From patchwork Wed Jan 31 10:31:11 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Xu X-Patchwork-Id: 13539143 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 51B20C47258 for ; Wed, 31 Jan 2024 10:33:23 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rV7tU-0006eV-R5; Wed, 31 Jan 2024 05:32:36 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rV7tN-0006Y1-JA for qemu-devel@nongnu.org; Wed, 31 Jan 2024 05:32:30 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rV7tL-0005iK-JR for qemu-devel@nongnu.org; Wed, 31 Jan 2024 05:32:28 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1706697146; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=E5BznSsUeQgE8jqC5Fqg/VQQUrmZ60X5UizbN/zWa8g=; b=eTDiCD+fuLzqFcCoLief1vefwzY6ThJsGNMmCprxO5hSeMhuffK93isjhU1+dZFX2K6YSz Q84ngcYzsENczEy6XUuJq2n4REF1zx27gJmcsZtCw2QEcJV4EE88SZnEfhN4cPwv2h+Tfl rFYQOiGvQHshKwSJiK6Iw5eSBEjm7S8= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-636-s4Bcl2GHP66-LulmabqxAg-1; Wed, 31 Jan 2024 05:32:24 -0500 X-MC-Unique: s4Bcl2GHP66-LulmabqxAg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 128D5185A782; Wed, 31 Jan 2024 10:32:24 +0000 (UTC) Received: from x1n.redhat.com (unknown [10.72.116.11]) by smtp.corp.redhat.com (Postfix) with ESMTP id 27EFE1BDB1; Wed, 31 Jan 2024 10:32:19 +0000 (UTC) From: peterx@redhat.com To: qemu-devel@nongnu.org Cc: Bryan Zhang , Prasad Pandit , Fabiano Rosas , peterx@redhat.com, Yuan Liu , Avihai Horon , Hao Xiang Subject: [PATCH 14/14] migration/multifd: Forbid spurious wakeups Date: Wed, 31 Jan 2024 18:31:11 +0800 Message-ID: <20240131103111.306523-15-peterx@redhat.com> In-Reply-To: <20240131103111.306523-1-peterx@redhat.com> References: <20240131103111.306523-1-peterx@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.133.124; envelope-from=peterx@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=-1.292, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Peter Xu Now multifd's logic is designed to have no spurious wakeup. I still remember a talk to Juan and he seems to agree we should drop it now, and if my memory was right it was there because multifd used to hit that when still debugging. Let's drop it and see what can explode; as long as it's not reaching soft-freeze. Signed-off-by: Peter Xu Reviewed-by: Fabiano Rosas --- migration/multifd.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/migration/multifd.c b/migration/multifd.c index 0f22646f95..bd0e3ea1a5 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -766,9 +766,6 @@ static void *multifd_send_thread(void *opaque) p->pending_sync = false; qemu_mutex_unlock(&p->mutex); qemu_sem_post(&p->sem_sync); - } else { - qemu_mutex_unlock(&p->mutex); - /* sometimes there are spurious wakeups */ } }