From nobody Tue Feb 10 14:32:41 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1639565840925754.7934211810312; Wed, 15 Dec 2021 02:57:20 -0800 (PST) Received: from localhost ([::1]:33926 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mxRyJ-0001ay-Vk for importer@patchew.org; Wed, 15 Dec 2021 05:57:20 -0500 Received: from eggs.gnu.org ([209.51.188.92]:38996) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mxRam-0003WR-Gl for qemu-devel@nongnu.org; Wed, 15 Dec 2021 05:33:00 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:37402) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mxRak-0007Mz-M8 for qemu-devel@nongnu.org; Wed, 15 Dec 2021 05:33:00 -0500 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-336-xgo_WzOWOL60z_pGO-nNTw-1; Wed, 15 Dec 2021 05:32:56 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 62D282F24; Wed, 15 Dec 2021 10:32:55 +0000 (UTC) Received: from secure.mitica (unknown [10.39.192.37]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8CFC26E978; Wed, 15 Dec 2021 10:32:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1639564378; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=wEk5ki/Zqr2hQYrP9l+vRms1pIDftUSqOYPfd7Z5i18=; b=H/mqxBicJrrFNrRDH5yfHRLwXKDi974OtlKDuTYMJxO66cuxN/Qm4LX6mxajZlykhRJI1w 1Tz3mwIJXumkuyjDnF+SZJ5kMtNgM/waMUyFkFlLvzGQ9WxEbHVnyUV6N0FvoDX6oRJcPA heWX2mbT2SBA4IinpXREezKF0a1C1tE= X-MC-Unique: xgo_WzOWOL60z_pGO-nNTw-1 From: Juan Quintela To: qemu-devel@nongnu.org Subject: [PULL 15/18] multifd: Shut down the QIO channels to avoid blocking the send threads when they are terminated. Date: Wed, 15 Dec 2021 11:32:15 +0100 Message-Id: <20211215103218.17527-16-quintela@redhat.com> In-Reply-To: <20211215103218.17527-1-quintela@redhat.com> References: <20211215103218.17527-1-quintela@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=quintela@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=quintela@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.719, 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: Li Zhang , =?UTF-8?q?Daniel=20P=20=2E=20Berrang=C3=A9?= , Hailiang Zhang , Juan Quintela , "Dr. David Alan Gilbert" , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) X-ZM-MESSAGEID: 1639565841351100001 From: Li Zhang 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 A= CKs. 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=3D0x55cbb881f418) at ../u= til/qemu-thread-posix.c:627 2 0x000055cbb6b54e40 in multifd_save_cleanup () at ../migration/multifd.c:= 542 3 0x000055cbb6b4de06 in migrate_fd_cleanup (s=3D0x55cbb8024000) at ../migr= ation/migration.c:1808 4 0x000055cbb6b4dfb4 in migrate_fd_cleanup_bh (opaque=3D0x55cbb8024000) at= ../migration/migration.c:1850 5 0x000055cbb7173ac1 in aio_bh_call (bh=3D0x55cbb7eb98e0) at ../util/async= .c:141 6 0x000055cbb7173bcb in aio_bh_poll (ctx=3D0x55cbb7ebba80) at ../util/asyn= c.c:169 7 0x000055cbb715ba4b in aio_dispatch (ctx=3D0x55cbb7ebba80) at ../util/aio= -posix.c:381 8 0x000055cbb7173ffe in aio_ctx_dispatch (source=3D0x55cbb7ebba80, callbac= k=3D0x0, user_data=3D0x0) 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=3D42251070366) at = ../util/main-loop.c:255 12 0x000055cbb7185321 in main_loop_wait (nonblocking=3D0) at ../util/main-l= oop.c:531 13 0x000055cbb6e6ba27 in qemu_main_loop () at ../softmmu/runstate.c:726 14 0x000055cbb6ad6fd7 in main (argc=3D68, argv=3D0x7ffc0c578888, envp=3D0x7= ffc0c578ab0) 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 Reviewed-by: Daniel P. Berrang=C3=A9 Reviewed-by: Dr. David Alan Gilbert Reviewed-by: Juan Quintela Signed-off-by: Juan Quintela --- migration/multifd.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/migration/multifd.c b/migration/multifd.c index 0533da154a..3242f688e5 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -524,6 +524,9 @@ static void multifd_send_terminate_threads(Error *err) qemu_mutex_lock(&p->mutex); p->quit =3D true; qemu_sem_post(&p->sem); + if (p->c) { + qio_channel_shutdown(p->c, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); + } qemu_mutex_unlock(&p->mutex); } } --=20 2.33.1