From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.222.46 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794397521; b=0MLRB6cs+Z++7bhjAzJzmrpQTEpau9UOD3Htk2IIiSfe5g5OF/PQ6Xqs7kFabFMbB42X gPX1yTMuwhmZNLxAlWj9rtqkwbPgXazS56nmTU70tfFVRQQmkRkYnXPb+8VZpLvkkvvoG Y7ck2iyonR4jPuU+9s+pKyOcBD+BVOU6Kgft9QopJTbwHajVH07rMnCYuEnN2oz6Kdwi2 DnGA0tmnuehJxJohxTpgw+csReiWEPR9Vm3nUCJPjXxhhhNKP4fRjGQT/ATUBGiS9LJfj tiS5g4hvXRSTM0QlBHW2J3EIWtVI/SOYNhj8wA55KGwOtu5hHsVwJD442KnEtfFUAKA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794397521; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: Mime-Version:Content-Transfer-Encoding:Content-Type:Date:Message-Id: Cc:Subject:From:To:X-Mailer:References:In-Reply-To; bh=kVFpNKJHonPsoU0rKznaV1aSGj2r5pa7n7k1+LB8yBg=; b=KcWYggm1zSPJ4OaAPrLzbOFshAFzx/yePEot8e+bFa/xkgBB6MdhEcqAvY8AOjKndxsI ujOauzsupjKEzoTojLNytznZUOvWDrGC/xkMIL4v4nr9zxWsGDGT0YzFgPk+EmD7Q7gGP SXDwa7xS26GaevJJrVxpNOYyYyjNp8EowFOhcsCfCezq9PHzw7JV/qkIVpGyTs/OH0Sah ibC5cIj4Iw9erjvvehEYAwN/mW91QG0IXifZkNRD3JzkZIYWSs4Z34X7IquJfFqJaTv8B 0tfIDXguYCEDwiocKR7u8nARLetnN6WmWtfSWqI3NeWg+HQ6yDOw2abbR0K37SCcEtA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=soleen.com; spf=pass smtp.mailfrom=soleen.com; dkim=pass header.d=soleen.com header.i=@soleen.com header.a=rsa-sha256 header.s=google header.b=c9DA1cFS; arc=none smtp.remote-ip=209.85.222.46 Received: from mail-ua1-f46.google.com (mail-ua1-f46.google.com [209.85.222.46]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 29E8E606A336 for ; Wed, 11 Nov 2026 11:45:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 29E8E606A336 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=soleen.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=soleen.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=soleen.com header.i=@soleen.com header.a=rsa-sha256 header.s=google header.b=c9DA1cFS Received: by mail-ua1-f46.google.com with SMTP id a1e0cc1a2514c-99c0c1d07feso1385899241.1 for ; Wed, 11 Nov 2026 03:45:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; t=1794397515; x=1795002315; darn=vger.kernel.org; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-type:content-transfer-encoding:mime-version:from:to:cc :subject:date:message-id:reply-to:content-type; bh=kVFpNKJHonPsoU0rKznaV1aSGj2r5pa7n7k1+LB8yBg=; b=c9DA1cFSmxCvO39uVubU9GovzfKszsFQBrJmlM2Z9CBevLDLmE6mQZuJVOweGh6q92 0i/zFk4uRueqghCvx+g0+EWpI118FoHTAGu+B4lBXBLA4cgYDizfhGfUvUEQ7YGmsFKL m+Xp7kjZh8p19s2Oe8TjPO/gkx1lizaudJ41A2Cz32W6t1h7aNO644Jrm9adsvfwrUWb T9ISwCJMNe01okSmWCNQRK3WtK7JqMxeGtVhdx7lkJUWuP5P0RRYGt/AOr7mBU5aX3r6 pRxCfdWUSag0sw8VpJMWFolX9dxNsern051lY7I2xzQeMMO9clCGP/e1NYzjUyXpksnd 6qvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1794397515; x=1795002315; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-type:content-transfer-encoding:mime-version:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=kVFpNKJHonPsoU0rKznaV1aSGj2r5pa7n7k1+LB8yBg=; b=AHJFCF1w0pLEw1+hxKqsMAMCMZVhqZH++5bd9ag5ABaOox3gc1gdhaLQRuq8p03/Zn rgYHbVxwRLCMqneWpxi3cl6kOXd5PgTJ0C029sr1xS+5HAHZKBux4yqJIlVQxHhaA6O2 hZx9DvTZxjbNS+HErf7HFvF6ioU47cTNtWZtkTmL2dmUetSoplU4IpAJhneVRJD9i8zF FCJ3vPh5xLihcOhuQR4iAIxuNvBoAAZgchWIObY+pYbHGIBXQEqTs8td7A0Ka0l/gXX1 E2BM5ZgI84aOx/KgcixbvDBoELM5Ueu/9B5+Jb2DNdksvutyIRJNjnD5wdrEKdpZrrhH 0qyg== X-Forwarded-Encrypted: i=1; AL+hErHeDZLfg+WnGdC+mT7+6AlqB74UPXNgOhbG1AyjVv/iv/q8VO6IwgDGcj0TRGmAf4jsHKSjmSGM2Z4=@vger.kernel.org