From nobody Sun Apr 12 07:20:22 2026 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; 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=pass(p=quarantine dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1772007261; cv=none; d=zohomail.com; s=zohoarc; b=DNStT7q+GT8dCv3ZNKDvR9lX8Lav2hpmlBpJZgISlzV1cBuNiJz0B+PHOTdaBMm81O2r4CQwTFAZO/piI0pX/++sUCTFDF+nSlwwZQDLa4toS5DFi3CLRS2+8pYwURpDWsh9ZSHmqMXktlEWgJuri9IgfOY3PwuWZJmKR6gXX00= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1772007261; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=IwK+4U3rA5gsM5s8bZtHt3GmDGzP9xFTquIJLV4EUZ8=; b=S2VA1cmt9rz+Efioy19b/s78dH3Sf7kgL0lb9tR4G5+3Fl7G0gEu397zix7FoWIZsTm+CY29E2MsSS5e6ekpyO6Sjw8ma+OF+zklNodCWCHAB8/uxZQ80RX55DDc5bAsxfzlfxC9FvqVMClSm67fBmUOVtLTCSPSpbCkLAhKon8= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; 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=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1772007261203131.9618622684984; Wed, 25 Feb 2026 00:14:21 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1vvA1y-0000KV-Dj; Wed, 25 Feb 2026 03:14:02 -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 1vvA1w-0000IK-Cu for qemu-devel@nongnu.org; Wed, 25 Feb 2026 03:14:00 -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 1vvA1v-0001n0-1y for qemu-devel@nongnu.org; Wed, 25 Feb 2026 03:14:00 -0500 Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-681-9XxlWmXXM6eZbo-Q3GGWOA-1; Wed, 25 Feb 2026 03:13:54 -0500 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 784211800464; Wed, 25 Feb 2026 08:13:53 +0000 (UTC) Received: from localhost (unknown [10.2.16.120]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 13A331955F43; Wed, 25 Feb 2026 08:13:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1772007238; 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=IwK+4U3rA5gsM5s8bZtHt3GmDGzP9xFTquIJLV4EUZ8=; b=E9dikzebZt8k4K2mdAj/1rvbCA99blah5dc8jAy0fw+tRN6yvOj3WrwY1q91k3AGH4vZ0/ vLAqgQi4ExmYtA0p9pdez7ykB5bxTv9ahT85bnGfljhNYYVYeP+5Jhq63WxrFEAx0TeUGn d5E6kfNHxwYrEQkI6Omoo2jveLFnii8= X-MC-Unique: 9XxlWmXXM6eZbo-Q3GGWOA-1 X-Mimecast-MFC-AGG-ID: 9XxlWmXXM6eZbo-Q3GGWOA_1772007233 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Stefan Hajnoczi , qemu-block@nongnu.org, Kevin Wolf , Fam Zheng , Jens Axboe Subject: [PATCH v2 3/4] aio-posix: enable IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG Date: Wed, 25 Feb 2026 16:13:35 +0800 Message-ID: <20260225081336.1639325-4-stefanha@redhat.com> In-Reply-To: <20260225081336.1639325-1-stefanha@redhat.com> References: <20260225081336.1639325-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 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=170.10.129.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -10 X-Spam_score: -1.1 X-Spam_bar: - X-Spam_report: (-1.1 / 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.358, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.659, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1772007262332158500 Content-Type: text/plain; charset="utf-8" The IORING_SETUP_COOP_TASKRUN flag reduces interprocessor interrupts when an io_uring event occurs on a different CPU. The idea is that the QEMU thread will wait for a CQE anyway, so there is no need to interrupt the CPU that it is on. The IORING_SETUP_TASKRUN_FLAG ensures that QEMU's io_uring CQ ring polling still works with COOP_TASKRUN. The kernel will set a flag in the SQ ring (this is not a typo, the flag is located in the SQ ring even though it pertains to the CQ ring) that can be polled from userspace. Signed-off-by: Stefan Hajnoczi --- util/fdmon-io_uring.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/util/fdmon-io_uring.c b/util/fdmon-io_uring.c index ec056b4818..2e2c0e6785 100644 --- a/util/fdmon-io_uring.c +++ b/util/fdmon-io_uring.c @@ -423,13 +423,16 @@ static int fdmon_io_uring_wait(AioContext *ctx, AioHa= ndlerList *ready_list, =20 static bool fdmon_io_uring_need_wait(AioContext *ctx) { + struct io_uring *ring =3D &ctx->fdmon_io_uring; + /* Have io_uring events completed? */ - if (io_uring_cq_ready(&ctx->fdmon_io_uring)) { + if (io_uring_cq_ready(ring) || + IO_URING_READ_ONCE(*ring->sq.kflags) & IORING_SQ_TASKRUN) { return true; } =20 /* Are there pending sqes to submit? */ - if (io_uring_sq_ready(&ctx->fdmon_io_uring)) { + if (io_uring_sq_ready(ring)) { return true; } =20 @@ -459,7 +462,15 @@ static inline bool is_creating_iothread(void) =20 bool fdmon_io_uring_setup(AioContext *ctx, Error **errp) { - unsigned flags =3D 0; + /* Enable modern flags supported by the host kernel */ + unsigned flags =3D +#ifdef IORING_SETUP_COOP_TASKRUN + IORING_SETUP_COOP_TASKRUN | +#endif +#ifdef IORING_SETUP_TASKRUN_FLAG + IORING_SETUP_TASKRUN_FLAG | +#endif + 0; int ret; =20 /* --=20 2.53.0