From nobody Mon Feb 9 07:43:16 2026 Received: from mail-yw1-f173.google.com (mail-yw1-f173.google.com [209.85.128.173]) (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 CE925319858 for ; Tue, 30 Dec 2025 14:53:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.173 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767106408; cv=none; b=ggZ3GnkQRfJsKIgYQpklvDC1Iu34sfxpVfmoMoFM3a7jcP1wr7qMQq5lcbh8LXCr8SljtrAUlh1Mx9wSmvAZFMTNL1JC+C0Pr2TJbMjO8So+xsAtisO2k/UNvhmzkuWn0pp9jIuypjEHAQWygHWsL2fQVk8zfQvOiiSZ6g2sWms= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767106408; c=relaxed/simple; bh=gi9KFSmk2b46NxhdBIDTjr0CUQbrcpnLpeSf3TsuCSE=; h=From:To:Subject:Date:Message-ID:MIME-Version; b=CIVk0mJyFl3pgvalZA2vUGz+HGegnZJrZeOUocFRzlhi7pF5YmqZD8y7vvqpRperB4ycfIoDP0oRiQd64/JUL78gztpMDxP65eCZEwxqHg/4Bj2YlSnwT1496nFzSzMdlwNY5q7oKJzBlAIGWN9sXZT6+NAmuWRJwh94OGfTDHk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=soleen.com; spf=pass smtp.mailfrom=soleen.com; dkim=pass (2048-bit key) header.d=soleen.com header.i=@soleen.com header.b=VwXn/+m/; arc=none smtp.client-ip=209.85.128.173 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) header.d=soleen.com header.i=@soleen.com header.b="VwXn/+m/" Received: by mail-yw1-f173.google.com with SMTP id 00721157ae682-78e7ba9fc29so88843467b3.2 for ; Tue, 30 Dec 2025 06:53:26 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; t=1767106406; x=1767711206; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:from:to:cc:subject:date:message-id:reply-to; bh=riYaqi0lArqEgWhtCeLrj3Qec2cHmyBPX4D058N2sx0=; b=VwXn/+m/a2+oY/rmkbh69Lkkj2EH+rA3R9wuwDqau9iLVLbnuQMooYnItl9xq7fy0e 09CXN/ra71YHW2EQIauZrXjKC5wpJ6o0jdNwfAtrtVN33kxnIwCDfEnLo1p7o3Xzr+0c vdrTvVW8lxyIdaVqsWk4qF8j60Y2H4Hh2aQLTgPRKouIqOxRgkrer2lNGD8Lb3iQXG9U Q+N96ix1xFOiEP/80vo4FXnrON/obyv2wNJNc2ENmx+a1tB9Si6EyCYWQOZ67lPipHvY FirhOQBhhMWK6WESY4Q2O5frs6A767RKL5KFGW5JoTJ9qEIDwIOGS7j2fPm4Qr8LcCw4 vtNA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767106406; x=1767711206; h=content-transfer-encoding:mime-version:message-id:date:subject:to :from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=riYaqi0lArqEgWhtCeLrj3Qec2cHmyBPX4D058N2sx0=; b=vp9lwL4gBHCQQcDR8KlV0tGqQgCB7ypa0amrAAHS/gx5Pdkia9mdYfHgSsKbcJrj86 WmqjXKJOazo0TcN1302e/ZIPN1eLictDnb4X37keH0hZcd2+whcSUfQB018ymrWWfeQV vZ4ujNGPExiJeodS0BkR9N00zuY/mOiGmXnO9tZyN7WwouXCRKlD1Yy08R0y9zXITm9t FDNnJHGLEBpFk8d2c6BkTgPPNc76lrFrnUnNzfTiloWkuo0BPb0L8jAd3YktHepg+mTN HlSEjcH13Mpndh26ne3NswmEPrHYgmNcOahxl1o1600ON6J8E9dxuiP8C83E5Jbu3tG2 irYQ== X-Forwarded-Encrypted: i=1; AJvYcCVURLUseraMrEF1KvUONvLT1XEPHDZkhNCAsjOYrYMJ8VopzzWUqt0i41fq2i9/qG456UQDXGmN2P+yJqk=@vger.kernel.org X-Gm-Message-State: AOJu0YwRf7Bxpk5MSrPQal2gSeD0ZdqNVWYxEAAla0af9mAUBBzryIww 9GTmZ0BQ+WnB6Z3Goi8kyFRdMl1sCKGzVEXqCev9V0LozSfDTiM62aLmdgPcVeswuWs= X-Gm-Gg: AY/fxX7X9Uv3WxCA3/jVeLbgKgaj73jKmI3hhQi8MXCyyqIzMw42FYAwykjK4F0wM8i L6QHO7sQwJW2c0lesBkopag8Guun8t/nJJRRcOSdtt/A3wJPpj52eIv7OeAsiz+JFuGSfJujIKe icDaBPeN4M7HKifJTdtrkX2J9YNdxLJsQgfHrPW+PVFMgcQ8M/wdkqoL788ipRY/IEax0vIVGzq aCAwhCJOc7R8A5xLH1rigc8J+zX6lsJu0rihLgUPm4QFnjFI1+81K8pfDwhw4kxceGPcMOCosDC bW6HstO1h0Fb7oIz69MMyWwq9cV/HAg+1tzPEQZozyj1BsjkdRHfCduFUrnqyD0VgKVGHqM9Mlf DFAGnJW8lKeFdk67YIsGQl+i9nn8V9PiON4RndMB73aQAkIdexgOCcX3QEG5U0IV8PEv46CgIaA CGTAKjbqyGTekTRhtISG+qNwEXekPOmdietQAQk0xWDgL9TureQUkITP/6PKrt+nKO0q4prLo7A 1hwv5JRDP4yYxTt3cSNUbl+4IjeJ94tZDTQTw== X-Google-Smtp-Source: AGHT+IG6aQUJXEtDcs/28NN3mbhDEeScCWUs9mOeS4mE4fbbBXX0Rzx0eSQVRgAfm6s+Ib5qJwPIPQ== X-Received: by 2002:a53:b549:0:b0:645:6c99:bf17 with SMTP id 956f58d0204a3-6466a8afe74mr22491541d50.52.1767106405631; Tue, 30 Dec 2025 06:53:25 -0800 (PST) Received: from soleen.c.googlers.com.com (182.221.85.34.bc.googleusercontent.com. [34.85.221.182]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-6466a8bd6ffsm16306220d50.9.2025.12.30.06.53.