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[216.228.121.143]) by mx.google.com with ESMTPS id i96si634032plb.322.2019.03.28.18.30.27 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 28 Mar 2019 18:30:28 -0700 (PDT) Received-SPF: pass (google.com: domain of jhubbard@nvidia.com designates 216.228.121.143 as permitted sender) client-ip=216.228.121.143; Authentication-Results: mx.google.com; dkim=pass header.i=@nvidia.com header.s=n1 header.b=XsyhN1AS; spf=pass (google.com: domain of jhubbard@nvidia.com designates 216.228.121.143 as permitted sender) smtp.mailfrom=jhubbard@nvidia.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=nvidia.com Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Thu, 28 Mar 2019 18:30:31 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Thu, 28 Mar 2019 18:30:27 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Thu, 28 Mar 2019 18:30:27 -0700 Received: from [10.110.48.28] (10.124.1.5) by HQMAIL101.nvidia.com (172.20.187.10) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Fri, 29 Mar 2019 01:30:27 +0000 Subject: Re: [PATCH v2 07/11] mm/hmm: add default fault flags to avoid the need to pre-fill pfns arrays. To: Jerome Glisse , Ira Weiny CC: , , Andrew Morton , Dan Williams References: <20190325144011.10560-1-jglisse@redhat.com> <20190325144011.10560-8-jglisse@redhat.com> <2f790427-ea87-b41e-b386-820ccdb7dd38@nvidia.com> <20190328221203.GF13560@redhat.com> <555ad864-d1f9-f513-9666-0d3d05dbb85d@nvidia.com> <20190328223153.GG13560@redhat.com> <768f56f5-8019-06df-2c5a-b4187deaac59@nvidia.com> <20190328232125.GJ13560@redhat.com> <20190328164231.GF31324@iweiny-DESK2.sc.intel.com> <20190329011727.GC16680@redhat.com> From: John Hubbard X-Nvconfidentiality: public Message-ID: Date: Thu, 28 Mar 2019 18:30:26 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.3 MIME-Version: 1.0 In-Reply-To: <20190329011727.GC16680@redhat.com> X-Originating-IP: [10.124.1.5] X-ClientProxiedBy: HQMAIL101.nvidia.com (172.20.187.10) To HQMAIL101.nvidia.com (172.20.187.10) Content-Type: text/plain; charset="utf-8" Content-Language: en-US-large Content-Transfer-Encoding: quoted-printable DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1553823031; bh=6CXtjATayMacxoWaowYhZ6ypW2hRAvedqZ7XljR3NP0=; h=X-PGP-Universal:Subject:To:CC:References:From:X-Nvconfidentiality: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=XsyhN1ASj7Mh0dDwxw0mXugftAbLLQTdnDmNNouB6FlcjokJuiLocsVpdmB9T5dRX gFx9TMvi/rO2wQxXKYSR8WOjn2ecwn5VPScbRdlKs2x5NsBv7OfY0TahE7GONGQbfy TTdcfBqRqMi+lJFwenppTHbUAaOtBheAuOKSPSRC1lXbiIldfu8TVUFrKHRif+Fc0K Xh74rfxCYL7J5SAWbmORiJ+84PE0+BkROLxMfI/pGxBriWk9wZyVnUhOSZAIz5xA6I SL9NXQReFHiluHxyoqW5SlqBlYT+nkX6PHfMKQGmElYqgvnS4eyVM1Q+mmv4TyhU6J WrI1cKMY+F4dg== 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: On 3/28/19 6:17 PM, Jerome Glisse wrote: > On Thu, Mar 28, 2019 at 09:42:31AM -0700, Ira Weiny wrote: >> On Thu, Mar 28, 2019 at 04:28:47PM -0700, John Hubbard wrote: >>> On 3/28/19 4:21 PM, Jerome Glisse wrote: >>>> On Thu, Mar 28, 2019 at 03:40:42PM -0700, John Hubbard wrote: >>>>> On 3/28/19 3:31 PM, Jerome Glisse wrote: >>>>>> On Thu, Mar 28, 2019 at 03:19:06PM -0700, John Hubbard wrote: >>>>>>> On 3/28/19 3:12 PM, Jerome Glisse wrote: >>>>>>>> On Thu, Mar 28, 2019 at 02:59:50PM -0700, John Hubbard wrote: >>>>>>>>> On 3/25/19 7:40 AM, jglisse@redhat.com wrote: >>>>>>>>>> From: J=C3=A9r=C3=B4me Glisse >>> [...] >> Indeed I did not realize there is an hmm "pfn" until I saw this function= : >> >> /* >> * hmm_pfn_from_pfn() - create a valid HMM pfn value from pfn >> * @range: range use to encode HMM pfn value >> * @pfn: pfn value for which to create the HMM pfn >> * Returns: valid HMM pfn for the pfn >> */ >> static inline uint64_t hmm_pfn_from_pfn(const struct hmm_range *range, >> unsigned long pfn) >> >> So should this patch contain some sort of helper like this... maybe? >> >> I'm assuming the "hmm_pfn" being returned above is the device pfn being >> discussed here? >> >> I'm also thinking calling it pfn is confusing. I'm not advocating a new= type >> but calling the "device pfn's" "hmm_pfn" or "device_pfn" seems like it w= ould >> have shortened the discussion here. >> >=20 > That helper is also use today by nouveau so changing that name is not tha= t > easy it does require the multi-release dance. So i am not sure how much > value there is in a name change. >=20 Once the dust settles, I would expect that a name change for this could go via Andrew's tree, right? It seems incredible to claim that we've built som= ething that effectively does not allow any minor changes! I do think it's worth some *minor* trouble to improve the name, assuming th= at we can do it in a simple patch, rather than some huge maintainer-level effort. This field name not a large thing, but the cumulative effect of having a nu= mber of naming glitches within HMM is significant. The size and complexity of HMM h= as always made it hard to attract code reviewers, so let's improve what we can= , to counteract that. thanks, --=20 John Hubbard NVIDIA