From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 3EBF93DA7E5 for ; Fri, 24 Apr 2026 18:37:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777055823; cv=none; b=Fa36BgI5cf+ZIi4cMskvvhAEyxG75b/8Aury1/bHlIhoLb+e8Kdi/FbRqT/zOrptnESbl3ipuPuS3tpn9C81n2BE2OLfYN4ywdIiR7arOOJPtkdyKn7YExbfhZREQh0n9edNmXc+u120fVqSVb9+ypOErT4Buf1Kt2MRvrSHrus= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777055823; c=relaxed/simple; bh=X3unbKjXkfIxpZgPYPCXBXdaO16pNyP21Y+UN+3Q6ys=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=kGU10si2wYxO6d0VVutbne/QoxiEBAixyvaMIcpZmZyVTSntSSK0ZqLnIS5eZuK47A9THJ2Dyx8yM8Pxf/CrkhMbSX1MH4Ir8zrWFYXAWA7f3K0Lj6muHNh0oKRR9wB7HG46OFEZ5hMnLQ6O6vP1D/y3J9+yuTXYPFSVFhOykug= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=cMOERr44; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=VmoZwR+8; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cMOERr44"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="VmoZwR+8" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1777055821; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=EzZh79GGJvnyX3o1poX9T4TAY2qDXkiWPDaOxeNq0iQ=; b=cMOERr44959ZKRtT3iBHg1lbI744oSBkdhPb6bH876rwyvwlcs/3sWkwSTuc/+Sc9Tbjua 7XyVT3aloxXpaUiu7bdJxud1uvsxqpAot++XlYyPHWaOyFArErNp3tIZr5xzVvfnA7CDdy M/cPSaEQRt7/EUAA6fTXtAFUnW4EXF8= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-70-MUmPpBY_MH6X5rKY6NgZGg-1; Fri, 24 Apr 2026 14:37:00 -0400 X-MC-Unique: MUmPpBY_MH6X5rKY6NgZGg-1 X-Mimecast-MFC-AGG-ID: MUmPpBY_MH6X5rKY6NgZGg_1777055818 Received: by mail-wm1-f70.google.com with SMTP id 5b1f17b1804b1-4837bfcfe0dso88514845e9.1 for ; Fri, 24 Apr 2026 11:36:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1777055818; x=1777660618; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=EzZh79GGJvnyX3o1poX9T4TAY2qDXkiWPDaOxeNq0iQ=; b=VmoZwR+8qNCS5ayDiD8bEvlao+vNn22bv9z5IBWm0nX95FjA+oYnMLKlYgxJgEAWOs 0tCcUGfG/6OsH4yqKlJAYBVdObPA+wj0jlBOSaf+I6ei0RL8MlPbsWv4k3yeq6qRBX6m jDwcaqF4+xbdKSEjRoBfl4CLwXYe7mcfuWnY+QKg4gCoAVMJJiR5qReIT/o3kE5oy0UC rBuv/jr6Vzcz5C9bLTzeJHjAgPUVK8L6F6L5XvtV2Y4OoXCy/VBMKc9p5Xv21RpPbcrG tGvIkzLhHiYxWPqA0x4V4td2KofSd0C8RqxJxVc1sZEFTvi3hSVvncl+JMb5deYw78BB X26w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1777055818; x=1777660618; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-gg:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=EzZh79GGJvnyX3o1poX9T4TAY2qDXkiWPDaOxeNq0iQ=; b=eNAK2X2I1VzeuRwouNtDOAtBgz+42MgrJvbVfe3y8OIpB8RXw7WLls9gFfdINecqjU VrHnxdcGOCQchDrl4HOCchgP6eSU5XWenb+2eJRi7dV6L05PPCgMUO8oixDBenu6fulD Fo4LkpFXit3AQbF4TgKvUNJb5UpQ9drcx2AnpmLTyV8r6VPUXOzOBsHenFsXI+Bjc0Yb CL/k6HOavZoYtdnOIluMHLcvkWRoY/7EwL3j/nDuD6kEdw0sN8mpMnUjw4s/pq4QyWG3 q+RlSPn0KifZ6lJGLQWZNnW7pY0iYC+tK22roEfKCJ75OIZvwJU6zo+rk96j2rAqJ6pV jMMg== X-Forwarded-Encrypted: i=1; AFNElJ/eyM62PfzTEg3s1x1HEeL/4Ppcus+VgfNtsHC3RRc860XOrKKcGhbH/ujTmmUsjqMzbXEpY0ZzxxwN1+Hl@vger.kernel.org X-Gm-Message-State: AOJu0YxU7qrfgx9BX7LcGSudM4SqEpWxKENpJ70B/bzA/x757Z4/dHES et1W2m6OGQAjD1c6qb7RCNHqhGxXyutvET5Hhdac/VdKI1uyRKJINyEoBN1FkPIxTQUisbt12PL q978SptWgDlARtuZiBe57H4JO8CR7cqklHqcEtsr65ylVAZkb87cCP8R+F+4vrRhzFtE= X-Gm-Gg: AeBDieudAOlnXtQzNzeStk5zOJCgk7ND5OwE4oI5sxE9Uh5h8BY+ceJDvNRyjk6IiRl 