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Dec 2025 06:53:25 -0800 (PST) From: Pasha Tatashin To: akpm@linux-foundation.org, pasha.tatashin@soleen.com, rppt@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, pratyush@kernel.org Subject: [PATCH v2] liveupdate: separate memfd support into LIVEUPDATE_MEMFD Date: Tue, 30 Dec 2025 09:53:21 -0500 Message-ID: <20251230145321.1512630-1-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.52.0.351.gbe84eed79e-goog Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Decouple memfd preservation support from the core Live Update Orchestrator configuration. Previously, enabling CONFIG_LIVEUPDATE forced a dependency on CONFIG_SHMEM and unconditionally compiled memfd_luo.o. However, Live Update may be used for purposes that do not require memfd-backed memory preservation. Introduce CONFIG_LIVEUPDATE_MEMFD to gate memfd_luo.o. This moves the SHMEM and MEMFD_CREATE dependencies to the specific feature that needs them, allowing the base LIVEUPDATE option to be selected independently of shared memory support. Signed-off-by: Pasha Tatashin Reviewed-by: Pratyush Yadav --- Changes v2: - Updated testing config - Added review-by kernel/liveupdate/Kconfig | 16 +++++++++++++++- mm/Makefile | 2 +- tools/testing/selftests/liveupdate/config | 1 + 3 files changed, 17 insertions(+), 2 deletions(-) diff --git a/kernel/liveupdate/Kconfig b/kernel/liveupdate/Kconfig index d2aeaf13c3ac..9a1a8cdcf16c 100644 --- a/kernel/liveupdate/Kconfig +++ b/kernel/liveupdate/Kconfig @@ -54,7 +54,6 @@ config KEXEC_HANDOVER_ENABLE_DEFAULT config LIVEUPDATE bool "Live Update Orchestrator" depends on KEXEC_HANDOVER - depends on SHMEM help Enable the Live Update Orchestrator. Live Update is a mechanism, typically based on kexec, that allows the kernel to be updated @@ -73,4 +72,19 @@ config LIVEUPDATE =20 If unsure, say N. =20 +config LIVEUPDATE_MEMFD + bool "Live update support for memfd" + depends on LIVEUPDATE + depends on MEMFD_CREATE + depends on SHMEM + help + Enable live update support for memfd regions. This allows preserving + memfd-backed memory across kernel live updates. + + This can be used to back VM memory with memfds, allowing the guest + memory to persist, or for other user workloads needing to preserve + pages. + + If unsure, say N. + endmenu diff --git a/mm/Makefile b/mm/Makefile index 9175f8cc6565..798f04233d71 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -100,7 +100,7 @@ obj-$(CONFIG_NUMA) +=3D memory-tiers.o obj-$(CONFIG_DEVICE_MIGRATION) +=3D migrate_device.o obj-$(CONFIG_TRANSPARENT_HUGEPAGE) +=3D huge_memory.o khugepaged.o obj-$(CONFIG_PAGE_COUNTER) +=3D page_counter.o -obj-$(CONFIG_LIVEUPDATE) +=3D memfd_luo.o +obj-$(CONFIG_LIVEUPDATE_MEMFD) +=3D memfd_luo.o obj-$(CONFIG_MEMCG_V1) +=3D memcontrol-v1.o obj-$(CONFIG_MEMCG) +=3D memcontrol.o vmpressure.o ifdef CONFIG_SWAP diff --git a/tools/testing/selftests/liveupdate/config b/tools/testing/self= tests/liveupdate/config index 91d03f9a6a39..1bfc708041bd 100644 --- a/tools/testing/selftests/liveupdate/config +++ b/tools/testing/selftests/liveupdate/config @@ -5,6 +5,7 @@ CONFIG_KEXEC_HANDOVER_ENABLE_DEFAULT=3Dy CONFIG_KEXEC_HANDOVER_DEBUGFS=3Dy CONFIG_KEXEC_HANDOVER_DEBUG=3Dy CONFIG_LIVEUPDATE=3Dy +CONFIG_LIVEUPDATE_MEMFD=3Dy CONFIG_LIVEUPDATE_TEST=3Dy CONFIG_MEMFD_CREATE=3Dy CONFIG_TMPFS=3Dy --=20 2.52.0.351.gbe84eed79e-goog