From mboxrd@z Thu Jan 1 00:00:00 1970 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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 90641C433F5 for ; Mon, 6 Dec 2021 19:53:17 +0000 (UTC) Received: from localhost ([::1]:49898 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1muK32-0006YT-7g for qemu-devel@archiver.kernel.org; Mon, 06 Dec 2021 14:53:16 -0500 Received: from eggs.gnu.org ([209.51.188.92]:54842) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1muK0I-0003OJ-Hu for qemu-devel@nongnu.org; Mon, 06 Dec 2021 14:50:31 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:35215) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1muK0F-0000wg-3X for qemu-devel@nongnu.org; Mon, 06 Dec 2021 14:50:25 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1638820221; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Rg27ycbUIPZJ6JuX/QH9pDZOL8kxJGk+TxAWt5hbA8w=; b=Lzihv0haCgf9BnJmEqzjsRSGrlLb0E7NQwnI36X8vXrN2kY8bapqvwWV6iE904W4tiO/Iq aHAyzYMV29eBNTrRbBzWlaDRWJveX0VY6LY9E3ekJP4T6Dzh2sXn1hk7XbPXScSKOvIffa qSFQSJhTbvxVxhTGEnUEptQq/8r4Adk= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-362-7RNv63r_Oiy_l_-KspRksQ-1; Mon, 06 Dec 2021 14:50:20 -0500 X-MC-Unique: 7RNv63r_Oiy_l_-KspRksQ-1 Received: by mail-wm1-f71.google.com with SMTP id i131-20020a1c3b89000000b00337f92384e0so71560wma.5 for ; Mon, 06 Dec 2021 11:50:20 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=Rg27ycbUIPZJ6JuX/QH9pDZOL8kxJGk+TxAWt5hbA8w=; b=wYR+RQTKFeU+fpfP+bPFWXYKALSAL+H25A1Aa1eLea0DR1gtdT4t0gMr4OYdMulnX8 Af7oNZD15VnkvOEsZApDc89V3t75MQxZYAYi99/7+Vb5yAY2w6QNXMn7AWzzOGYUyo1X gcdxadiuYSJdCZ8tqtKsDqq0kexzpXabc7kcluPccafy5TtfpjBb0cEX8zFPQwpomua3 2lg43NCqXqHNz9oeYETbt7hwqhYiGAVUOEfKwX7uAJCLTC+Z2YM9SmnBkzcsEnKPAPEC ebAorEy2g5mXZ320cGqwF7soYTwYMHFFbRZzXW341PO2YQqh52m4WLXcEFB3O5hZX0wY bJAg== X-Gm-Message-State: AOAM533eY6l8q3PrmFjSzpPT4wAYSI8AkHUbs0m5LcqRy/jrCydT1WD2 mqM87YPJmWWGO+E8cv+dVK7JE9BC4/IJgCII5vvQJzoh0lx9kKw2H2k3vY3QmzDna+9ht0lbX4q nxHqnJtZUZ7t2eZY= X-Received: by 2002:a5d:4582:: with SMTP id p2mr46441678wrq.364.1638820219079; Mon, 06 Dec 2021 11:50:19 -0800 (PST) X-Google-Smtp-Source: ABdhPJyh8GTD7+qNEGN1uYjNDJwRuXr0BnvQq/gImQFWMm09h3EIAaluuyWAy7tVO7hmS2qA31WFrw== X-Received: by 2002:a5d:4582:: with SMTP id p2mr46441655wrq.364.1638820218869; Mon, 06 Dec 2021 11:50:18 -0800 (PST) Received: from work-vm (cpc109025-salf6-2-0-cust480.10-2.cable.virginm.net. [82.30.61.225]) by smtp.gmail.com with ESMTPSA id x4sm326710wmi.3.2021.12.06.11.50.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 Dec 2021 11:50:18 -0800 (PST) Date: Mon, 6 Dec 2021 19:50:15 +0000 From: "Dr. David Alan Gilbert" To: Li Zhang Subject: Re: [PATCH v2 1/1] multifd: Shut down the QIO channels to avoid blocking the send threads when they are terminated. Message-ID: References: <20211203115533.31534-1-lizhang@suse.de> <20211203115533.31534-2-lizhang@suse.de> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.1.3 (2021-09-10) Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=dgilbert@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Received-SPF: pass client-ip=170.10.133.124; envelope-from=dgilbert@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -33 X-Spam_score: -3.4 X-Spam_bar: --- X-Spam_report: (-3.4 