From patchwork Wed Mar 6 11:55:28 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 10841055 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C7FF0922 for ; Wed, 6 Mar 2019 12:02:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B1C8F2D301 for ; Wed, 6 Mar 2019 12:02:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id A5F682D73D; Wed, 6 Mar 2019 12:02:50 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 499442D301 for ; Wed, 6 Mar 2019 12:02:50 +0000 (UTC) Received: from localhost ([127.0.0.1]:60171 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h1VG5-0005V1-Ib for patchwork-qemu-devel@patchwork.kernel.org; Wed, 06 Mar 2019 07:02:49 -0500 Received: from eggs.gnu.org ([209.51.188.92]:46263) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1h1V9V-00006D-68 for qemu-devel@nongnu.org; Wed, 06 Mar 2019 06:56:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1h1V9N-0005nd-0X for qemu-devel@nongnu.org; Wed, 06 Mar 2019 06:55:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:33428) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1h1V9K-0005lj-TK for qemu-devel@nongnu.org; Wed, 06 Mar 2019 06:55:52 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9B99688313 for ; Wed, 6 Mar 2019 11:55:49 +0000 (UTC) Received: from xz-x1.redhat.com (ovpn-12-16.pek2.redhat.com [10.72.12.16]) by smtp.corp.redhat.com (Postfix) with ESMTP id 35E145C28C; Wed, 6 Mar 2019 11:55:45 +0000 (UTC) From: Peter Xu To: qemu-devel@nongnu.org Date: Wed, 6 Mar 2019 19:55:28 +0800 Message-Id: <20190306115532.23025-2-peterx@redhat.com> In-Reply-To: <20190306115532.23025-1-peterx@redhat.com> References: <20190306115532.23025-1-peterx@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 06 Mar 2019 11:55:49 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v2 1/5] iothread: replace init_done_cond with a semaphore X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: =?utf-8?q?Marc-Andr=C3=A9_Lureau?= , peterx@redhat.com, Stefan Hajnoczi , Paolo Bonzini Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Only sending an init-done message using lock+cond seems an overkill to me. Replacing it with a simpler semaphore. Meanwhile, init the semaphore unconditionally, then we can destroy it unconditionally too in finalize which seems cleaner. Signed-off-by: Peter Xu --- include/sysemu/iothread.h | 3 +-- iothread.c | 17 ++++------------- 2 files changed, 5 insertions(+), 15 deletions(-) diff --git a/include/sysemu/iothread.h b/include/sysemu/iothread.h index 8a7ac2c528..50411ba54a 100644 --- a/include/sysemu/iothread.h +++ b/include/sysemu/iothread.h @@ -27,8 +27,7 @@ typedef struct { GMainContext *worker_context; GMainLoop *main_loop; GOnce once; - QemuMutex init_done_lock; - QemuCond init_done_cond; /* is thread initialization done? */ + QemuSemaphore init_done_sem; /* is thread init done? */ bool stopping; /* has iothread_stop() been called? */ bool running; /* should iothread_run() continue? */ int thread_id; diff --git a/iothread.c b/iothread.c index e615b7ae52..6e297e9ef1 100644 --- a/iothread.c +++ b/iothread.c @@ -55,10 +55,8 @@ static void *iothread_run(void *opaque) rcu_register_thread(); my_iothread = iothread; - qemu_mutex_lock(&iothread->init_done_lock); iothread->thread_id = qemu_get_thread_id(); - qemu_cond_signal(&iothread->init_done_cond); - qemu_mutex_unlock(&iothread->init_done_lock); + qemu_sem_post(&iothread->init_done_sem); while (iothread->running) { aio_poll(iothread->ctx, true); @@ -115,6 +113,7 @@ static void iothread_instance_init(Object *obj) iothread->poll_max_ns = IOTHREAD_POLL_MAX_NS_DEFAULT; iothread->thread_id = -1; + qemu_sem_init(&iothread->init_done_sem, 0); } static void iothread_instance_finalize(Object *obj) @@ -123,10 +122,6 @@ static void iothread_instance_finalize(Object *obj) iothread_stop(iothread); - if (iothread->thread_id != -1) { - qemu_cond_destroy(&iothread->init_done_cond); - qemu_mutex_destroy(&iothread->init_done_lock); - } /* * Before glib2 2.33.10, there is a glib2 bug that GSource context * pointer may not be cleared even if the context has already been @@ -145,6 +140,7 @@ static void iothread_instance_finalize(Object *obj) g_main_context_unref(iothread->worker_context); iothread->worker_context = NULL; } + qemu_sem_destroy(&iothread->init_done_sem); } static void iothread_complete(UserCreatable *obj, Error **errp) @@ -173,8 +169,6 @@ static void iothread_complete(UserCreatable *obj, Error **errp) return; } - qemu_mutex_init(&iothread->init_done_lock); - qemu_cond_init(&iothread->init_done_cond); iothread->once = (GOnce) G_ONCE_INIT; /* This assumes we are called from a thread with useful CPU affinity for us @@ -188,12 +182,9 @@ static void iothread_complete(UserCreatable *obj, Error **errp) g_free(name); /* Wait for initialization to complete */ - qemu_mutex_lock(&iothread->init_done_lock); while (iothread->thread_id == -1) { - qemu_cond_wait(&iothread->init_done_cond, - &iothread->init_done_lock); + qemu_sem_wait(&iothread->init_done_sem); } - qemu_mutex_unlock(&iothread->init_done_lock); } typedef struct {