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b=h9qY3ysQ0ie8RBLLbvg84OXV5EKQQR9D2zZjbIgXTYwqFEOarV5Pom2h6aQDS+joc mtP5ye5rHB5JxqXdC40G6sxfKaV8qD0a+8wdqYWAw36i8e5is9TJGt6ag0MXCm1mt8 Lc/eSGDTLBeg4MuxvgYbRUiq5MkFPju6wTx6k0SjS8oqq2eT//EVO5RF/kFWNkaWTe lGz+4ndG6+n+2ZINMdsmbYmEBijbZuetaxu8wB63cFto07iGcOGbr2V02O5DZPEax9 nYSYIilIFGx+atyNQV5Lv1TOi5wYX6roUQWGxbYqFpCuiBc3nxGK9O198eofZulYeI oNcfnjQdgCvKQ== Message-ID: <65cdc2fa-b6ba-4422-9537-feb7d3a33210@kernel.org> Date: Thu, 15 Jan 2026 21:22:28 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 0/8] Introduce a huge-page pre-zeroing mechanism To: dan.j.williams@intel.com, Jonathan Cameron Cc: Li Zhe , akpm@linux-foundation.org, ankur.a.arora@oracle.com, fvdl@google.com, joao.m.martins@oracle.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mhocko@suse.com, mjguzik@gmail.com, muchun.song@linux.dev, osalvador@suse.de, raghavendra.kt@amd.com, linux-cxl@vger.kernel.org, Davidlohr Bueso , Gregory Price , zhanjie9@hisilicon.com, wangzhou1@hisilicon.com References: <9daa39e6-9653-45cc-8c00-abf5f3bae974@kernel.org> <20260115093641.44404-1-lizhe.67@bytedance.com> <83798495-915b-4a5d-9638-f5b3de913b71@kernel.org> <20260115115739.00007cf6@huawei.com> <23513e86-0769-4f3f-b90b-22273343a03c@kernel.org> <69694b06835e_34d2a100b3@dwillia2-mobl4.notmuch> From: "David Hildenbrand (Red Hat)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 0041AC000C X-Rspam-User: X-Stat-Signature: 8uw6h7som9prf7myfbp4qt3mmzwfd5bs X-HE-Tag: 1768508555-705014 X-HE-Meta: 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 ODp5Vy8C DJCc/eX4r98k1RkkUC0Cj4ohhgKswPqxaWxz5tOWg+nlIhbL8TB3kVs/pP2Ju/KtltKx94OVvEQ0Ft61Npvx0dZlwGcE+VGSCmT4fH5wdfdvhsD+OaEEGTgP/7e4Tvb6BAqDPFcSfV0rWaupOou3bKqI/66dWwleT+EOoA17/ncVOqxBirBX/+CF5n882JaJbGvSJPP8vd0DHppJ2pYAIHcK8SaCye9DzXEi5fjQLQyOK3X/tlnT4ABgto9G3gg9sqW8ReOQYN+lDXICwiSxfK0WZOubS4BhLXU+T X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 1/15/26 21:16, dan.j.williams@intel.com wrote: > David Hildenbrand (Red Hat) wrote: > [..] >>> Give me a list of 1Gig pages and this stuff becomes much more efficient >>> than anything the CPU can do. >> >> Right, and ideally we'd implement any such mechanisms in a way that more >> parts of the kernel can benefit, and not just an unloved in-memory >> file-system that most people just want to get rid of as soon as we can :) > > CPUs have tended to eat the value of simple DMA offload operations like > copy/zero over time. > > In the case of this patch there is no async-offload benefit because > userspace is already charged with spawning more threads if it wants more > parallelism. In this subthread we're discussing handling that in the kernel like init_on_free. So when user space frees a hugetlb folio (or in the future, other similarly gigantic folios from another allocator), we'd be zeroing it. If it would be freeing multiple such folios, we could pack them and send them to a DMA engine to zero them for us (concurrently? asynchronously? I don't know :) ) -- Cheers David