From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22FF3C04A94 for ; Mon, 31 Jul 2023 19:23:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229637AbjGaTXi (ORCPT ); Mon, 31 Jul 2023 15:23:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54818 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229537AbjGaTXf (ORCPT ); Mon, 31 Jul 2023 15:23:35 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 165111BC5 for ; Mon, 31 Jul 2023 12:22:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1690831351; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=3XHpXZQfPdcBCB40xD4cQo5HE4yndD5B/+tRyE4teEw=; b=VQAdpjcAeN6YItaZAm5NoKnli4N0JB5kcuBz2IoiPSgZMfTyRC5UGRMsfMbwWOTCAf6cyM 8KRWfa3VpYcar5nlCIwpXKhLQ9AT8VBnqqxWeHuOfhoqkszqdiGAbD/6EtlAGMYnRjycLM 34NJ0iFZkGis9Gx7uWbOEf8lLCYQ4sM= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-264-1GyVyPnDMXylJRZAX9HgyQ-1; Mon, 31 Jul 2023 15:22:29 -0400 X-MC-Unique: 1GyVyPnDMXylJRZAX9HgyQ-1 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-3fe25f8c4bfso3230625e9.2 for ; Mon, 31 Jul 2023 12:22:29 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690831348; x=1691436148; h=content-transfer-encoding:in-reply-to:subject:organization:from :references:cc:to:content-language:user-agent:mime-version:date :message-id:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=3XHpXZQfPdcBCB40xD4cQo5HE4yndD5B/+tRyE4teEw=; b=ZoAmmtLkt68H+KD6Ozg0+vAdPCqQ4iaHkwC50W4Ga0wUIQXAmX2sWZnFmDJ6LjWpeP xqnAPYn2Zvk/7IdYvJzMiEyoZcinCSnTKCjmBtP3iK9bDVGlqaTRcQ9I402FWLCV+sTd zAPhfJ0hG78Zqy0j9Y7+Zgk2urMcZv3fClnNdAWcLq6AfKa7Tu1pXvBbVjVXvmxgAvCs ytXG5cM+oV9U72aJgPB3c5xAfWo/ZX9y+slz+wh3E3t4LHshubxigP0C138GAqvFp//B VgWIadCzVpz8Pcnbvd2wLqh9Wz+Ls/J+fXAe8oN3QeV8HlvDnxzpLLKvoUZ/rx5q0kkr OwNg== X-Gm-Message-State: ABy/qLYgLy1WIz2CoPNG9e4GmINpcXaFOcLn3Wq37k36AauChTi1nQHY 9Xo8zbikwgCyiin9/b4AH4HtASS2LnupGT/8um8q/yvHB8uYn7cSWMhe9A12xAYQG9s278+luHz nbbiWl5GSGw2fByZnmm5J5lun X-Received: by 2002:a5d:5389:0:b0:313:ea59:7ded with SMTP id d9-20020a5d5389000000b00313ea597dedmr527975wrv.24.1690831348687; Mon, 31 Jul 2023 12:22:28 -0700 (PDT) X-Google-Smtp-Source: APBJJlE3VWK9O6PVe8wtmdproWt76/+jiswldybLURzUXx9vkkftywxOeU5n+v/yJOUJccBkcxNCsQ== X-Received: by 2002:a5d:5389:0:b0:313:ea59:7ded with SMTP id d9-20020a5d5389000000b00313ea597dedmr527965wrv.24.1690831348285; Mon, 31 Jul 2023 12:22:28 -0700 (PDT) Received: from ?IPV6:2003:cb:c723:4c00:5c85:5575:c321:cea3? (p200300cbc7234c005c855575c321cea3.dip0.t-ipconnect.de. [2003:cb:c723:4c00:5c85:5575:c321:cea3]) by smtp.gmail.com with ESMTPSA id i15-20020adffdcf000000b003145559a691sm13875824wrs.41.2023.07.31.12.22.27 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 31 Jul 2023 12:22:27 -0700 (PDT) Message-ID: <9a26ce23-9ac7-b111-b700-db0905203c73@redhat.com> Date: Mon, 31 Jul 2023 21:22:26 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Content-Language: en-US To: Linus Torvalds Cc: Peter Xu , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Andrew Morton , liubo , Matthew Wilcox , Hugh Dickins , Jason Gunthorpe , John Hubbard , Mel Gorman References: <20230727212845.135673-1-david@redhat.com> <412bb30f-0417-802c-3fc4-a4e9d5891c5d@redhat.com> <66e26ad5-982e-fe2a-e4cd-de0e552da0ca@redhat.com> From: David Hildenbrand Organization: Red Hat Subject: Re: [PATCH v1 0/4] smaps / mm/gup: fix gup_can_follow_protnone fallout In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 31.07.23 21:07, Linus Torvalds wrote: > On Mon, 31 Jul 2023 at 12:00, David Hildenbrand wrote: >> >> So in the "!writable" case, we would always call >> get_user_pages_unlocked() and never honor NUMA faults. > > Ok, so kvm doesn't just use the fast version. Oh well. It was an idea.. Certainly an interesting one, thanks for thinking about possible alternatives! Unfortunately, KVM is an advanced GUP user to managed secondary MMUs. I'll get the FOLL_HONOR_NUMA_FAULT patches ready tomorrow and we can discuss if that looks better. (btw, the whole reasoning about "HW would refuse to use these pages" was exactly the whole reason I went into the FOLL_FORCE direction ... but it's really better to make FOLL_FORCE deal with VMA protection only) -- Cheers, David / dhildenb