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a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1765808793; 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=g2AehqQR9213pHHieeF1GNopfJ0xN2gI7ajoegW6IhA=; b=MjOGgOJ1VDsdY6wjlVJfI7mspSgxi581OesWI7IhJNdc9306ICjHIXhM84Lb1Gwyjpibqh HGzO9rPbH5N1pkq/scBkhjM3dAwbexSaEIfc9R8Qff/b0LV/qzyJhSLSdYNmt5T+GbGRiN FQGJNwZnkRqsI5BtedU0LIn6/oYnwXg= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id BA60A600AC; Mon, 15 Dec 2025 14:26:32 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7090C4CEFB; Mon, 15 Dec 2025 14:26:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765808792; bh=vfRvfzjxtdoOanlAjTkNDBQHuuTEoetvAyA6tMfwKtg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=d9CBxFoF5yUM3zCJXEqAPWgC+jUV6COMMyPJU9KeU1hWsVQceZhkoOiyZTg+6hDXC hcHVnRfo10YzjQECcx5Tu1/turO+zG8GQ6iKeiqvwUPsW6sJCrdzTgOzhr8difjPoe J53dYsWhEV2U9TSb5QOkaKuAVz5ZuP855qv7tOQUFR3vu3OwYrfppG1AQYpVFcvs6q 4NF/25TiNogYlhFPYZ9GIAAhlJfM6uOxN+TPoMWXlHG5iPQ+9VvJ1hNNSud3eMY3Yd r1lsojsPUcf9RsUK/jI703+9jkgGzJP19m1AxQsaBJLUZAas8/y0buTSJx8eYO+Woi oAkrG+bwoYGTA== Message-ID: <5088b710-cfc5-417e-b629-c01d1eccb9b1@kernel.org> Date: Mon, 15 Dec 2025 15:26:25 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH next 0/2] THP COW support for private executable file mmap To: Matthew Wilcox , Zhang Qilong Cc: akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, corbet@lwn.net, ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, baohua@kernel.org, lance.yang@linux.dev, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, wangkefeng.wang@huawei.com, sunnanyong@huawei.com, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org References: <20251215123407.380813-1-zhangqilong3@huawei.com> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 6EF0140016 X-Stat-Signature: n9w68xbbf9os1usuh3exmhyu8as6j1gg X-Rspam-User: X-HE-Tag: 1765808793-57851 X-HE-Meta: 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 o8Qvn74T 84Wm7rT5pDqSJffE1wZeWFO4GRwn4HVJJ30l6wWuRqxN7sBTzsaYaXgAyoI5hFrrXK8M4MWvQ5WDwYgo6R3Dzg4/5vqpRVbF8z1/aY6XrJb1u7GJM95YXbve2MC6R/7TK6Eimq5t/rvRwLXoEteCqid+ehS2qV9Y2QJUpjYeZ1uISI9JsnCW/e6Bb9MG01lY78ujbTSLdwtpJtZVuGYbtVzOcMR56BUWhSZFga6oApwZgxwEE8mHnyWzAuJpMTnANd6dh 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 12/15/25 15:00, Matthew Wilcox wrote: > On Mon, Dec 15, 2025 at 08:34:05PM +0800, Zhang Qilong wrote: >> This patch series implementate THP COW for private executable file >> mmap. It's major designed to increase the iTLB cache hit rate for >> hot patching application, and we add a new sysfs knob to disable or >> enable it. > > You're going to have to provide data to get this patch in. We've > deliberately not done this in the past due to memory consumption overhead. > So you need to prove that's now the wrong decision to make. > > Microbenchmarks would be a bare minimum, but what are really needed are > numbers from actual workloads. In addition, the sysfs toggle is rather horrible. It's rather clear that this is not a system-wide setting to be made, as you likely only want that behavior (if at all ...) for a handful of special processes I assume? -- Cheers David