From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f45.google.com (mail-ed1-f45.google.com [209.85.208.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2E6BC194A42; Wed, 10 Jul 2024 17:53:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720633999; cv=none; b=A0TjvDZlZfBhoPsW4qnKNKuHMhX5txTA6y8oefyzdF70ezWrhgY9Ot9EBHcyJu0wV6mgNJPGcxBHd+j+v6+TTXUX+OTXabvzorthU549TnjVJ2kj3U9orGPUz1UPWJg6dBIk0dOhJRumJspIr/SHRCVFqIvHsPI+r8HRK8ryQO8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720633999; c=relaxed/simple; bh=Xq2De5RSGg1NmnAIQvQ91dbnaUJe8oskkK/ToRdTpeE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ngbHPJ0pKooYiv+5NnbkSrTXHESglDqvM7HqxNoF7GJpY2OVaQwEfy8MCC7XhRMVV6DjwCoA8tNGakpq+N9+qlD03Zd8r9oO41ckMcx0MKIARMOVJviKXePk0I2y0ROJ2HCq+nrf93QsXQnxZrhLy4VOEJKyEWGTjO7Pi2sRit0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=biyGnZ9l; arc=none smtp.client-ip=209.85.208.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="biyGnZ9l" Received: by mail-ed1-f45.google.com with SMTP id 4fb4d7f45d1cf-585e774fd3dso27510a12.0; Wed, 10 Jul 2024 10:53:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1720633996; x=1721238796; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=2AkJn534ghJu7YwSCibF8mdGkKnNNVFldDG6paceURc=; b=biyGnZ9l3TEXpyQukMWr5jr/C3U69c00pf+XUNiV2W4xCILbfVRXACyvvXQhvnUIh/ xT1uizaGB7A1cEolCwXDogvt6I3rkHrXzo+PwIuMVLLCjOg63qWt6ho/Ieq4NqjOGw4/ +mkFjvZINoXsTJ9Q6qLs+4SyA9AdgJzLXHmaU3iq3eG2HhmBx4m4Xd/G2kwdWjxaTH6k XrITwr3LL1HvVbB/c9uHtRMbKkkdlvYCcQafK6sSJbrbE7qDPPWalpIQCtR3zLpQE2S8 5EfnI8UHcz/j3pMI+kUntGLvHKerOSieSRJSR5MUTZIv6pgtxqXXRlZL13A9onaiPMrn UAcg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1720633996; x=1721238796; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=2AkJn534ghJu7YwSCibF8mdGkKnNNVFldDG6paceURc=; b=AWWqLKbHQvD1WOLLzLPo3FV9w1EzbE6TOVs2PhrE+Poc8DIQHEUMj75DAQ7H60lzRU xN86ICuOGPOZ3JdON0FRGGf59WnaI7Xy8enFDAtRxoAin1qFyXGzX8tLdKAP0VXgWqF4 GveMMePAni2NywxUNxgg68FGmbxpeTW32OoqB50xi1U5JoSv3hM8OAY10OWxzc9IG6uI EQSE2bqaUFMZDM3KEznH25kjEdXHN9AtwughNTLfgEgR7U+UGN0gAikEEgoW8vd3fI4k PvB+vhiTqOV33wi+iGRBdu2/B+3l3fDdJbr8Fjkmm0m6yGStb94kpqxOuzkkjQ9y6CL6 5jpQ== X-Forwarded-Encrypted: i=1; AJvYcCX8pRL9Kp7fDaV681KyMXqqp/WlT0ONhy5omH7FbofhNrrJ1QAA9ECTNfFbHrjnmXceqbnxd2OYPQJ7aKkJ/7oJjNsZQVR+WlA5C+6U+Rt6acm3j+Da9D9mhy8JjARF78Q3dB89ujg= X-Gm-Message-State: AOJu0Yziaqhrf4AOegv39AHIkblZnZRaBHc+eFzYGLCSjBbJIV0kyBuE bf4pF7t+9AeiauhjDNbKT+jHzUaNXg+fuUSQNPI59CQN9R3xkh1i X-Google-Smtp-Source: AGHT+IHT7B3oKYmPm0YZHF0+OmcYnvb8qL8CRz0AUI+iyXmC12ZJRRGvbadITN1ppbA4s4ABVVLhng== X-Received: by 2002:a05:6402:3512:b0:57d:692:92d9 with SMTP id 4fb4d7f45d1cf-594ba98e73amr4587113a12.4.1720633977357; Wed, 10 Jul 2024 10:52:57 -0700 (PDT) Received: from [192.168.42.235] ([163.114.131.193]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-594bd459ddasm2452569a12.64.2024.07.10.10.52.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 10 Jul 2024 10:52:56 -0700 (PDT) Message-ID: <933e7957-7a73-4c9a-87a7-c85b702a3a32@gmail.com> Date: Wed, 10 Jul 2024 18:53:03 +0100 Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] kernel: rerun task_work while freezing in get_signal() To: Tejun Heo Cc: Oleg Nesterov , io-uring@vger.kernel.org, Jens Axboe , Andrew Morton , Christian Brauner , Tycho Andersen , Thomas Gleixner , linux-kernel@vger.kernel.org, Julian Orth , Peter Zijlstra References: <1d935e9d87fd8672ef3e8a9a0db340d355ea08b4.1720368770.git.asml.silence@gmail.com> <20240708104221.GA18761@redhat.com> <62c11b59-c909-4c60-8370-77729544ec0a@gmail.com> <20240709103617.GB28495@redhat.com> <658da3fe-fa02-423b-aff0-52f54e1332ee@gmail.com> <20240709190743.GB3892@redhat.com> <20240709193828.GC3892@redhat.com> Content-Language: en-US From: Pavel Begunkov In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/10/24 01:54, Tejun Heo wrote: > Hello, > > On Tue, Jul 09, 2024 at 08:55:43PM +0100, Pavel Begunkov wrote: > ... >>>> CRIU, I assume. I'll try it ... >>> >>> Than I think we can forget about task_works and this patch. CRIU dumps >>> the tasks in TASK_TRACED state. >> >> And would be hard to test, io_uring (the main source of task_work) >> is not supported >> >> (00.466022) Error (criu/proc_parse.c:477): Unknown shit 600 (anon_inode:[io_uring]) >> ... >> (00.467642) Unfreezing tasks into 1 >> (00.467656) Unseizing 15488 into 1 >> (00.468149) Error (criu/cr-dump.c:2111): Dumping FAILED. > > Yeah, the question is: If CRIU is to use cgroup freezer to freeze the tasks > and then go around tracing each to make dump, would the freezer be enough in > avoiding interim state changes? Using CRIU implementation is a bit arbitrary > but I think checkpoint-restart is a useful bar to measure what should stay > stable while a cgroup is frozen. Sounds like in the long run we might want to ignore task_work while it's frozen, but hard to say for all task_work users. -- Pavel Begunkov