From patchwork Mon Aug 22 15:46:59 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jan Kiszka X-Patchwork-Id: 110948 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [140.186.70.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 913A6B6F68 for ; Tue, 23 Aug 2011 01:47:50 +1000 (EST) Received: from localhost ([::1]:38825 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QvWj1-0006Lh-Sl for incoming@patchwork.ozlabs.org; Mon, 22 Aug 2011 11:47:43 -0400 Received: from eggs.gnu.org ([140.186.70.92]:42310) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QvWio-0006AZ-Rc for qemu-devel@nongnu.org; Mon, 22 Aug 2011 11:47:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1QvWid-0001IL-Pm for qemu-devel@nongnu.org; Mon, 22 Aug 2011 11:47:30 -0400 Received: from thoth.sbs.de ([192.35.17.2]:20676) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1QvWid-0001Ek-9r for qemu-devel@nongnu.org; Mon, 22 Aug 2011 11:47:19 -0400 Received: from mail1.siemens.de (localhost [127.0.0.1]) by thoth.sbs.de (8.13.6/8.13.6) with ESMTP id p7MFkwki029989; Mon, 22 Aug 2011 17:46:58 +0200 Received: from mchn199C.mchp.siemens.de ([139.25.109.49]) by mail1.siemens.de (8.13.6/8.13.6) with ESMTP id p7MFkvks008166; Mon, 22 Aug 2011 17:46:57 +0200 Message-ID: <4E5279F3.7070103@siemens.com> Date: Mon, 22 Aug 2011 17:46:59 +0200 From: Jan Kiszka User-Agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 MIME-Version: 1.0 To: Anthony Liguori , qemu-devel X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6, seldom 2.4 (older, 4) X-Received-From: 192.35.17.2 Cc: Paolo Bonzini , Gleb Natapov Subject: [Qemu-devel] [RESEND][PATCH] Replace qemu_system_cond with VCPU stop mechanism X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org We can express the VCPU thread wakeup with the stop mechanism, saving both qemu_system_ready and the qemu_system_cond. For KVM threads, we can just enter the main loop as long as the thread is stopped. The central TCG thread is better held back before the loop as there can be side effects of the services called even when all CPUs are stopped. Creating VCPUs in stopped state will also be required for proper CPU hotplugging support. Signed-off-by: Jan Kiszka --- cpus.c | 20 ++++++-------------- 1 files changed, 6 insertions(+), 14 deletions(-) diff --git a/cpus.c b/cpus.c index b60410c..1df00b5 100644 --- a/cpus.c +++ b/cpus.c @@ -644,11 +644,9 @@ static QemuThread io_thread; static QemuThread *tcg_cpu_thread; static QemuCond *tcg_halt_cond; -static int qemu_system_ready; /* cpu creation */ static QemuCond qemu_cpu_cond; /* system init */ -static QemuCond qemu_system_cond; static QemuCond qemu_pause_cond; static QemuCond qemu_work_cond; @@ -670,7 +668,6 @@ int qemu_init_main_loop(void) } qemu_cond_init(&qemu_cpu_cond); - qemu_cond_init(&qemu_system_cond); qemu_cond_init(&qemu_pause_cond); qemu_cond_init(&qemu_work_cond); qemu_cond_init(&qemu_io_proceeded_cond); @@ -684,8 +681,7 @@ int qemu_init_main_loop(void) void qemu_main_loop_start(void) { - qemu_system_ready = 1; - qemu_cond_broadcast(&qemu_system_cond); + resume_all_vcpus(); } void run_on_cpu(CPUState *env, void (*func)(void *data), void *data) @@ -796,11 +792,6 @@ static void *qemu_kvm_cpu_thread_fn(void *arg) env->created = 1; qemu_cond_signal(&qemu_cpu_cond); - /* and wait for machine initialization */ - while (!qemu_system_ready) { - qemu_cond_wait(&qemu_system_cond, &qemu_global_mutex); - } - while (1) { if (cpu_can_run(env)) { r = kvm_cpu_exec(env); @@ -829,9 +820,9 @@ static void *qemu_tcg_cpu_thread_fn(void *arg) } qemu_cond_signal(&qemu_cpu_cond); - /* and wait for machine initialization */ - while (!qemu_system_ready) { - qemu_cond_wait(&qemu_system_cond, &qemu_global_mutex); + /* wait for initial kick-off after machine start */ + while (!first_cpu->stopped) { + qemu_cond_wait(tcg_halt_cond, &qemu_global_mutex); } while (1) { @@ -971,12 +962,12 @@ static void qemu_tcg_init_vcpu(void *_env) env->thread = g_malloc0(sizeof(QemuThread)); env->halt_cond = g_malloc0(sizeof(QemuCond)); qemu_cond_init(env->halt_cond); + tcg_halt_cond = env->halt_cond; qemu_thread_create(env->thread, qemu_tcg_cpu_thread_fn, env); while (env->created == 0) { qemu_cond_wait(&qemu_cpu_cond, &qemu_global_mutex); } tcg_cpu_thread = env->thread; - tcg_halt_cond = env->halt_cond; } else { env->thread = tcg_cpu_thread; env->halt_cond = tcg_halt_cond; @@ -1000,6 +991,7 @@ void qemu_init_vcpu(void *_env) env->nr_cores = smp_cores; env->nr_threads = smp_threads; + env->stopped = 1; if (kvm_enabled()) { qemu_kvm_start_vcpu(env); } else {