From patchwork Tue May 5 21:17:28 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Honnappa Nagarahalli X-Patchwork-Id: 186217 Delivered-To: patch@linaro.org Received: by 2002:a92:8d81:0:0:0:0:0 with SMTP id w1csp1514627ill; Tue, 5 May 2020 14:18:05 -0700 (PDT) X-Google-Smtp-Source: APiQypL0j+wz5XAibKTJGZGriAsQk6YLCi2Oz8R1PxtqOTXnzOEjeortQLXw4KZfrbQwMaEfEAA4 X-Received: by 2002:a50:fc82:: with SMTP id f2mr4181966edq.38.1588713485517; Tue, 05 May 2020 14:18:05 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1588713485; cv=none; d=google.com; s=arc-20160816; b=Ewd24YP6dbFfecJBcf91IcirCeAzEyUKnbU00c2CQbNVvF2zhaXYtOTV/K7Mmm3/T+ 4TkOt/hMc8/1PVfVw5BqJ5HY5RTD+qIHl0wEjUUD2mF4hWrs1pz3FbnlS2HjGWytsvN/ wEqLpplxW51JgRJjhBTawSPvbi8W/9OxdTdRczo4MSn6trhykS1fXhUt8UFfHgWQitle 0Mf7c5sLq5Q4zniel4fUB6SMH1rYxz9thGLpMt+qGsATZoHfhkZOTKBqdvcJIbXj0jiv +fq07YMFfrdvHubWKvg1+wpKaQpdlNygDFqOZ7G6UDPJ3f067MN5F9jW4jRbPpQIcp28 q9zA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:subject:references:in-reply-to :message-id:date:cc:to:from; bh=+l/pgw1qIvlppYm43vGZaGzLFbes6Q3VybRMqrSyq6M=; b=tRSdM1Fgf9rY46wHC0HubBMs7Ewsa/FUvvK9leHON/Wd0fGj5BxVLwUYcJGsbI2U6g Wa42+AkB0v2M2bGZtS2r1nzkauQKLh6ZtwvhK0TjDqsrzsdwhv3fEZOf9F2XAN08aVod YiT/DYz9NUYUtAkqOjcr83/PHcVQkrrlR2CBK9s6XSxSNMc5vikiK5P2Y0aqOROW97aK HSRR1vucEh2azriRdfcfKlCHkijKDqpNnBhlup+0h7Ki8gaUEXlRmUtt4thl5o6cgDOH HZg7aRw2EQ5bnid9Ud/RAsthmSXLDBZYRvjldE1yXJs7JgVGaskpEatu+27FlH7dUKLw qbmQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Return-Path: Received: from dpdk.org (dpdk.org. [92.243.14.124]) by mx.google.com with ESMTP id a22si1693393eju.166.2020.05.05.14.18.05; Tue, 05 May 2020 14:18:05 -0700 (PDT) Received-SPF: pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) client-ip=92.243.14.124; Authentication-Results: mx.google.com; spf=pass (google.com: domain of dev-bounces@dpdk.org designates 92.243.14.124 as permitted sender) smtp.mailfrom=dev-bounces@dpdk.org Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 8EFCE1D6E9; Tue, 5 May 2020 23:17:53 +0200 (CEST) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by dpdk.org (Postfix) with ESMTP id 96C101D6A2; Tue, 5 May 2020 23:17:51 +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 1A39F30E; Tue, 5 May 2020 14:17:51 -0700 (PDT) Received: from qc2400f-1.austin.arm.com (qc2400f-1.austin.arm.com [10.118.14.48]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 07A1A3F305; Tue, 5 May 2020 14:17:51 -0700 (PDT) From: Honnappa Nagarahalli To: dev@dpdk.org, phil.yang@arm.com, 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, stable@dpdk.org Date: Tue, 5 May 2020 16:17:28 -0500 Message-Id: <20200505211732.25291-3-honnappa.nagarahalli@arm.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200505211732.25291-1-honnappa.nagarahalli@arm.com> References: <1587659482-27133-1-git-send-email-phil.yang@arm.com> <20200505211732.25291-1-honnappa.nagarahalli@arm.com> Subject: [dpdk-dev] [PATCH v4 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" 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(-) -- 2.17.1 diff --git a/lib/librte_eal/common/rte_service.c b/lib/librte_eal/common/rte_service.c index b8c465eb9..c283408cf 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++;