From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67D90C33CB8 for ; Wed, 15 Jan 2020 04:15:41 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 1C4092467A for ; Wed, 15 Jan 2020 04:15:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="B3aHJ6p3"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="J/naHHta" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1C4092467A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=orgqdn84o0JU+hX1zMfz4Q1JUv/bYuzaNkhwWlsPsOU=; b=B3aHJ6p3uzzlVC hBIKnOLS3nDH2+vPj9ZCDUC+YN8F/TibCAH0sIDdn5+I8gLrEyfoHaeNwPsSY8Y+2I46ZFA+agSGj Y0nZ3TJW55T050DFzBBuQQmvKSMkjsPuiZyh8Utq2BwO5pmW45N2Rr3WoHZErdmu+9La8/XOOXMxo tZtbj5TFOzZoZJ+oFKe2zaZ+XlcFs97N1WFAi08NzQr1HKl09iSbv8838pjggahgzXQV/CNgCfjWU 6vJOxeacVaiT6AN79PvjxnYsY36WCeaaRDW6ZnckORQSxKkl199pMVfiMyShv2FZWD5jrZbwaIND6 PDNLwKSwcvJLVC8dHqvQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ira5k-0007Fi-4Y; Wed, 15 Jan 2020 04:15:40 +0000 Received: from userp2120.oracle.com ([156.151.31.85]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ira5E-0006Hv-0U for linux-arm-kernel@lists.infradead.org; Wed, 15 Jan 2020 04:15:11 +0000 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00F4D5v0016259; Wed, 15 Jan 2020 04:14:29 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 : mime-version : content-transfer-encoding; s=corp-2019-08-05; bh=j0kP4cgw11+0V8n3FBX8OuaGrItpmdeWbr2wr5B5cac=; b=J/naHHtaVFM+ovw2tXeK59mOLuCB3EuwQTtRT/fBmG+dlifM8qvNBe3wFNPwEZ3gd2P9 inPDRZ0MnIXf9c/FxjtnSjxfEcnXb5evtyCaOXu1ZTJ50Uq/5EmyXC2pMhc70IuydgMN z/K5hwYnniX6FccnnaTd1HqcVm2TUeVsM+AqPomaA/xnmIcE5OcLai13A7wwLJmmZQO+ If+xyscqebBCHUGkkKqKXNvHWxnzEM/2+8WV8sPJ3e9/VkLNsapaOgHtOimNuApfP09w tf9J4UyF/xL4X6MqFFDOm/2so06C2VoViVJNJfEQ797+FUPcFnCRE5b65McVuPNMIO21 cQ== Received: from aserp3020.oracle.com (aserp3020.oracle.com [141.146.126.70]) by userp2120.oracle.com with ESMTP id 2xf73yhyqv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 15 Jan 2020 04:14:29 +0000 Received: from pps.filterd (aserp3020.oracle.com [127.0.0.1]) by aserp3020.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00F4EKql095387; Wed, 15 Jan 2020 04:14:28 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3020.oracle.com with ESMTP id 2xh315dbs4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 15 Jan 2020 04:14:28 +0000 Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 00F4D44V015872; Wed, 15 Jan 2020 04:13:04 GMT Received: from neelam.us.oracle.com (/10.152.128.16) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Tue, 14 Jan 2020 20:13:04 -0800 From: Alex Kogan To: linux@armlinux.org.uk, peterz@infradead.org, mingo@redhat.com, will.deacon@arm.com, arnd@arndb.de, longman@redhat.com, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, bp@alien8.de, hpa@zytor.com, x86@kernel.org, guohanjun@huawei.com, jglauber@marvell.com Subject: [PATCH v9 4/5] locking/qspinlock: Introduce starvation avoidance into CNA Date: Tue, 14 Jan 2020 22:59:19 -0500 Message-Id: <20200115035920.54451-5-alex.kogan@oracle.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20200115035920.54451-1-alex.kogan@oracle.com> References: <20200115035920.54451-1-alex.kogan@oracle.com> MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9500 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001150033 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9500 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=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001150033 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200114_201508_148091_BF91401C X-CRM114-Status: GOOD ( 25.84 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: alex.kogan@oracle.com, dave.dice@oracle.com, steven.sistare@oracle.com, daniel.m.jordan@oracle.