From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 69B91606A88E for ; Wed, 11 Nov 2026 11:45:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=soleen.com header.i=@soleen.com header.a=rsa-sha256 header.s=google header.b=KWOnhTEn Received: by kanga.kvack.org (Postfix) id 88EAE6B05B0; Wed, 11 Nov 2026 06:45:18 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 866B96B05B3; Wed, 11 Nov 2026 06:45:18 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 77CC36B05B4; Wed, 11 Nov 2026 06:45:18 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 4F9456B05B0 for ; Wed, 11 Nov 2026 06:45:18 -0500 (EST) Received: from smtpin24.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id DF4891C26E2 for ; Wed, 11 Nov 2026 11:45:17 +0000 (UTC) X-FDA: 85422657474.24.F8F8FB5 Received: from mail-ua1-f54.google.com (mail-ua1-f54.google.com [209.85.222.54]) by imf20.hostedemail.com (Postfix) with ESMTP id 031921C000D for ; Wed, 11 Nov 2026 11:45:15 +0000 (UTC) Authentication-Results: imf20.hostedemail.com; dkim=pass header.d=soleen.com header.s=google header.b=KWOnhTEn; spf=pass (imf20.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.222.54 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com; dmarc=pass (policy=reject) header.from=soleen.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1794397516; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=kVFpNKJHonPsoU0rKznaV1aSGj2r5pa7n7k1+LB8yBg=; b=4F4kZNpcGjI18QWFeRZJsgFQ1iXK5/3hR7PmGxuafWUbNoK4P6J1qns+Cqk1dqqbdN2hDG f4Sfa5jnnrepezxD+o3jRhkQBvQ9U2wDlqzJxRzrB0BNWdJ3j2Enbj5VDnbYqXwOUtO2aL ZBv3hNbyDO8UoSNDZJPY8Rn4br57Hts= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1794397516; b=Ws/NtsGXEZR+1mHvM+etXI6l2IU4dNXjBdnyKYm01hSJrN7Xs6UsHzezMrzI7E1N0vmWb7 cqVQEJ5YvUrdhC0q5FEO3BYEcYm8NTgP2dxFcQTL/D7Vw2T175En/06RrirR6yOSqb655B NDW2ctgm+7ldX4DfaAiXT8L7Or2pXVM= ARC-Authentication-Results: i=1; imf20.hostedemail.com; dkim=pass header.d=soleen.com header.s=google header.b=KWOnhTEn; spf=pass (imf20.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.222.54 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com; dmarc=pass (policy=reject) header.from=soleen.com Received: by mail-ua1-f54.google.com with SMTP id a1e0cc1a2514c-99c0c1d07feso1385900241.1 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=kvack.