7XQkKaG7tBmv/fIlcz8+9SVkja74h1eFk7l8nEnXRYWIG9LrZP86p+1hqLc2Ej0g32KfG8aVo0Z XeVb1xb3wlwHYQYX34hPgZQKOQIBjVkZYh+V+0KNGDo1Ery9s0FCMxaUYqddJ1rOiJ4Y0leLmT1 hyORwXxbV7A2M/XOE3XJlUDofFg0FCBmz4mPbFbv+tlSrLbpnxtCotTDsXM58Yl+n+Lzczw+cCk nELpl2TqLsvIuxz51YYmZyYBMMVlQRwtYkc9QlHHUTd7NHl0bz+rPMOrPk5T63HeKlR2ySFzJap 3IHx9oXNp/O8RTdAh+y1ZvWDcoEEjTPVuyZoHBMSIFSXPxMZMOys2O/cYECDz9HU= X-Received: by 2002:a05:600c:5295:b0:485:30d4:6b9e with SMTP id 5b1f17b1804b1-488fb77facemr466165675e9.21.1777055817632; Fri, 24 Apr 2026 11:36:57 -0700 (PDT) X-Received: by 2002:a05:600c:5295:b0:485:30d4:6b9e with SMTP id 5b1f17b1804b1-488fb77facemr466165305e9.21.1777055817177; Fri, 24 Apr 2026 11:36:57 -0700 (PDT) Received: from redhat.com (bzq-79-177-155-147.red.bezeqint.net. [79.177.155.147]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a55dc9f58sm607291535e9.6.2026.04.24.11.36.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 24 Apr 2026 11:36:56 -0700 (PDT) Date: Fri, 24 Apr 2026 14:36:51 -0400 From: "Michael S. Tsirkin" To: "David Hildenbrand (Arm)" Cc: Gregory Price , linux-kernel@vger.kernel.org, Andrew Morton , Vlastimil Babka , Brendan Jackman , Michal Hocko , Suren Baghdasaryan , Jason Wang , Andrea Arcangeli , linux-mm@kvack.org, virtualization@lists.linux.dev, Johannes Weiner , Zi Yan , Lorenzo Stoakes , "Liam R. Howlett" , Mike Rapoport , "Matthew Wilcox (Oracle)" , Muchun Song , Oscar Salvador , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Ying Huang , Alistair Popple , Hugh Dickins , Christoph Lameter , David Rientjes , Roman Gushchin , Harry Yoo , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , linux-fsdevel@vger.kernel.org Subject: Re: [PATCH RFC v3 01/19] mm: thread user_addr through page allocator for cache-friendly zeroing Message-ID: <20260424143541-mutt-send-email-mst@kernel.org> References: <20260422171315-mutt-send-email-mst@kernel.org> <20260423074433-mutt-send-email-mst@kernel.org> <88b0765f-7cfc-4e44-83d2-c01a1755c842@kernel.org> <20260423104120-mutt-send-email-mst@kernel.org> <1ab6e58f-d984-4bae-a343-1b0d3c973ad0@kernel.org> <20260423121222-mutt-send-email-mst@kernel.org> <4e12d67b-60e3-4bf5-a229-43c0d2c62cfb@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4e12d67b-60e3-4bf5-a229-43c0d2c62cfb@kernel.org> On Fri, Apr 24, 2026 at 08:33:45PM +0200, David Hildenbrand (Arm) wrote: > On 4/23/26 18:13, Michael S. Tsirkin wrote: > > On Thu, Apr 23, 2026 at 05:54:26PM +0200, David Hildenbrand (Arm) wrote: > >> On 4/23/26 16:46, Michael S. Tsirkin wrote: > >>> > >>> I just dislike it when things are non orthogonal. > >>> People are used to: hugetlb = same perf as THP but more predictable at the cost > >>> of being harder to use and using more resources. > >>> Here, suddenly, we have an optimization but only for THP. > >> > >> Note that we also didn't care about user_alloc_needs_zeroing() with hugetlb so far. > > > > > > You mean, that it stays because of the reserved pool? > > I meant, that if we are running with init_on_free or init_on_alloc, that we end > up double-zeroing right now upstream. So nobody cared to optimize that part so far. on the aliasing arches you mean? that double zeroing? > -- > Cheers, > > David