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 799AACD4F2C for ; Thu, 13 Nov 2025 01:18:54 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vJLyB-0003iS-4s; Wed, 12 Nov 2025 20:17:51 -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 1vJLxC-0002eL-Cn for qemu-devel@nongnu.org; Wed, 12 Nov 2025 20:16:55 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1vJLx9-0005ot-U2 for qemu-devel@nongnu.org; Wed, 12 Nov 2025 20:16:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1762996607; 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=5HM5oaVsmC5AOl56uV2/EDSNC6XKx/WmefwcpkerDYs=; b=VziTXrVs0Hsb7awpST5gp9aJl6LkS61i5J053ZVIKyMJCcaq67d0AjbWMQb44af5RhZXjL 8LSeMRTj3850u591UvhQJrHnQnPoklUAbbyJtkPZiVuYKdVoboPUIXItK2CwESTUxhr5I5 QP3Wz0fbVpRRVZ9RHAH+c2ygPvRJang= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-321-r_uFR_pbNsCvDBaWRmQOhA-1; Wed, 12 Nov 2025 20:16:44 -0500 X-MC-Unique: r_uFR_pbNsCvDBaWRmQOhA-1 X-Mimecast-MFC-AGG-ID: r_uFR_pbNsCvDBaWRmQOhA_1762996603 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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 mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id E9A071956089; Thu, 13 Nov 2025 01:16:42 +0000 (UTC) Received: from green.redhat.com (unknown [10.2.16.87]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id D951A180094B; Thu, 13 Nov 2025 01:16:41 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Cc: qemu-block@nongnu.org, kwolf@redhat.com, berrange@redhat.com Subject: [PATCH v3 06/13] qio: Minor optimization when callback function is unchanged Date: Wed, 12 Nov 2025 19:11:31 -0600 Message-ID: <20251113011625.878876-21-eblake@redhat.com> In-Reply-To: <20251113011625.878876-15-eblake@redhat.com> References: <20251113011625.878876-15-eblake@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.129.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org In qemu-nbd and other NBD server setups where parallel clients are supported, it is common that the caller will re-register the same callback function as long as it has not reached its limit on simultaneous clients. In that case, there is no need to tear down and reinstall GSource watches in the GMainContext. In practice, all existing callers currently pass NULL for notify, and no caller ever changes context across calls (for async uses, either the caller consistently uses qio_net_listener_set_client_func_full with the same context, or the caller consistently uses only qio_net_listener_set_client_func which always uses the global context); but the time spent checking these two fields in addition to the more important func and data is still less than the savings of not churning through extra GSource manipulations when the result will be unchanged. Signed-off-by: Eric Blake Reviewed-by: Daniel P. Berrangé --- v2: move later in series, also ensure notify and context are the same v3: rebase to mutex, R-b kept --- io/net-listener.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/io/net-listener.c b/io/net-listener.c index f70acdfc5ce..93100a2d253 100644 --- a/io/net-listener.c +++ b/io/net-listener.c @@ -169,6 +169,11 @@ void qio_net_listener_set_client_func_full(QIONetListener *listener, size_t i; QEMU_LOCK_GUARD(&listener->lock); + if (listener->io_func == func && listener->io_data == data && + listener->io_notify == notify && listener->context == context) { + return; + } + trace_qio_net_listener_unwatch(listener, listener->io_func, listener->context, "set_client_func"); -- 2.51.1