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Keep track of the number of intra-node lock handoffs, and force inter-node handoff once this number reaches a preset threshold. The default value for the threshold can be overridden with the new kernel boot command-line option "numa_spinlock_threshold". Signed-off-by: Alex Kogan Reviewed-by: Steve Sistare Reviewed-by: Waiman Long --- .../admin-guide/kernel-parameters.txt | 8 ++++ kernel/locking/qspinlock.c | 3 ++ kernel/locking/qspinlock_cna.h | 41 ++++++++++++++++++- 3 files changed, 51 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b68cb80e477f..30d79819a3b0 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -3200,6 +3200,14 @@ Not specifying this option is equivalent to numa_spinlock=auto. + numa_spinlock_threshold= [NUMA, PV_OPS] + Set the threshold for the number of intra-node + lock hand-offs before the NUMA-aware spinlock + is forced to be passed to a thread on another NUMA node. + Valid values are in the [0..31] range. Smaller values + result in a more fair, but less performant spinlock, and + vice versa. The default value is 16. + cpu0_hotplug [X86] Turn on CPU0 hotplug feature when CONFIG_BOOTPARAM_HOTPLUG_CPU0 is off. Some features depend on CPU0. Known dependencies are: diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 609980a53841..e382d8946ccc 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -597,6 +597,9 @@ EXPORT_SYMBOL(queued_spin_lock_slowpath); #if !defined(_GEN_CNA_LOCK_SLOWPATH) && defined(CONFIG_NUMA_AWARE_SPINLOCKS) #define _GEN_CNA_LOCK_SLOWPATH +#undef pv_init_node +#define pv_init_node cna_init_node + #undef pv_wait_head_or_lock #define pv_wait_head_or_lock cna_pre_scan diff --git a/kernel/locking/qspinlock_cna.h b/kernel/locking/qspinlock_cna.h index 8000231f3d51..a2b65f87e6f8 100644 --- a/kernel/locking/qspinlock_cna.h +++ b/kernel/locking/qspinlock_cna.h @@ -51,13 +51,25 @@ struct cna_node { int numa_node; u32 encoded_tail; u32 pre_scan_result; /* encoded tail or enum val */ + u32 intra_count; }; enum { LOCAL_WAITER_FOUND = 2, /* 0 and 1 are reserved for @locked */ + FLUSH_SECONDARY_QUEUE = 3, MIN_ENCODED_TAIL }; +/* + * Controls the threshold for the number of intra-node lock hand-offs before + * the NUMA-aware variant of spinlock is forced to be passed to a thread on + * another NUMA node. By default, the chosen value provides reasonable + * long-term fairness without sacrificing performance compared to a lock + * that does not have any fairness guarantees. The default setting can + * be changed with the "numa_spinlock_threshold" boot option. + */ +unsigned int intra_node_handoff_threshold __ro_after_init = 1 << 16; + static void __init cna_init_nodes_per_cpu(unsigned int cpu) { struct mcs_spinlock *base = per_cpu_ptr(&qnodes[0].mcs, cpu); @@ -97,6 +109,11 @@ static int __init cna_init_nodes(void) } early_initcall(cna_init_nodes); +static __always_inline void cna_init_node(struct mcs_spinlock *node) +{ + ((struct cna_node *)node)->intra_count = 0; +} + /* this function is called only when the primary queue is empty */ static inline bool cna_try_change_tail(struct qspinlock *lock, u32 val, struct mcs_spinlock *node) @@ -232,7 +249,9 @@ __always_inline u32 cna_pre_scan(struct qspinlock *lock, { struct cna_node *cn = (struct cna_node *)node; - cn->pre_scan_result = cna_scan_main_queue(node, node); + cn->pre_scan_result = + cn->intra_count == intra_node_handoff_threshold ? + FLUSH_SECONDARY_QUEUE : cna_scan_main_queue(node, node); return 0; } @@ -262,6 +281,9 @@ static inline void cna_pass_lock(struct mcs_spinlock *node, * if we acquired the MCS lock when its queue was empty */ val = node->locked ? node->locked : 1; + /* inc @intra_count if the secondary queue is not empty */ + ((struct cna_node *)next_holder)->intra_count = + cn->intra_count + (node->locked > 1); } else if (node->locked > 1) { /* if secondary queue is not empty */ /* next holder will be the first node in the secondary queue */ tail_2nd = decode_tail(node->locked); @@ -316,3 +338,20 @@ void __init cna_configure_spin_lock_slowpath(void) pr_info("Enabling CNA spinlock\n"); } } + +static int __init numa_spinlock_threshold_setup(char *str) +{ + int new_threshold_param; + + if (get_option(&str, &new_threshold_param)) { + /* valid value is between 0 and 31 */ + if (new_threshold_param < 0 || new_threshold_param > 31) + return 0; + + intra_node_handoff_threshold = 1 << new_threshold_param; + return 1; + } + + return 0; +} +__setup("numa_spinlock_threshold=", numa_spinlock_threshold_setup); -- 2.21.0 (Apple Git-122.2) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel