From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44345) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fSPwc-0004p9-1X for qemu-devel@nongnu.org; Mon, 11 Jun 2018 12:45:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fSPwX-0002Ry-1F for qemu-devel@nongnu.org; Mon, 11 Jun 2018 12:45:26 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:41084 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fSPwW-0002Rd-PW for qemu-devel@nongnu.org; Mon, 11 Jun 2018 12:45:20 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E5776BB428 for ; Mon, 11 Jun 2018 16:45:19 +0000 (UTC) Date: Mon, 11 Jun 2018 17:45:16 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20180611164516.GI2661@work-vm> References: <20180523111817.1463-1-quintela@redhat.com> <20180523111817.1463-12-quintela@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180523111817.1463-12-quintela@redhat.com> Subject: Re: [Qemu-devel] [PATCH v13 11/12] migration: Remove not needed semaphore and quit List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Juan Quintela Cc: qemu-devel@nongnu.org, lvivier@redhat.com, peterx@redhat.com * Juan Quintela (quintela@redhat.com) wrote: > We know quit closing the QIO. This patch does two different things; one of which I think I understand. The 'quit' has been removed - I think that makes sense because the multifd threads terminate when either they come to the end of a stream or hit an error; there's no case of asking them to quit explicitly. The 'sem' was basically for kicking the recv-thread to quit; which again isn't needed. Now, what about the object_unref on p->c ? If I've got this right multifd_recv_terminate_threads is only called in the error case; but doesn't multifd_load_cleanup also get called in that case - it does the unref and p->c = NULL as well. Dave > Signed-off-by: Juan Quintela > --- > migration/ram.c | 11 ++--------- > 1 file changed, 2 insertions(+), 9 deletions(-) > > diff --git a/migration/ram.c b/migration/ram.c > index a707d3ae80..62eea9e02f 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -587,14 +587,10 @@ typedef struct { > QemuThread thread; > /* communication channel */ > QIOChannel *c; > - /* sem where to wait for more work */ > - QemuSemaphore sem; > /* this mutex protects the following parameters */ > QemuMutex mutex; > /* is this channel thread running */ > bool running; > - /* should this thread finish */ > - bool quit; > /* array of pages to receive */ > MultiFDPages_t *pages; > /* packet allocated len */ > @@ -1115,8 +1111,8 @@ static void multifd_recv_terminate_threads(Error *err) > MultiFDRecvParams *p = &multifd_recv_state->params[i]; > > qemu_mutex_lock(&p->mutex); > - p->quit = true; > - qemu_sem_post(&p->sem); > + object_unref(OBJECT(p->c)); > + p->c = NULL; > qemu_mutex_unlock(&p->mutex); > } > } > @@ -1139,7 +1135,6 @@ int multifd_load_cleanup(Error **errp) > object_unref(OBJECT(p->c)); > p->c = NULL; > qemu_mutex_destroy(&p->mutex); > - qemu_sem_destroy(&p->sem); > qemu_sem_destroy(&p->sem_sync); > g_free(p->name); > p->name = NULL; > @@ -1262,9 +1257,7 @@ int multifd_load_setup(void) > MultiFDRecvParams *p = &multifd_recv_state->params[i]; > > qemu_mutex_init(&p->mutex); > - qemu_sem_init(&p->sem, 0); > qemu_sem_init(&p->sem_sync, 0); > - p->quit = false; > p->id = i; > p->pages = multifd_pages_init(page_count); > p->packet_len = sizeof(MultiFDPacket_t) > -- > 2.17.0 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK