From patchwork Thu Feb 13 11:32:35 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roger Pau Monne X-Patchwork-Id: 11380181 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 5A1D71805 for ; Thu, 13 Feb 2020 11:34:14 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 36AC62073C for ; Thu, 13 Feb 2020 11:34:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="MmHWoAXr" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 36AC62073C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=citrix.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1j2CkB-0006Xb-Sl; Thu, 13 Feb 2020 11:33:19 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1j2CkA-0006XU-OI for xen-devel@lists.xenproject.org; Thu, 13 Feb 2020 11:33:18 +0000 X-Inumbo-ID: a1070064-4e54-11ea-bc8e-bc764e2007e4 Received: from esa1.hc3370-68.iphmx.com (unknown [216.71.145.142]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id a1070064-4e54-11ea-bc8e-bc764e2007e4; Thu, 13 Feb 2020 11:33:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1581593598; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=f0i7TB3UZJwx/eyDuGora1qwgmdeB3oysqK5f0G475M=; b=MmHWoAXrCypjKInnie2ajtJiGuyxFrYxawNbudeis3oEt5LTqjRh//k8 H8uS5ATcMZxhmWCkMXjzhxJi6mj2nhiD6qyQ+CUJ/GndgaYANsaADWcKy H9kcXKHXwnYTq/1IYKhIxlcITXpnqdPL6CHIvyKdpwzg+kkdNzVNqIphc E=; Authentication-Results: esa1.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none; spf=None smtp.pra=roger.pau@citrix.com; spf=Pass smtp.mailfrom=roger.pau@citrix.com; spf=None smtp.helo=postmaster@mail.citrix.com Received-SPF: None (esa1.hc3370-68.iphmx.com: no sender authenticity information available from domain of roger.pau@citrix.com) identity=pra; client-ip=162.221.158.21; receiver=esa1.hc3370-68.iphmx.com; envelope-from="roger.pau@citrix.com"; x-sender="roger.pau@citrix.com"; x-conformance=sidf_compatible Received-SPF: Pass (esa1.hc3370-68.iphmx.com: domain of roger.pau@citrix.com designates 162.221.158.21 as permitted sender) identity=mailfrom; client-ip=162.221.158.21; receiver=esa1.hc3370-68.iphmx.com; envelope-from="roger.pau@citrix.com"; x-sender="roger.pau@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ip4:168.245.78.127 ~all" Received-SPF: None (esa1.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa1.hc3370-68.iphmx.com; envelope-from="roger.pau@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: ue6o12idE16AFHiBq8p8GfgI35TMs5LT6GfyQEXkzpR57+N9K+IC/VRxhQhFqBpoRmRRucLAa3 bjLVAEMpLVEAX9gbptGfqJwwwGoI+fP2u1rDr9/DfRJJyNndeyim4GfrQQ6q5LVEbfy/tK/2pz 8Y2W8VRfnniZTMLCtaHCzE+2s0dNfT2n3nLzUiFi1yp5cn+SGRJAes2Ck5JqrS+44b3JsIIdIw uacpnb5pgXNaTKPnpMD5eWHgj4r/ImI9O6OgGbG8M9fjWGMFLK0xN7AQA1RhmW/Tb9W/0xlJtx bIc= X-SBRS: 2.7 X-MesageID: 12566477 X-Ironport-Server: esa1.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.70,436,1574139600"; d="scan'208";a="12566477" From: Roger Pau Monne To: Date: Thu, 13 Feb 2020 12:32:35 +0100 Message-ID: <20200213113237.58795-1-roger.pau@citrix.com> X-Mailer: git-send-email 2.25.0 MIME-Version: 1.0 Subject: [Xen-devel] [PATCH 0/2] smp: convert cpu_add_remove_lock int a rw lock X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Julien Grall , Wei Liu , Konrad Rzeszutek Wilk , George Dunlap , Andrew Cooper , Ian Jackson , Jan Beulich , Roger Pau Monne Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Hello, The main aim of this series is to reduce the pressure around cpu_add_remove_lock by converting it into a rw lock. Most users of the lock want to take it in read mode, as they only care about the maps not changing. Patch #2 makes the writers take the lock in blocking mode, this is mainly done to reduce the failure of the CPU plug/unplug operations, since the lock is more contended now and trylock can easily fail if there are readers. Thanks, Roger. Roger Pau Monne (2): smp: convert the cpu maps lock into a rw lock smp: convert cpu_hotplug_begin into a blocking lock acquisition xen/arch/x86/smpboot.c | 3 +-- xen/common/cpu.c | 29 ++++++++++++++++++----------- xen/include/xen/cpu.h | 13 +++---------- 3 files changed, 22 insertions(+), 23 deletions(-)