From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 57CEF3E5EDC for ; Fri, 24 Apr 2026 18:37:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777055822; cv=none; b=BayafU7KQ2aGnt/P6OODdQrQ3kPFuF+8bcyLfqdo3JXA33N/wYOoglzQAHHYzIDwKTprd/5/26T96niVDlHX3aeRIxVunHp9AynY/sXx1UycEKjhU6nIO49LVDK/O6GJE8v70U6TDTo92iCyahUAKu0joPKMT+yPz864fa5sXiU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777055822; 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=Zm5+ZlMkg3tYU9u6v0jSA27cagnF5k4huBrJmzTXbrbuaDMhehl1uCB2by+m5Q30PcTq7rKS2xdY1v5aaYhGvCBDBVGt3lYOp1kvdWhmhfHX2dqmqrOJnxEitoU49SjYs6MWQs3Y03ufSbdiMCkkqh7g6+z+bORKlQBaM3XF4VE= 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=STTTpKqo; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=VmoZwR+8; arc=none smtp.client-ip=170.10.129.124 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="STTTpKqo"; 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=1777055820; 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=STTTpKqoKX4dRxVofCHrXYi6S6AHgT+1MpsfipFKxYHl6RyznZW/BbgJiD/qGAnOmU0mST 5iBt0fRY+3HssjowDnqF4R3mKkUnaF665MKhBNHQTZItict4AnH40H92vListX96Sgdhr2 d7VuNMf05gv1j+HRIuNPPd1KvZa1CJc= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-445-Ft3bep1EOkKv3OY41wzZJw-1; Fri, 24 Apr 2026 14:36:59 -0400 X-MC-Unique: Ft3bep1EOkKv3OY41wzZJw-1 X-Mimecast-MFC-AGG-ID: Ft3bep1EOkKv3OY41wzZJw_1777055818 Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-488c2aa6becso74307825e9.2 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=ZZpSRRMdTVTF6cArC/fR9HCRfy1E6Tz5uss93YZgE2Ur3UpqjenGuUF5C5pcHwayPZ OgiY3mu7TD4qyQwNnELm2d2S096dyx4dDlz5t5OC3REGMmKIgKMiSKpIBK3z1JAhXkfa 1IVNYJAlXYQQjv1Nc2RZawr/iIoIwK1weStkUrOi6RQ+V4LcjUMncnKbSIuCcboNhHzu CYqaHsA05WNWQJA7tsZ/9UfHtTu2yxSw0HuOUj0qShdMh7lLQf3Rrt/Ph7U3JVyCYq61 PEleaVx0quNrfEMsDNjB89bzb49ak2/x3+ysSILHsdN4ZhkcdmtpRm+B3T2V5AicqOe8 H0pQ== X-Forwarded-Encrypted: i=1; AFNElJ9oJoOTPCzGDhmzkkF6DPqp7oqpIYnkrjHNWRRnpY7sOxoyVxJvyf/l02kSzGVKtJHDeX3763IorAz18+o=@vger.kernel.org X-Gm-Message-State: AOJu0YwyA7tH6R4253GJ174KAVq/FYyxDKdkZFxYFDI+AMXTrfOel826 tWyzo4/bqtmZGvApntdjCFzgAmm1y1HK6zZP1pstdWRrMzU70e0A1cA4twpxmV1mZxmz8z+i1pu xn+iEHC+VNNMjmPrpBBMzz4JI794emf/ZDROwuD05DILJpPUnoaflcvJLtbr7Infg+Q== X-Gm-Gg: AeBDieuPoa3ZblGeLMQ/4KuqS2v3DO3DsxxDhBfkxPeobfu3dfP0rJke+IMjUaDM0tY AO1a8LguGsM2fQNIdf7wBk4XvIa4czEs6y8MJ63X0ddOWsqVph+Zw/ozCsSSo3AhWcoMGNL5cKT P05c5ObarUpJv1MyMT+SbMCkU8+LksQchLf+e6YwCCQN+KJoeQWIiAFEb07g28xLDVzsMkqcxzM 0xRdaCPj2iQD9k5fmQJMnqvt9rp4MIYYivkFTY0e7i7HaWmm0lT94HPeXvmi1VE67DUCiLwKqCl F5jn1Ucc/QVVK0pb1+HgX9uw8M7JSlL9yaacYHuuk+DvJ2//eZd7kBQ4QWh0gijqwRBKZayYYzn ql2/JnIqD3hMzCgAbHZS9RMyCDAcbF+ZX6rd1+40XR/2grU5PdsYjf1Fd9CyfUR8= X-Received: by 2002:a05:600c:5295:b0:485:30d4:6b9e with SMTP id 5b1f17b1804b1-488fb77facemr466165665e9.21.1777055817632; 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-kernel@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