From patchwork Wed Oct 30 12:54:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yicong Yang X-Patchwork-Id: 13856494 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id E6F7DD5CCA9 for ; Wed, 30 Oct 2024 13:06:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Type: Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-ID:Date :Subject:CC:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=uYynWeIqGbf3qbAfwEFwOheYS274s3APdK2N0xWvl/8=; b=zLcaW+aZwLG9ltEsAU7PPYKEGK 4LdgGMZogAi1XHQVOct7ARrvpfjMu2mM1HvbD69bWPWQKnYf7W+fDdZEteNews+fB6lA9/qWeIYqa nLlglbmlzoTGCTB4yZE6UWoIM5/5IFWn8oUD7mw++sLjmdQL0c+cTJERxAuWJIkMMHGHf077ngCbc RHl7bFVwwiuI7w2PLEudZJ9qifq3oHAdhwnHd8nPWSq2QxNtTbb88L7ywdqrpXVg+dOefpQ2TMVUD rNZYnY15AV5QkVOaSTa4aZfwcEVkHpFbYGzZ6ecQeDfS104impIcaGAdJWkkyzdCW9QUklYPm+cYK ++S+dOfQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t68P5-00000000Puh-3KrG; Wed, 30 Oct 2024 13:06:27 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t68Dt-00000000NoE-1XvM for linux-arm-kernel@lists.infradead.org; Wed, 30 Oct 2024 12:54:58 +0000 Received: from mail.maildlp.com (unknown [172.19.162.254]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Xdn9H0YsvzyV2h; Wed, 30 Oct 2024 20:53:07 +0800 (CST) Received: from kwepemd200014.china.huawei.com (unknown [7.221.188.8]) by mail.maildlp.com (Postfix) with ESMTPS id 42D2218010F; Wed, 30 Oct 2024 20:54:46 +0800 (CST) Received: from localhost.localdomain (10.50.165.33) by kwepemd200014.china.huawei.com (7.221.188.8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.34; Wed, 30 Oct 2024 20:54:45 +0800 From: Yicong Yang To: , , , , , , , , , , , CC: , , , , , , , , , , , , Subject: [PATCH v7 2/4] arch_topology: Support SMT control for OF based system Date: Wed, 30 Oct 2024 20:54:13 +0800 Message-ID: <20241030125415.18994-3-yangyicong@huawei.com> X-Mailer: git-send-email 2.31.0 In-Reply-To: <20241030125415.18994-1-yangyicong@huawei.com> References: <20241030125415.18994-1-yangyicong@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.50.165.33] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To kwepemd200014.china.huawei.com (7.221.188.8) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241030_055453_956790_D18A1357 X-CRM114-Status: GOOD ( 17.93 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Yicong Yang On building the topology from the devicetree, we've already gotten the SMT thread number of each core. Update the largest SMT thread number and enable the SMT control by the end of topology parsing. The core's SMT control provides two interface to the users [1]: 1) enable/disable SMT by writing on/off 2) enable/disable SMT by writing thread number 1/max_thread_number If a system have more than one SMT thread number the 2) may not handle it well, since there're multiple thread numbers in the system and 2) only accept 1/max_thread_number. So issue a warning to notify the users if such system detected. [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/ABI/testing/sysfs-devices-system-cpu#n542 Signed-off-by: Yicong Yang --- drivers/base/arch_topology.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 75fcb75d5515..e2c8e6d92414 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -502,6 +503,10 @@ core_initcall(free_raw_capacity); #endif #if defined(CONFIG_ARM64) || defined(CONFIG_RISCV) + +/* Maximum SMT thread number detected used to enable the SMT control */ +static unsigned int max_smt_thread_num; + /* * This function returns the logic cpu number of the node. * There are basically three kinds of return values: @@ -561,6 +566,17 @@ static int __init parse_core(struct device_node *core, int package_id, i++; } while (1); + /* + * If max_smt_thread_num has been initialized and doesn't match + * the thread number of this entry, then the system has + * heterogeneous SMT topology. + */ + if (max_smt_thread_num && max_smt_thread_num != i) + pr_warn_once("Heterogeneous SMT topology is partly supported by SMT control\n"); + + if (max_smt_thread_num < i) + max_smt_thread_num = i; + cpu = get_cpu_for_node(core); if (cpu >= 0) { if (!leaf) { @@ -673,6 +689,14 @@ static int __init parse_socket(struct device_node *socket) if (!has_socket) ret = parse_cluster(socket, 0, -1, 0); + /* + * Notify the CPU framework of the SMT support. A thread number of 1 + * can be handled by the framework so we don't need to check + * max_smt_thread_num to see we support SMT or not. + */ + if (max_smt_thread_num) + cpu_smt_set_num_threads(max_smt_thread_num, max_smt_thread_num); + return ret; }