From patchwork Wed Mar 30 07:47:57 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jisheng Zhang X-Patchwork-Id: 8693291 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 2A6739F39A for ; Wed, 30 Mar 2016 07:54:18 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 40130202BE for ; Wed, 30 Mar 2016 07:54:17 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5B1A52027D for ; Wed, 30 Mar 2016 07:54:16 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1alAvS-0005G1-JG; Wed, 30 Mar 2016 07:52:26 +0000 Received: from mx0a-0016f401.pphosted.com ([67.231.148.174]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1alAvP-0005E5-85 for linux-arm-kernel@lists.infradead.org; Wed, 30 Mar 2016 07:52:24 +0000 Received: from pps.filterd (m0045849.ppops.net [127.0.0.1]) by mx0a-0016f401.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u2U7koaQ005971; Wed, 30 Mar 2016 00:51:51 -0700 Received: from sc-exch04.marvell.com ([199.233.58.184]) by mx0a-0016f401.pphosted.com with ESMTP id 2206d10th7-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Wed, 30 Mar 2016 00:51:50 -0700 Received: from SC-EXCH01.marvell.com (10.93.176.81) by SC-EXCH04.marvell.com (10.93.176.84) with Microsoft SMTP Server (TLS) id 15.0.1104.5; Wed, 30 Mar 2016 00:51:49 -0700 Received: from maili.marvell.com (10.93.176.43) by SC-EXCH01.marvell.com (10.93.176.81) with Microsoft SMTP Server id 15.0.1104.5 via Frontend Transport; Wed, 30 Mar 2016 00:51:49 -0700 Received: from xhacker.marvell.com (unknown [10.37.135.134]) by maili.marvell.com (Postfix) with ESMTP id BECF53F7040; Wed, 30 Mar 2016 00:51:48 -0700 (PDT) From: Jisheng Zhang To: , , Subject: [PATCH v2] ARM: cpuidle: make arm_cpuidle_suspend() a bit more efficient Date: Wed, 30 Mar 2016 15:47:57 +0800 Message-ID: <1459324077-7116-1-git-send-email-jszhang@marvell.com> X-Mailer: git-send-email 2.8.0.rc3 MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-03-30_04:, , signatures=0 X-Proofpoint-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1601100000 definitions=main-1603300114 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160330_005223_309850_E36D9B92 X-CRM114-Status: GOOD ( 15.85 ) X-Spam-Score: -2.6 (--) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jisheng Zhang , linux-arm-kernel@lists.infradead.org, lina.iyer@linaro.org, linux-kernel@vger.kernel.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-5.2 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Currently, we check cpuidle_ops.suspend every time when entering a low-power idle state. But this check could be avoided in this hot path by moving it into arm_cpuidle_read_ops() to reduce arm_cpuidle_suspend overhead a bit. Signed-off-by: Jisheng Zhang --- Since v1: - drop patch1, I.E "ARM: cpuidle: fix !cpuidle_ops[cpu].init case during init", because there may be platforms which doesn't need the init member at all. - adopt Daniel's suggestion to move the cpuidle_ops.suspend check to arm_cpuidle_read_ops(). arch/arm/kernel/cpuidle.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/arch/arm/kernel/cpuidle.c b/arch/arm/kernel/cpuidle.c index 703926e..e63388e 100644 --- a/arch/arm/kernel/cpuidle.c +++ b/arch/arm/kernel/cpuidle.c @@ -47,18 +47,13 @@ int arm_cpuidle_simple_enter(struct cpuidle_device *dev, * This function calls the underlying arch specific low level PM code as * registered at the init time. * - * Returns -EOPNOTSUPP if no suspend callback is defined, the result of the - * callback otherwise. + * Returns the result of the suspend callback. */ int arm_cpuidle_suspend(int index) { - int ret = -EOPNOTSUPP; int cpu = smp_processor_id(); - if (cpuidle_ops[cpu].suspend) - ret = cpuidle_ops[cpu].suspend(index); - - return ret; + return cpuidle_ops[cpu].suspend(index); } /** @@ -92,7 +87,8 @@ static struct cpuidle_ops *__init arm_cpuidle_get_ops(const char *method) * process. * * Return 0 on sucess, -ENOENT if no 'enable-method' is defined, -EOPNOTSUPP if - * no cpuidle_ops is registered for the 'enable-method'. + * no cpuidle_ops is registered for the 'enable-method', or if no suspend + * callback is defined. */ static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu) { @@ -110,6 +106,12 @@ static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu) return -EOPNOTSUPP; } + if (!ops->suspend) { + pr_warn("cpuidle_ops '%s': no suspend callback\n", + enable_method); + return -EOPNOTSUPP; + } + cpuidle_ops[cpu] = *ops; /* structure copy */ pr_notice("cpuidle: enable-method property '%s'" @@ -129,7 +131,8 @@ static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu) * Returns: * 0 on success, * -ENODEV if it fails to find the cpu node in the device tree, - * -EOPNOTSUPP if it does not find a registered cpuidle_ops for this cpu, + * -EOPNOTSUPP if it does not find a registered and valid cpuidle_ops for + * this cpu, * -ENOENT if it fails to find an 'enable-method' property, * -ENXIO if the HW reports a failure or a misconfiguration, * -ENOMEM if the HW report an memory allocation failure