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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 68D6DC433FE for ; Tue, 8 Mar 2022 06:20:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344470AbiCHGVw (ORCPT ); Tue, 8 Mar 2022 01:21:52 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1344505AbiCHGVr (ORCPT ); Tue, 8 Mar 2022 01:21:47 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFCC43CA5A for ; Mon, 7 Mar 2022 22:20:48 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8CB4BB817B3 for ; Tue, 8 Mar 2022 06:20:47 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPS id 527B4C340FA for ; Tue, 8 Mar 2022 06:20:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1646720446; bh=39cY+lv1ZzNQSbo3dE5ra/AZNAElz6LPcKd5HatsAP0=; h=From:To:Subject:Date:In-Reply-To:References:From; b=lqaL1pp+MbEenJ4lYNhkHFujMaOEDxgxrIBlxEGW8Bok6fBb0KmIwAs6uRrZMhJu2 v5fr4SGMlHdUlahfps49fndmz1vG0EXeZd9jXkOAuR03/HQ2vQTyoxJLcMay1w+ES6 g8mb0bO9pqwZ90izwO1/Ie1tH4AGyli6WUgufHwW0rwlLKdZjjx9aZOKHF7WvvgdEC SfaIs3X0xJDiPK9PQCd45TZmoOsso4munOTNHLITtTHKlWn5Kr920DTQswbkVvFfo5 pS5Fp1W/ORB3AUnjm4NTUTZcPOVWzMEJumUdN9HOXy2VRhjWbmujdkcOeFOxMNtuHJ iFW8PvGZW0u1A== Received: by aws-us-west-2-korg-bugzilla-1.web.codeaurora.org (Postfix, from userid 48) id 2EFD3C05F98; Tue, 8 Mar 2022 06:20:46 +0000 (UTC) From: bugzilla-daemon@kernel.org To: kvm@vger.kernel.org Subject: [Bug 199727] CPU freezes in KVM guests during high IO load on host Date: Tue, 08 Mar 2022 06:20:44 +0000 X-Bugzilla-Reason: None X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: AssignedTo virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Product: Virtualization X-Bugzilla-Component: kvm X-Bugzilla-Version: unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: high X-Bugzilla-Who: stefanha@gmail.com X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: virtualization_kvm@kernel-bugs.osdl.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugzilla.kernel.org/ Auto-Submitted: auto-generated MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org https://bugzilla.kernel.org/show_bug.cgi?id=3D199727 --- Comment #14 from Stefan Hajnoczi (stefanha@gmail.com) --- (In reply to Roland Kletzing from comment #13) > hello, thanks - aio=3Dio_uring is no better, the only real way to get to a > stable system is virtio-scsi-single/iothreads=3D1/aio=3Dthreads >=20 > the question is why aio=3Dnative and io_uring has issues and threads has = not... Are you using cache=3Dnone with io_uring and the io_uring_enter(2) syscall = is blocking for a long period of time? aio=3Dthreads avoids softlockups because the preadv(2)/pwritev(2)/fdatasync= (2) syscalls run in worker threads that don't take the QEMU global mutex. There= fore vcpu threads can execute even when I/O is stuck in the kernel due to a lock. io_uring should avoid that problem too because it is supposed to submit I/O truly asynchronously. --=20 You may reply to this email to add a comment. You are receiving this mail because: You are watching the assignee of the bug.=