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.619, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-devel@nongnu.org, berrange@redhat.com, cfontana@suse.de, quintela@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Li Zhang (lizhang@suse.de) wrote: > > Thanks for Daniel's review. > > Hi David and Juan, > > Any comments for this patch? > Yeh I think that's OK, so Reviewed-by: Dr. David Alan Gilbert I'd have a slight preference for it being before the post I think. Dave > > Thanks > > Li > > On 12/3/21 12:55 PM, Li Zhang wrote: > > When doing live migration with multifd channels 8, 16 or larger number, > > the guest hangs in the presence of the network errors such as missing TCP ACKs. > > > > At sender's side: > > The main thread is blocked on qemu_thread_join, migration_fd_cleanup > > is called because one thread fails on qio_channel_write_all when > > the network problem happens and other send threads are blocked on sendmsg. > > They could not be terminated. So the main thread is blocked on qemu_thread_join > > to wait for the threads terminated. > > > > (gdb) bt > > 0 0x00007f30c8dcffc0 in __pthread_clockjoin_ex () at /lib64/libpthread.so.0 > > 1 0x000055cbb716084b in qemu_thread_join (thread=0x55cbb881f418) at ../util/qemu-thread-posix.c:627 > > 2 0x000055cbb6b54e40 in multifd_save_cleanup () at ../migration/multifd.c:542 > > 3 0x000055cbb6b4de06 in migrate_fd_cleanup (s=0x55cbb8024000) at ../migration/migration.c:1808 > > 4 0x000055cbb6b4dfb4 in migrate_fd_cleanup_bh (opaque=0x55cbb8024000) at ../migration/migration.c:1850 > > 5 0x000055cbb7173ac1 in aio_bh_call (bh=0x55cbb7eb98e0) at ../util/async.c:141 > > 6 0x000055cbb7173bcb in aio_bh_poll (ctx=0x55cbb7ebba80) at ../util/async.c:169 > > 7 0x000055cbb715ba4b in aio_dispatch (ctx=0x55cbb7ebba80) at ../util/aio-posix.c:381 > > 8 0x000055cbb7173ffe in aio_ctx_dispatch (source=0x55cbb7ebba80, callback=0x0, user_data=0x0) at ../util/async.c:311 > > 9 0x00007f30c9c8cdf4 in g_main_context_dispatch () at /usr/lib64/libglib-2.0.so.0 > > 10 0x000055cbb71851a2 in glib_pollfds_poll () at ../util/main-loop.c:232 > > 11 0x000055cbb718521c in os_host_main_loop_wait (timeout=42251070366) at ../util/main-loop.c:255 > > 12 0x000055cbb7185321 in main_loop_wait (nonblocking=0) at ../util/main-loop.c:531 > > 13 0x000055cbb6e6ba27 in qemu_main_loop () at ../softmmu/runstate.c:726 > > 14 0x000055cbb6ad6fd7 in main (argc=68, argv=0x7ffc0c578888, envp=0x7ffc0c578ab0) at ../softmmu/main.c:50 > > > > To make sure that the send threads could be terminated, IO channels should be > > shut down to avoid waiting IO. > > > > Signed-off-by: Li Zhang > > --- > > migration/multifd.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/migration/multifd.c b/migration/multifd.c > > index 7c9deb1921..33f8287969 100644 > > --- a/migration/multifd.c > > +++ b/migration/multifd.c > > @@ -523,6 +523,9 @@ static void multifd_send_terminate_threads(Error *err) > > qemu_mutex_lock(&p->mutex); > > p->quit = true; > > qemu_sem_post(&p->sem); > > + if (p->c) { > > + qio_channel_shutdown(p->c, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); > > + } > > qemu_mutex_unlock(&p->mutex); > > } > > } > > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK