64 but this description was missing from the doxygen for the flag. Currently it is impossible to detect programmatically whether lock-free implementation of rte_stack is supported. One could check whether the header guard for lock-free stubs is defined (_RTE_STACK_LF_STUBS_H_) but that's an unstable implementation detail. Because of that currently all lock-free ring creations silently succeed (as long as the stack header is 16B long) which later leads to push and pop operations being NOPs. The observable effect is that stack_lf_autotest fails on platforms not supporting the lock-free. Instead it should just skip the lock-free test altogether. This commit adds a new errno value (ENOTSUP) that may be returned by rte_stack_create() to indicate that a given combination of flags is not supported on a current platform. This is detected by checking a compile-time flag in the include logic in rte_stack_lf.h which may be used by applications to check the lock-free support at compile time. Use the added RTE_STACK_LF_SUPPORTED flag to disable the lock-free stack tests at the compile time. Perf test doesn't fail because rte_ring_create() succeeds, however marking this test as skipped gives a better indication of what actually was tested. Fixes: 7911ba0473e0 ("stack: enable lock-free implementation for aarch64") Signed-off-by: Stanislaw Kardach Acked-by: Olivier Matz --- diff --git a/app/test/test_stack.c b/app/test/test_stack.c index 02422a32d6..00efb38e2a 100644 --- a/app/test/test_stack.c +++ b/app/test/test_stack.c @@ -373,7 +373,11 @@ test_stack(void) static int test_lf_stack(void) { +#if defined(RTE_STACK_LF_SUPPORTED) return __test_stack(RTE_STACK_F_LF); +#else + return TEST_SKIPPED; +#endif } REGISTER_TEST_COMMAND(stack_autotest, test_stack); diff --git a/app/test/test_stack_perf.c b/app/test/test_stack_perf.c index 3590625c49..4ee40d5d19 100644 --- a/app/test/test_stack_perf.c +++ b/app/test/test_stack_perf.c @@ -349,7 +349,11 @@ test_stack_perf(void) static int test_lf_stack_perf(void) { +#if defined(RTE_STACK_LF_SUPPORTED) return __test_stack_perf(RTE_STACK_F_LF); +#else + return TEST_SKIPPED; +#endif } REGISTER_TEST_COMMAND(stack_perf_autotest, test_stack_perf); diff --git a/doc/guides/rel_notes/release_21_05.rst b/doc/guides/rel_notes/release_21_05.rst index b3224dc332..cd33898c55 100644 --- a/doc/guides/rel_notes/release_21_05.rst +++ b/doc/guides/rel_notes/release_21_05.rst @@ -329,6 +329,10 @@ API Changes ``policer_action_recolor_supported`` and ``policer_action_drop_supported`` have been removed. +* stack: Lock-free ``rte_stack`` no longer silently ignores push and pop when + it's not supported on the current platform. Instead ``rte_stack_create()`` + fails and ``rte_errno`` is set to ``ENOTSUP``. + ABI Changes ----------- diff --git a/lib/stack/rte_stack.c b/lib/stack/rte_stack.c index 8a51fba17f..10d3b2eeb3 100644 --- a/lib/stack/rte_stack.c +++ b/lib/stack/rte_stack.c @@ -64,9 +64,11 @@ rte_stack_create(const char *name, unsigned int count, int socket_id, #ifdef RTE_ARCH_64 RTE_BUILD_BUG_ON(sizeof(struct rte_stack_lf_head) != 16); -#else +#endif +#if !defined(RTE_STACK_LF_SUPPORTED) if (flags & RTE_STACK_F_LF) { STACK_LOG_ERR("Lock-free stack is not supported on your platform\n"); + rte_errno = ENOTSUP; return NULL; } #endif diff --git a/lib/stack/rte_stack.h b/lib/stack/rte_stack.h index 395b9ef835..27640f87b2 100644 --- a/lib/stack/rte_stack.h +++ b/lib/stack/rte_stack.h @@ -89,7 +89,7 @@ struct rte_stack { /** * The stack uses lock-free push and pop functions. This flag is only - * supported on x86_64 platforms, currently. + * supported on x86_64 or arm64 platforms, currently. */ #define RTE_STACK_F_LF 0x0001 @@ -205,6 +205,7 @@ rte_stack_free_count(struct rte_stack *s) * - EEXIST - a stack with the same name already exists * - ENOMEM - insufficient memory to create the stack * - ENAMETOOLONG - name size exceeds RTE_STACK_NAMESIZE + * - ENOTSUP - platform does not support given flags combination. */ struct rte_stack * rte_stack_create(const char *name, unsigned int count, int socket_id, diff --git a/lib/stack/rte_stack_lf.h b/lib/stack/rte_stack_lf.h index eb106e64e6..f2b012cd0e 100644 --- a/lib/stack/rte_stack_lf.h +++ b/lib/stack/rte_stack_lf.h @@ -13,6 +13,11 @@ #else #include "rte_stack_lf_generic.h" #endif + +/** + * Indicates that RTE_STACK_F_LF is supported. + */ +#define RTE_STACK_LF_SUPPORTED #endif /**