From patchwork Wed Feb 24 21:20:15 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honnappa Nagarahalli X-Patchwork-Id: 88178 X-Patchwork-Delegate: david.marchand@redhat.com Return-Path: X-Original-To: patchwork@inbox.dpdk.org Delivered-To: patchwork@inbox.dpdk.org Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id E86F4A034F; Wed, 24 Feb 2021 22:20:46 +0100 (CET) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 4407C16075A; Wed, 24 Feb 2021 22:20:45 +0100 (CET) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by mails.dpdk.org (Postfix) with ESMTP id 5EECD160758 for ; Wed, 24 Feb 2021 22:20:43 +0100 (CET) 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 D57C7101E; Wed, 24 Feb 2021 13:20:42 -0800 (PST) Received: from qc2400f-1.austin.arm.com (qc2400f-1.austin.arm.com [10.118.12.44]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C0F3D3F73D; Wed, 24 Feb 2021 13:20:42 -0800 (PST) From: Honnappa Nagarahalli To: Bruce Richardson , Dmitry Kozlyuk , Narcisa Ana Maria Vasile , Dmitry Malloy , Pallavi Kadam Cc: dev@dpdk.org, honnappa.nagarahalli@arm.com, ruifeng.wang@arm.com, feifei.wang@arm.com, nd@arm.com Date: Wed, 24 Feb 2021 15:20:15 -0600 Message-Id: <20210224212018.17576-3-honnappa.nagarahalli@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20210224212018.17576-1-honnappa.nagarahalli@arm.com> References: <20210224212018.17576-1-honnappa.nagarahalli@arm.com> Subject: [dpdk-dev] [RFC 2/5] eal: ensure memory operations are visible to worker 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 before the call to rte_eal_remote_launch are visible to the worker thread. Signed-off-by: Honnappa Nagarahalli Reviewed-by: Ola Liljedahl --- lib/librte_eal/freebsd/eal_thread.c | 19 +++++++++++++++---- lib/librte_eal/linux/eal_thread.c | 19 +++++++++++++++---- lib/librte_eal/windows/eal_thread.c | 19 +++++++++++++++---- 3 files changed, 45 insertions(+), 12 deletions(-) diff --git a/lib/librte_eal/freebsd/eal_thread.c b/lib/librte_eal/freebsd/eal_thread.c index bbc3a8e98..17b8f3996 100644 --- a/lib/librte_eal/freebsd/eal_thread.c +++ b/lib/librte_eal/freebsd/eal_thread.c @@ -42,8 +42,12 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned worker_id) if (lcore_config[worker_id].state != WAIT) goto finish; - lcore_config[worker_id].f = f; 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. + */ + __atomic_store_n(&lcore_config[worker_id].f, f, __ATOMIC_RELEASE); /* send message */ n = 0; @@ -100,6 +104,7 @@ eal_thread_loop(__rte_unused void *arg) /* read on our pipe to get commands */ while (1) { + lcore_function_t *f; void *fct_arg; /* wait command */ @@ -119,12 +124,18 @@ eal_thread_loop(__rte_unused void *arg) if (n < 0) rte_panic("cannot write on configuration pipe\n"); - if (lcore_config[lcore_id].f == NULL) - rte_panic("NULL function pointer\n"); + /* Load 'f' with acquire order to ensure that + * the memory operations from the main thread + * are accessed only after update to 'f' is visible. + * Wait till the update to 'f' is visible to the worker. + */ + while ((f = __atomic_load_n(&lcore_config[lcore_id].f, + __ATOMIC_ACQUIRE)) == NULL) + rte_pause(); /* call the function and store the return value */ fct_arg = lcore_config[lcore_id].arg; - ret = lcore_config[lcore_id].f(fct_arg); + ret = f(fct_arg); lcore_config[lcore_id].ret = ret; lcore_config[lcore_id].f = NULL; lcore_config[lcore_id].arg = NULL; diff --git a/lib/librte_eal/linux/eal_thread.c b/lib/librte_eal/linux/eal_thread.c index 8f3c0dafd..a0a009104 100644 --- a/lib/librte_eal/linux/eal_thread.c +++ b/lib/librte_eal/linux/eal_thread.c @@ -42,8 +42,12 @@ rte_eal_remote_launch(int (*f)(void *), void *arg, unsigned int worker_id) if (lcore_config[worker_id].state != WAIT) goto finish; - lcore_config[worker_id].f = f; 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. + */ + __atomic_store_n(&lcore_config[worker_id].f, f, __ATOMIC_RELEASE); /* send message */ n = 0; @@ -100,6 +104,7 @@ eal_thread_loop(__rte_unused void *arg) /* read on our pipe to get commands */ while (1) { + lcore_function_t *f; void *fct_arg; /* wait command */ @@ -119,12 +124,18 @@ eal_thread_loop(__rte_unused void *arg) if (n < 0) rte_panic("cannot write on configuration pipe\n"); - if (lcore_config[lcore_id].f == NULL) - rte_panic("NULL function pointer\n"); + /* Load 'f' with acquire order to ensure that + * the memory operations from the main thread + * are accessed only after update to 'f' is visible. + * Wait till the update to 'f' is visible to the worker. + */ + while ((f = __atomic_load_n(&lcore_config[lcore_id].f, + __ATOMIC_ACQUIRE)) == NULL) + rte_pause(); /* call the function and store the return value */ fct_arg = lcore_config[lcore_id].arg; - ret = lcore_config[lcore_id].f(fct_arg); + ret = f(fct_arg); lcore_config[lcore_id].ret = ret; lcore_config[lcore_id].f = NULL; lcore_config[lcore_id].arg = NULL; diff --git a/lib/librte_eal/windows/eal_thread.c b/lib/librte_eal/windows/eal_thread.c index b69672fe0..7a9277c51 100644 --- a/lib/librte_eal/windows/eal_thread.c +++ b/lib/librte_eal/windows/eal_thread.c @@ -32,8 +32,12 @@ rte_eal_remote_launch(lcore_function_t *f, void *arg, unsigned int worker_id) if (lcore_config[worker_id].state != WAIT) return -EBUSY; - lcore_config[worker_id].f = f; 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. + */ + __atomic_store_n(&lcore_config[worker_id].f, f, __ATOMIC_RELEASE); /* send message */ n = 0; @@ -84,6 +88,7 @@ eal_thread_loop(void *arg __rte_unused) /* read on our pipe to get commands */ while (1) { + lcore_function_t *f; void *fct_arg; /* wait command */ @@ -103,12 +108,18 @@ eal_thread_loop(void *arg __rte_unused) if (n < 0) rte_panic("cannot write on configuration pipe\n"); - if (lcore_config[lcore_id].f == NULL) - rte_panic("NULL function pointer\n"); + /* Load 'f' with acquire order to ensure that + * the memory operations from the main thread + * are accessed only after update to 'f' is visible. + * Wait till the update to 'f' is visible to the worker. + */ + while ((f = __atomic_load_n(&lcore_config[lcore_id].f, + __ATOMIC_ACQUIRE)) == NULL) + rte_pause(); /* call the function and store the return value */ fct_arg = lcore_config[lcore_id].arg; - ret = lcore_config[lcore_id].f(fct_arg); + ret = f(fct_arg); lcore_config[lcore_id].ret = ret; lcore_config[lcore_id].f = NULL; lcore_config[lcore_id].arg = NULL;