X-Gm-Message-State: APuU4Z9NPtf/UVZP9v2XzR+MxY512d4lMZGy65AXeG2sP4fGghSAYLaP Kn+GdjVuVTmpgEDRPCl7Y3rFEeGffqg0Y12UFB0X1LlQ8wO6SMjezGqakRIMuQnBElM= X-Gm-Gg: AYBFou0nj5eJ7vHAlmMQBVZj3nyk4O0Zg0G05ZrwT1eBtuP6zHa6D3iN5YB7T+zGfAd wmw+2hnLFa7w3P846u6wprYHko9tZNaP6K15VDWv+4HuF52SiNEaSBjRoJVoOKQpIDFrmRnVd28 m7ojZyeIuosGVdmhXEXeVQ/SFxkjFo3gQ7vQStQwx7ctMzOadtAs4mnqM1o4QvtG7SJ/MliLt/M r+mGk4z14INccA6M/yUlx/2uPxJ77RqFFcRSWOC9mjadVtoUDOdpzlTjj6vZmmb0XbKMX56z/k/ r6KaI6Db/wY1ffr1heNaVacdmBHbxc87Pw54sikSE8OvDuwsjtv/69RBI3pRa/2KRGvXPGLsKFu 6yCrmMvluXJvKkjdBMfmvyoj7UoaE5rS7Vpa7E25XFnZcJw1NRJsM36SmgT7y7JmuH6Vb965vhH JGrbqxS/GUxFgKU9TPuSeNBPrF37ZD9PxDNFr4AwlbnA5DuIqViv+TbgmON9tMgxblwn3C05OC+ n8C5XWIUrbwsaMSfLSs3dN/7S/L+Ce8drdSUmRcGO1PyH/LEMYmB9YcQA/anhVKrM/8PBGcYe39 h359IgSBC7aMnqhEaihAASFQXKQzvY9k2k8Gkb0ZtnEUqf1J76Y5ru8poq94NecZZ1FMFzTPsNN itZ2f+kBf0uLx37vX2XUiO166DRpA0lQ= X-Received: by 2002:a05:6102:5241:b0:7cc:306:d3ab with SMTP id ada2fe7eead31-7d4efab730fmr666726137.5.1794397515001; Wed, 11 Nov 2026 03:45:15 -0800 (PST) Received: from localhost (64.167.245.35.bc.googleusercontent.com. [35.245.167.64]) by smtp.gmail.com with ESMTPSA id ada2fe7eead31-7d3023543casm3548860137.5.2026.11.11.03.45.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 11 Nov 2026 03:45:14 -0800 (PST) X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 11 Nov 2026 06:45:13 -0500 Message-Id: Cc: , , , , , , , , , , , , Subject: Re: [PATCH v5 0/6] liveupdate: Add LIVEUPDATE_SESSION_FREEZE ioctl From: "Pasha Tatashin" To: "Mike Rapoport" , "Pasha Tatashin" X-Mailer: aerc 0.22.0-39-g5d7784875be2 References: <20261105050053.3063001-1-pasha.tatashin@soleen.com> <179439592040.425130.10808690337075841196.b4-review@b4> In-Reply-To: <179439592040.425130.10808690337075841196.b4-review@b4> On Wed Nov 11, 2026 at 6:18 AM EST, Mike Rapoport wrote: > Hi, > >> Currently, LUO freezes outgoing sessions only inside the >> reboot(LINUX_REBOOT_CMD_KEXEC) syscall path, serially under global write >> locks, and binds every outgoing session's lifetime strictly to an open >> session FD until reboot. >>=20 >> On hosts running many workloads (such as VMs or stateful daemons), >> workloads do not all pause simultaneously inside reboot(): they quiesce >> one by one ahead of the host kexec. Userspace needs an explicit >> per-session freeze point to snapshot final file state (.freeze()) as >> each workload pauses -- concurrently across sessions under per-session >> locks -- along with a way to commit a frozen session into KHO so it >> survives closing the session FD. >>=20 >> This series introduces LIVEUPDATE_SESSION_FREEZE on session FDs: >>=20 >> 1. Freeze (flags =3D=3D 0): >> Freezes all preserved files in the session under the per-session >> mutex while keeping session lifetime tied to the session FD. The >> session stays frozen as long as the FD remains open; closing the >> session FD before reboot (for example, to abort the session or on >> process exit/crash) runs .unfreeze() and .unpreserve() and reclaims >> all resources. At kexec time, already-frozen sessions skip the late >> auto-freeze step and are published into the outgoing KHO subtree. > > Let me bikeshed for a moment :) > I'm not fond of "published" terminology. We just moved serialization > from one place to another, why not keep the naming? sgtm, I serialization it is. --=20 Pasha