From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 9EA22A0547; Fri, 10 Sep 2021 01:14:07 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id F16734114F; Fri, 10 Sep 2021 01:13:48 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mails.dpdk.org (Postfix) with ESMTP id AF3A541103 for ; Fri, 10 Sep 2021 01:13:42 +0200 (CEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 23C211063; Thu, 9 Sep 2021 16:13:42 -0700 (PDT) Received: from 2p2660v4-1.austin.arm.com (2p2660v4-1.austin.arm.com [10.118.13.211]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1C7583F766; Thu, 9 Sep 2021 16:13:42 -0700 (PDT) From: Honnappa Nagarahalli To: dev@dpdk.org, honnappa.nagarahalli@arm.com, konstantin.ananyev@intel.com, david.marchand@redhat.com, feifei.wang2@arm.com Cc: ruifeng.wang@arm.com, nd@arm.com, Feifei Wang Date: Thu, 9 Sep 2021 18:13:11 -0500 Message-Id: <20210909231312.2572006-6-honnappa.nagarahalli@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210909231312.2572006-1-honnappa.nagarahalli@arm.com> References: <20210224212018.17576-1-honnappa.nagarahalli@arm.com> <20210909231312.2572006-1-honnappa.nagarahalli@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [dpdk-dev] [PATCH v2 5/6] eal: ensure memory operations are visible to main X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Ensure that the memory operations in worker thread, that happen before it returns the status of the assigned function, are visible to the main thread. Signed-off-by: Honnappa Nagarahalli Reviewed-by: Feifei Wang --- lib/eal/common/eal_common_launch.c | 2 -- lib/eal/freebsd/eal_thread.c | 22 ++++++++++++++++++---- lib/eal/linux/eal_thread.c | 23 ++++++++++++++++++----- lib/eal/windows/eal_thread.c | 21 +++++++++++++++++---- 4 files changed, 53 insertions(+), 15 deletions(-) diff --git a/lib/eal/common/eal_common_launch.c b/lib/eal/common/eal_common_launch.c index 4bc842417a..e95dadffb3 100644 --- a/lib/eal/common/eal_common_launch.c +++ b/lib/eal/common/eal_common_launch.c @@ -27,8 +27,6 @@ rte_eal_wait_lcore(unsigned worker_id) __ATOMIC_ACQUIRE) != WAIT) rte_pause(); - rte_rmb(); - return lcore_config[worker_id].ret; } diff --git a/lib/eal/freebsd/eal_thread.c b/lib/eal/freebsd/eal_thread.c index e5e3edf79b..3b18030d73 100644 --- a/lib/eal/freebsd/eal_thread.c +++ b/lib/eal/freebsd/eal_thread.c @@ -39,7 +39,11 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned worker_id) int w2m = lcore_config[worker_id].pipe_worker2main[0]; int rc = -EBUSY; - if (lcore_config[worker_id].state != WAIT) + /* Check if the worker is in 'WAIT' state. Use acquire order + * since 'state' variable is used as the guard variable. + */ + if (__atomic_load_n(&lcore_config[worker_id].state, + __ATOMIC_ACQUIRE) != WAIT) goto finish; lcore_config[worker_id].arg = arg; @@ -115,7 +119,11 @@ eal_thread_loop(__rte_unused void *arg) if (n <= 0) rte_panic("cannot read on configuration pipe\n"); - lcore_config[lcore_id].state = RUNNING; + /* Set the state to 'RUNNING'. Use release order + * since 'state' variable is used as the guard variable. + */ + __atomic_store_n(&lcore_config[lcore_id].state, RUNNING, + __ATOMIC_RELEASE); /* send ack */ n = 0; @@ -139,8 +147,14 @@ eal_thread_loop(__rte_unused void *arg) lcore_config[lcore_id].ret = ret; lcore_config[lcore_id].f = NULL; lcore_config[lcore_id].arg = NULL; - rte_wmb(); - lcore_config[lcore_id].state = WAIT; + + /* Store the state with release order to ensure that + * the memory operations from the worker thread + * are completed before the state is