From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 38619A034F; Wed, 6 May 2020 12:26:00 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id ED6D71D907; Wed, 6 May 2020 12:25:57 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id BF5F81D8FF; Wed, 6 May 2020 12:25:56 +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 47FD130E; Wed, 6 May 2020 03:25:56 -0700 (PDT) Received: from phil-VirtualBox.shanghai.arm.com (phil-VirtualBox.shanghai.arm.com [10.169.108.145]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id DCFF93F71F; Wed, 6 May 2020 03:25:52 -0700 (PDT) From: Phil Yang To: dev@dpdk.org, harry.van.haaren@intel.com Cc: thomas@monjalon.net, david.marchand@redhat.com, konstantin.ananyev@intel.com, jerinj@marvell.com, hemant.agrawal@nxp.com, gage.eads@intel.com, bruce.richardson@intel.com, Honnappa.Nagarahalli@arm.com, nd@arm.com, Honnappa Nagarahalli , stable@dpdk.org Date: Wed, 6 May 2020 18:24:39 +0800 Message-Id: <1588760683-11027-3-git-send-email-phil.yang@arm.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1588760683-11027-1-git-send-email-phil.yang@arm.com> References: <20200505211732.25291-1-honnappa.nagarahalli@arm.com> <1588760683-11027-1-git-send-email-phil.yang@arm.com> Subject: [dpdk-dev] [PATCH v5 2/6] service: fix identification of service running on other lcore X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 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" From: Honnappa Nagarahalli The logic to identify if the MT unsafe service is running on another core can return -EBUSY spuriously. In such cases, running the service becomes costlier than using atomic operations. Assume that the application passes the right parameters and reduce the number of instructions for all cases. Cc: stable@dpdk.org Fixes: 8d39d3e237c2 ("service: fix race in service on app lcore function") Signed-off-by: Honnappa Nagarahalli Reviewed-by: Phil Yang Acked-by: Harry van Haaren --- lib/librte_eal/common/rte_service.c | 26 ++++++++------------------ 1 file changed, 8 insertions(+), 18 deletions(-) diff --git a/lib/librte_eal/common/rte_service.c b/lib/librte_eal/common/rte_service.c index b8c465e..c283408 100644 --- a/lib/librte_eal/common/rte_service.c +++ b/lib/librte_eal/common/rte_service.c @@ -360,7 +360,7 @@ rte_service_runner_do_callback(struct rte_service_spec_impl *s, /* Expects the service 's' is valid. */ static int32_t service_run(uint32_t i, struct core_state *cs, uint64_t service_mask, - struct rte_service_spec_impl *s) + struct rte_service_spec_impl *s, uint32_t serialize_mt_unsafe) { if (!s) return -EINVAL; @@ -374,7 +374,7 @@ service_run(uint32_t i, struct core_state *cs, uint64_t service_mask, cs->service_active_on_lcore[i] = 1; - if (service_mt_safe(s) == 0) { + if ((service_mt_safe(s) == 0) && (serialize_mt_unsafe == 1)) { if (!rte_atomic32_cmpset((uint32_t *)&s->execute_lock, 0, 1)) return -EBUSY; @@ -412,24 +412,14 @@ rte_service_run_iter_on_app_lcore(uint32_t id, uint32_t serialize_mt_unsafe) SERVICE_VALID_GET_OR_ERR_RET(id, s, -EINVAL); - /* Atomically add this core to the mapped cores first, then examine if - * we can run the service. This avoids a race condition between - * checking the value, and atomically adding to the mapped count. + /* Increment num_mapped_cores to reflect that this core is + * now mapped capable of running the service. */ - if (serialize_mt_unsafe) - rte_atomic32_inc(&s->num_mapped_cores); + rte_atomic32_inc(&s->num_mapped_cores); - if (service_mt_safe(s) == 0 && - rte_atomic32_read(&s->num_mapped_cores) > 1) { - if (serialize_mt_unsafe) - rte_atomic32_dec(&s->num_mapped_cores); - return -EBUSY; - } - - int ret = service_run(id, cs, UINT64_MAX, s); + int ret = service_run(id, cs, UINT64_MAX, s, serialize_mt_unsafe); - if (serialize_mt_unsafe) - rte_atomic32_dec(&s->num_mapped_cores); + rte_atomic32_dec(&s->num_mapped_cores); return ret; } @@ -449,7 +439,7 @@ rte_service_runner_func(void *arg) if (!service_valid(i)) continue; /* return value ignored as no change to code flow */ - service_run(i, cs, service_mask, service_get(i)); + service_run(i, cs, service_mask, service_get(i), 1); } cs->loops++; -- 2.7.4