From patchwork Wed Nov 6 09:08:49 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhenzhong Duan X-Patchwork-Id: 11229693 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6496C112B for ; Wed, 6 Nov 2019 09:11:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 413622178F for ; Wed, 6 Nov 2019 09:11:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="L6Aemdo9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731528AbfKFJLn (ORCPT ); Wed, 6 Nov 2019 04:11:43 -0500 Received: from userp2130.oracle.com ([156.151.31.86]:45742 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727041AbfKFJLm (ORCPT ); Wed, 6 Nov 2019 04:11:42 -0500 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xA698wYd116234; Wed, 6 Nov 2019 09:11:25 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2019-08-05; bh=EPKzfVRRWTGlG40d7rhnldMOWGwhBLJaJGkHe+80yiw=; b=L6Aemdo9fhglASfZz2I71e0bQ6RJFLKi23q2FFx8QEXB8h+shi2JmTu2aijSZBJNxag5 FL8ciWvzZK2/qc2IWw0Gswr9Z9wm931bc3WonurMT9rl0zOVNf0wkNJ9vVdU2kzB1Ecj 2gBv+Hkdq0t1s8Nn9q3SJLlsD3ownbR7HuQ00IGCPxhSa3Msgdmo3ioVM5RRVAefKNAe ST6/7q/FNwlpqE7Pe0zG8o9tJpdEm1kAcS/VpP4JzzcGQ0RztuB5CXkZ4gQt+e709AWQ OhmCYy5JrS56J8x+WBsYni3NYzpoGMnXV6uOtaccfnEPpRm865Yj1jwzOurwWnY7PrY0 Mw== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 2w117u4h0q-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 06 Nov 2019 09:11:25 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id xA6986Ah077631; Wed, 6 Nov 2019 09:09:24 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3030.oracle.com with ESMTP id 2w35pqk36k-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 06 Nov 2019 09:09:24 +0000 Received: from abhmp0009.oracle.com (abhmp0009.oracle.com [141.146.116.15]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id xA699N3M001024; Wed, 6 Nov 2019 09:09:23 GMT Received: from z2.cn.oracle.com (/10.182.71.218) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 06 Nov 2019 01:09:23 -0800 From: Zhenzhong Duan To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: pbonzini@redhat.com, rkrcmar@redhat.com, rafael.j.wysocki@intel.com, joao.m.martins@oracle.com, mtosatti@redhat.com, Zhenzhong Duan Subject: [PATCH v2 1/4] cpuidle-haltpoll: ensure grow start value is nonzero Date: Wed, 6 Nov 2019 17:08:49 +0800 Message-Id: <1573031332-2121-2-git-send-email-zhenzhong.duan@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1573031332-2121-1-git-send-email-zhenzhong.duan@oracle.com> References: <1573031332-2121-1-git-send-email-zhenzhong.duan@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9432 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=854 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1911060096 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9432 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=932 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1908290000 definitions=main-1911060096 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org dev->poll_limit_ns could be zeroed in certain cases (e.g. by guest_halt_poll_ns = 0). If guest_halt_poll_grow_start is zero, dev->poll_limit_ns will never be bigger than zero. Use param callback to avoid writing zero to guest_halt_poll_grow_start. Signed-off-by: Zhenzhong Duan --- drivers/cpuidle/governors/haltpoll.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c index 7a703d2..660859d 100644 --- a/drivers/cpuidle/governors/haltpoll.c +++ b/drivers/cpuidle/governors/haltpoll.c @@ -20,6 +20,26 @@ #include #include +static int grow_start_set(const char *val, const struct kernel_param *kp) +{ + int ret; + unsigned int n; + + if (!val) + return -EINVAL; + + ret = kstrtouint(val, 0, &n); + if (ret || !n) + return -EINVAL; + + return param_set_uint(val, kp); +} + +static const struct kernel_param_ops grow_start_ops = { + .set = grow_start_set, + .get = param_get_uint, +}; + static unsigned int guest_halt_poll_ns __read_mostly = 200000; module_param(guest_halt_poll_ns, uint, 0644); @@ -33,7 +53,7 @@ /* value in us to start growing per-cpu halt_poll_ns */ static unsigned int guest_halt_poll_grow_start __read_mostly = 50000; -module_param(guest_halt_poll_grow_start, uint, 0644); +module_param_cb(guest_halt_poll_grow_start, &grow_start_ops, &guest_halt_poll_grow_start, 0644); /* allow shrinking guest halt poll */ static bool guest_halt_poll_allow_shrink __read_mostly = true;