updated. + * Use 'state' as the guard variable. + */ + __atomic_store_n(&lcore_config[lcore_id].state, WAIT, + __ATOMIC_RELEASE); } /* never reached */ diff --git a/lib/eal/linux/eal_thread.c b/lib/eal/linux/eal_thread.c index c79e09c9ad..c7f0f9b2f7 100644 --- a/lib/eal/linux/eal_thread.c +++ b/lib/eal/linux/eal_thread.c @@ -39,13 +39,17 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned int worker_id) int w2m = lcore_config[worker_id].pipe_worker2main[0]; int rc = -EBUSY; - if (lcore_config[worker_id].state != WAIT) + /* Check if the worker is in 'WAIT' state. Use acquire order + * since 'state' variable is used as the guard variable. + */ + if (__atomic_load_n(&lcore_config[worker_id].state, + __ATOMIC_ACQUIRE) != WAIT) goto finish; lcore_config[worker_id].arg = arg; /* Ensure that all the memory operations are completed * before the worker thread starts running the function. - * Use worker thread function as the guard variable. + * Use worker thread function pointer as the guard variable. */ __atomic_store_n(&lcore_config[worker_id].f, f, __ATOMIC_RELEASE); @@ -115,7 +119,11 @@ eal_thread_loop(__rte_unused void *arg) if (n <= 0) rte_panic("cannot read on configuration pipe\n"); - lcore_config[lcore_id].state = RUNNING; + /* Set the state to 'RUNNING'. Use release order + * since 'state' variable is used as the guard variable. + */ + __atomic_store_n(&lcore_config[lcore_id].state, RUNNING, + __ATOMIC_RELEASE); /* send ack */ n = 0; @@ -139,9 +147,14 @@ eal_thread_loop(__rte_unused void *arg) lcore_config[lcore_id].ret = ret; lcore_config[lcore_id].f = NULL; lcore_config[lcore_id].arg = NULL; - rte_wmb(); - lcore_config[lcore_id].state = WAIT; + /* Store the state with release order to ensure that + * the memory operations from the worker thread + * are completed before the state is updated. + * Use 'state' as the guard variable. + */ + __atomic_store_n(&lcore_config[lcore_id].state, WAIT, + __ATOMIC_RELEASE); } /* never reached */ diff --git a/lib/eal/windows/eal_thread.c b/lib/eal/windows/eal_thread.c index 977911905e..54fa93fa62 100644 --- a/lib/eal/windows/eal_thread.c +++ b/lib/eal/windows/eal_thread.c @@ -29,7 +29,11 @@ rte_eal_remote_launch(lcore_function_t *f, void *arg, unsigned int worker_id) int m2w = lcore_config[worker_id].pipe_main2worker[1]; int w2m = lcore_config[worker_id].pipe_worker2main[0]; - if (lcore_config[worker_id].state != WAIT) + /* Check if the worker is in 'WAIT' state. Use acquire order + * since 'state' variable is used as the guard variable. + */ + if (__atomic_load_n(&lcore_config[worker_id].state, + __ATOMIC_ACQUIRE) != WAIT) return -EBUSY; lcore_config[worker_id].arg = arg; @@ -99,7 +103,11 @@ eal_thread_loop(void *arg __rte_unused) if (n <= 0) rte_panic("cannot read on configuration pipe\n"); - lcore_config[lcore_id].state = RUNNING; + /* Set the state to 'RUNNING'. Use release order + * since 'state' variable is used as the guard variable. + */ + __atomic_store_n(&lcore_config[lcore_id].state, RUNNING, + __ATOMIC_RELEASE); /* send ack */ n = 0; @@ -123,9 +131,14 @@ eal_thread_loop(void *arg __rte_unused) lcore_config[lcore_id].ret = ret; lcore_config[lcore_id].f = NULL; lcore_config[lcore_id].arg = NULL; - rte_wmb(); - lcore_config[lcore_id].state = WAIT; + /* Store the state with release order to ensure that + * the memory operations from the worker thread + * are completed before the state is updated. + * Use 'state' as the guard variable. + */ + __atomic_store_n(&lcore_config[lcore_id].state, WAIT, + __ATOMIC_RELEASE); } } -- 2.25.1