From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E7E252882B7 for ; Thu, 8 Jan 2026 19:02:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767898946; cv=none; b=oWlhJ5eJTUqWVKl4ZpKoKmGDqHjxmepea3UKFDGRcn/XCvuCE5rBwpDidLQrDs/iZmi3FFx9QCIB+SYMqRfSWUQwR3jFcozdjmje4ysAyYFS31arUEDu4zsugctyIs56WrbOH1+tIHVcsAFL4Sb+ObINrBYkBuXS4Vr8Jodu5x0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767898946; c=relaxed/simple; bh=n7Z0aSYW5EnhtfO6BllhonTvJYl6V++1f2wg7c9H1Ys=; h=Date:To:From:Subject:Message-Id; b=kclBMSnkiyZJzus5wse/5pN2ggrSH2Wzk/ep7M7cGQ/z3UkP4TRocIc1X9LiZypHbm520RbdgPwIg3wdmC8gOp//pIwbNmomFPgij9Cw8sRcgZm+MLdqC9gNEFscjsWqfn6zQVQQJlDWMSoKoqqC5+KhtLisERhSjZdl+naqquI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=ph1IB+sj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="ph1IB+sj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 799D2C116C6; Thu, 8 Jan 2026 19:02:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1767898945; bh=n7Z0aSYW5EnhtfO6BllhonTvJYl6V++1f2wg7c9H1Ys=; h=Date:To:From:Subject:From; b=ph1IB+sjomPabI7ob1tU1mjCeV+I7eYpzJVMLuwYVDkYVZvW2H3uid24508OUMTeH 9EfQfpz6AlLTCj1Gga/0qhQtM3qqVxrWXPvMtFWf/3pTLILlG7FX7enh/xlldAcCuO pL/JCYeV3LciO3Eq8cL266WFQ5PVK2WANO4DruPs= Date: Thu, 08 Jan 2026 11:02:24 -0800 To: mm-commits@vger.kernel.org,zhengqi.arch@bytedance.com,yuanchu@google.com,weixugc@google.com,vbabka@suse.cz,surenb@google.com,shakeel.butt@linux.dev,rppt@kernel.org,rientjes@google.com,mhocko@kernel.org,lorenzo.stoakes@oracle.com,liam.howlett@oracle.com,jonathan.cameron@huawei.com,hannes@cmpxchg.org,david@kernel.org,axelrasmussen@google.com,akinobu.mita@gmail.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-numa_emu-add-document-for-numa-emulation.patch added to mm-new branch Message-Id: <20260108190225.799D2C116C6@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: numa_emu: add document for NUMA emulation has been added to the -mm mm-new branch. Its filename is mm-numa_emu-add-document-for-numa-emulation.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-numa_emu-add-document-for-numa-emulation.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Akinobu Mita Subject: mm: numa_emu: add document for NUMA emulation Date: Thu, 8 Jan 2026 19:15:34 +0900 Add a document with a brief explanation of numa emulation and how to use the newly added "numa_emulation.adistance=" kernel cmdline parameter. Link: https://lkml.kernel.org/r/20260108101535.50696-3-akinobu.mita@gmail.com Signed-off-by: Akinobu Mita Reviewed-by: Jonathan Cameron Cc: Axel Rasmussen Cc: David Hildenbrand Cc: David Rientjes Cc: Johannes Weiner Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Qi Zheng Cc: Shakeel Butt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Wei Xu Cc: Yuanchu Xie Signed-off-by: Andrew Morton --- Documentation/mm/index.rst | 1 Documentation/mm/numa_emulation.rst | 30 ++++++++++++++++++++++++++ 2 files changed, 31 insertions(+) --- a/Documentation/mm/index.rst~mm-numa_emu-add-document-for-numa-emulation +++ a/Documentation/mm/index.rst @@ -24,6 +24,7 @@ see the :doc:`admin guide <../admin-guid page_cache shmfs oom + numa_emulation Unsorted Documentation ====================== diff --git a/Documentation/mm/numa_emulation.rst a/Documentation/mm/numa_emulation.rst new file mode 100644 --- /dev/null +++ a/Documentation/mm/numa_emulation.rst @@ -0,0 +1,30 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============== +NUMA emulation +============== + +If CONFIG_NUMA_EMU is enabled, you can create fake NUMA nodes with +``numa=fake=`` kernel cmdline option. +See Documentation/admin-guide/kernel-parameters.txt and +Documentation/arch/x86/x86_64/fake-numa-for-cpusets.rst for more information. + + +Multiple Memory Tiers Creation +============================== + +The "numa_emulation.adistance=" kernel cmdline option allows you to set +the abstract distance for each NUMA node. + +For example, you can create two fake nodes, each in a different memory +tier by booting with "numa=fake=2 numa_emulation.adistance=576,704". +Here, the abstract distances of node0 and node1 are set to 576 and 706, +respectively. + +Each memory tier covers an abstract distance chunk size of 128. Thus, +nodes with abstract distances between 512 and 639 are classified into the +same memory tier, and nodes with abstract distances between 640 and 767 +are classified into the next slower memory tier. + +The abstract distance of fake nodes not specified in the parameter will +be the default DRAM abstract distance of 576. _ Patches currently in -mm which might be from akinobu.mita@gmail.com are mm-memory-tiers-numa_emu-enable-to-create-memory-tiers-using-fake-numa-nodes.patch mm-numa_emu-add-document-for-numa-emulation.patch mm-vmscan-dont-demote-if-there-is-not-enough-free-memory-in-the-lower-memory-tier.patch