From patchwork Wed Jul 6 06:15:55 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jisheng Zhang X-Patchwork-Id: 9215475 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id D056960752 for ; Wed, 6 Jul 2016 06:21:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C051F286EE for ; Wed, 6 Jul 2016 06:21:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id B518E286F0; Wed, 6 Jul 2016 06:21:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 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.wl.linuxfoundation.org (Postfix) with ESMTPS id 6A48B286EE for ; Wed, 6 Jul 2016 06:21:54 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.85_2 #1 (Red Hat Linux)) id 1bKgCP-0005XZ-07; Wed, 06 Jul 2016 06:20:41 +0000 Received: from mx0b-0016f401.pphosted.com ([67.231.156.173]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1bKgC4-00046q-BR for linux-arm-kernel@lists.infradead.org; Wed, 06 Jul 2016 06:20:21 +0000 Received: from pps.filterd (m0045851.ppops.net [127.0.0.1]) by mx0b-0016f401.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id u666HkH3027874; Tue, 5 Jul 2016 23:19:49 -0700 Received: from sc-exch01.marvell.com ([199.233.58.181]) by mx0b-0016f401.pphosted.com with ESMTP id 23xd4fy8g0-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT); Tue, 05 Jul 2016 23:19:49 -0700 Received: from SC-EXCH01.marvell.com (10.93.176.81) by SC-EXCH01.marvell.com (10.93.176.81) with Microsoft SMTP Server (TLS) id 15.0.1104.5; Tue, 5 Jul 2016 23:19:47 -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; Tue, 5 Jul 2016 23:19:47 -0700 Received: from xhacker.marvell.com (shsp-lt4.marvell.com [10.37.130.124]) by maili.marvell.com (Postfix) with ESMTP id 72EFB3F703F; Tue, 5 Jul 2016 23:19:46 -0700 (PDT) From: Jisheng Zhang To: , , , Subject: [PATCH v4 2/2] ARM: cpuidle: make arm_cpuidle_suspend() a bit more efficient Date: Wed, 6 Jul 2016 14:15:55 +0800 Message-ID: <1467785755-3488-3-git-send-email-jszhang@marvell.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1467785755-3488-1-git-send-email-jszhang@marvell.com> References: <1467785755-3488-1-git-send-email-jszhang@marvell.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:, , definitions=2016-07-06_03:, , 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=8.0.1-1604210000 definitions=main-1607060057 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20160705_232020_537628_2990A294 X-CRM114-Status: GOOD ( 12.64 ) 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-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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 Acked-by: Daniel Lezcano --- arch/arm/kernel/cpuidle.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) diff --git a/arch/arm/kernel/cpuidle.c b/arch/arm/kernel/cpuidle.c index 2129b29..7dccc96 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); } /** @@ -92,8 +87,8 @@ static const 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', or if no init callback - * is defined. + * no cpuidle_ops is registered for the 'enable-method', or if either init or + * suspend callback isn't defined. */ static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu) { @@ -111,8 +106,8 @@ static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu) return -EOPNOTSUPP; } - if (!ops->init) { - pr_warn("cpuidle_ops '%s': no init callback\n", + if (!ops->init || !ops->suspend) { + pr_warn("cpuidle_ops '%s': no init or suspend callback\n", enable_method); return -EOPNOTSUPP; }