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 A09B2C433F5 for ; Tue, 18 Jan 2022 20:39:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349285AbiARUjQ (ORCPT ); Tue, 18 Jan 2022 15:39:16 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58346 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349143AbiARUjM (ORCPT ); Tue, 18 Jan 2022 15:39:12 -0500 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F2E15C061574; Tue, 18 Jan 2022 12:39:11 -0800 (PST) Received: by mail-pg1-x530.google.com with SMTP id p125so297912pga.2; Tue, 18 Jan 2022 12:39:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=rTxSIYtF/qhDMdpcunv+R2Pnv7mrcydD4DvIe4qQgBA=; b=XzNVA7WFscHIr9quBbwN1Zl6DlOEBX9F8WsDR4fZuQmtO7dSeFEckqOuxbRK5Dbr36 /eNURLliqpELZFheqowDPzNq72XN2bbp84c7+2gEmZWBXHzwINhnbQmHL+COLhW/mH7B sEyyYr0KSen0K0Oz8LuUJAMgc5YGn6FdzO6XUxUA0ZHD/46rOBRY6iZqcfjk3s4c3c+G tQ0FJvOpkvJ1cM8BKRmRfnNY0v9QN+Kor7sdjGPNwfcPoNNyO9VuyPm3JdHZi95ha43F kAYsOqWFk/ykFHxFzIQuyr5djbFrIif7ZEGmKHeNwzi3xNaqHdgLcnaN11LGGvahgN+J qjXA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=rTxSIYtF/qhDMdpcunv+R2Pnv7mrcydD4DvIe4qQgBA=; b=4Z/dvufav4Wo9c1JRIIAkMQDTpAoFOh3UJI7ch95hsgeASuC+KgENvTnnMHMP+5PY3 nXS3eJDaWSFAkKZJikinZtbr3KLTC8oRAZdaJIuSSeIEPV3KHV/h6baBjQ5/e7J0AZjs YSB4Ep1Agj8odLY6N8rSCdPu7vVQszFoCV+ok/R/VulrT4P9Yc3uJmgx6ggzje9Dg0BW LKPt1tGswR5J+DMDBPJLe3DlMxPwj9nza66ZBToYcQ0rj8RcZ6lS0fbW4Ipq7ZdVhE3e aTDGUYzPXswFO/HcmuQTPRlfVCZDsi3PXm5FJQRH0ky/Y99hkNFarI/bgHo+aojU3OoH lI5A== X-Gm-Message-State: AOAM5312fx/7fo+T9KBwLSH9zgDl2p5dakka8tUwdf3dWaHiVt6Hvt+8 kC6oRAtTFP66A9DLGzHdoyM= X-Google-Smtp-Source: ABdhPJyeiRPViIFqLAMdX5NCXcv8RFZDx7ydr82FV18KzIXzXluRnjCoqA20Vyi5zu46O1Q7GFBlZw== X-Received: by 2002:a63:191a:: with SMTP id z26mr24598864pgl.593.1642538351256; Tue, 18 Jan 2022 12:39:11 -0800 (PST) Received: from localhost (2603-800c-1a02-1bae-e24f-43ff-fee6-449f.res6.spectrum.com. [2603:800c:1a02:1bae:e24f:43ff:fee6:449f]) by smtp.gmail.com with ESMTPSA id y64sm15227654pgy.12.2022.01.18.12.39.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 Jan 2022 12:39:10 -0800 (PST) Sender: Tejun Heo Date: Tue, 18 Jan 2022 10:39:09 -1000 From: Tejun Heo To: Vipin Sharma Cc: Michal =?iso-8859-1?Q?Koutn=FD?= , pbonzini@redhat.com, seanjc@google.com, lizefan.x@bytedance.com, hannes@cmpxchg.org, dmatlack@google.com, jiangshanlai@gmail.com, kvm@vger.kernel.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] KVM: Move VM's worker kthreads back to the original cgroups before exiting. Message-ID: References: <20211222225350.1912249-1-vipinsh@google.com> <20220105180420.GC6464@blackbody.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On Tue, Jan 18, 2022 at 12:25:48PM -0800, Vipin Sharma wrote: > Automated tools/scripts which delete VM cgroups after the main KVM > process ends were seeing deletion errors because kernel worker threads > were still running inside those cgroups. This is not a very frequent > issue but we noticed it happens every now and then. So, these are normally driven by the !populated events. That's how everyone else is doing it. If you want to tie the kvm workers lifetimes to kvm process, wouldn't it be cleaner to do so from kvm side? ie. let kvm process exit wait for the workers to be cleaned up. Thanks. -- tejun