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=KWOnhTEnvgP4QOIxn/FNRDIubnde20ZOp0JPrfmv7U4mzVJwD2vIhoNAhs8iThKDxx ZvKa+mv8MpHXjXc0e52vkp1qEoiGzHctAd6AzErGMm6DhlrnNyIURUFHuD9Er62k/8cZ G+UfewRzIouo4omoB4ukH3qP6yPR2XLF/a2EkeGGnHUQ6vT31D7+OCcSjbN2Zj6FYjq3 kjg7dBxpSauv7nkwTEN716Bxaa3Twte+FeaCPeOpJ8X7QPRRBioWQTVFkHKgLYyIGtPv z2dmAYQE1X3zvJvY7VTWe+sQrIMakKZnJrC+TYyI2QZrUy1873E4RQZask0C2MKaL0la 7l4g== 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=hYdnrJ69qvtQZ4N/pcR5JzjnwoQ2W3tnlJ8KiE8bvExst0w8n/f23z3vyKW3auytDy 6KhTz4Ilz8Ge8Wy0u9CTTPn9aTA5y4C0wcYrw36kIqPI0dBEAtHZrTlolQv0VAacBtZF RKCQBwH5jWlXSnFdGaL2ETIQcMMCeovvy7k/sjhOWummTXI9LnkPVKFumIXwYnhDVDO3 fzgsZPox9fXJH3Zbi//L7LhDdRgKIJXpM6OLyAx51s8dLHiBswjt4PN4CkT8hlK9M9dL bGpadLb5uPbE0GucjANkBdmfTEaF3mPXArZLiLEg/6rbblUq2iuIbU2cEJh2+ZJCSTGj wo0g== X-Forwarded-Encrypted: i=1; AL+hErE/Ev8uKJSah/449VMIBhkUeCuPqG56kqGp6PM8fp9Q7dx4q5qbaBXj9wQnZLSEgcysGiCJH4WWRg==@kvack.org X-Gm-Message-State: APuU4Z9KUrixpih2pATbfo6zsiEtMW0g0JYTDcn82BRitcRN7t1FCHPF L4kbLJXg/jA0bIMyMq8WhNaZm807z/aNKP/7OYhwtEPKGHTBFlE5OI6vjIyG2iB5hdA= X-Gm-Gg: AYBFou2J3J4ZxFoHLbwrTwni43vT41vx1VXFXDxuyrI8wRHQnuu/E+E1sFQAa4gjabs bJ7nO26I71oUHWZ4wiEZiI2dyHyJDcktnroqtCM8QUfTgOHpthy/jRnUcAlqTG0sYvFITBhhlsL TAQAHYBQfJcoJuZ74JkmClwVmKyKHh8rxxYiek1znhQ9kK6uaINBjMB3QJvWYcUGqc8hm5vLXOs eBHz6i9wTfTswVaBxsodb8c1aeFAZnogIJYmShiTRyM+9EPBQR428mCPCFBV+NMyJILqTtXI+x/ Uj0bua8jQ7ImEN5YL8lcmCpUzSRVvFNIhV1/PM8Unav82oGh1EZGzsWT9Y5yDUjCPfZPIIk5tiN I+Blul1hTXv7xA/YCCnw7OPqzVqmYkJCstn9Zd2W042II27BcVUblC7i8DSRcfWtGfcr7xjEZRT CO/QUMVTVPxksIr+nGzcxSP5itd4tpOQqfERY0pvkffM15EU9uwCW9jxVD7pHnu1/KMkAjaf6pz fhoZBqcR9oIV3qEuSL+7Gbup1byGWMWs69EyhCtOyRkfSW3Y22gytv1Ak5W8490+pvsY+UbZekh U0qZ7qnAvX6akzqJG1MmfcOlc46TBwqVK1SZnGh/tVH4fKbGJb1QROrlgb7kFHR4cCKnIn1UZUS 8Mvs/UgPJ1NeYgbLbyvA2q0h42hvzb4c= 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-Archived-By: 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> X-Rspamd-Server: rspam06 X-Stat-Signature: hcnmnpu163i9cjdr4ngsijibdqex7g9h X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS autolearn=no autolearn_force=no version=4.0.1 X-Rspamd-Queue-Id: 031921C000D X-Rspam-User: X-HE-Tag: 1794397515-694799 X-HE-Meta: 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 IuGPq7gA Vie7HHouvEhXGsnJgXeKV2Uvl2TXIt+vlZFYCkm2TUX17IQmY406G0/EZwzKaKodFjTJiRi4QB0A34bnq38e1Dt+6+6MZAsFPWovaFomYI6PRSypq13sqoRLpSMa6525CeFi2byWiTFLx0uj9j3bTAqa3FGaWL9/JxTIeq+4E8drFJ/qGbBmFNjEGcYQIlMV/Gjod05ik5YscigXEx9DAiWwbw7jh4A2oxsvCKj+91VvJ+yPvma3pvqVyexYmqZTmCOE6+6KF4rg+Z4GfcxBJ8asQQU7VA/yWg2E1b7Cxt9UswBC8kmpM5755hHVteNUtn/f+QjgG5E5x0madK56fyjNnxf3Z48piN0PBtrXItMV7rFIF2VJVaSslO0B09YgM+iMj8Ts87ev/C3c0ybyUETrc/Q== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 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