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[216.228.121.143]) by mx.google.com with ESMTPS id b4si695368pls.231.2019.03.28.19.05.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 28 Mar 2019 19:05:22 -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=FRvCg0fM; 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 19:05:25 -0700 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Thu, 28 Mar 2019 19:05:22 -0700 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Thu, 28 Mar 2019 19:05:22 -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 02:05:21 +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 , Ben Skeggs CC: Ira Weiny , , , Andrew Morton , Dan Williams References: <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> <20190329014259.GD16680@redhat.com> <20190329015919.GF16680@redhat.com> From: John Hubbard Message-ID: Date: Thu, 28 Mar 2019 19:05:21 -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: <20190329015919.GF16680@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: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1553825125; bh=+1O9YpiNfEVCCc+AeXkWqW7U0Khy1QDft89NTnXa5GY=; h=X-PGP-Universal:Subject:To:CC:References:From:Message-ID:Date: User-Agent:MIME-Version:In-Reply-To:X-Originating-IP: X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=FRvCg0fME4TeQCUKe5tlbRFfjI9Gn+fL4I/dhgs3fcXV6xp3Bc1c8DDtPW/Opm+nb ae6YdMCZGFdkBREzXTd6995PTV+YFxEMWfQ5JbJkcFTibqmpasyWda4MuxekUso0Dw GV4Gw0twubnHa5WN4YG413vAcrTP7YSnkTqJRS6q2UrKUq7IEhq21G0OLwgeW/73uI ZnDXrV1pgRtf8m83kzsqcTuBgSsvwGgCM507T4p7cW53J71HhOQOoRpXMDZ3fkBYbE yDSEpTSfDqkJodqYtcnYAC0vFdVebPl88NFleKIe26mGoF9ZRhYq3W0u8SUeiNQbyb +8E48ZXB/twoA== 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 6:59 PM, Jerome Glisse wrote: >>>>>> [...] >>>>> 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 would >>>>> have shortened the discussion here. >>>>> >>>> >>>> That helper is also use today by nouveau so changing that name is not that >>>> easy it does require the multi-release dance. So i am not sure how much >>>> value there is in a name change. >>>> >>> >>> 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 something >>> that effectively does not allow any minor changes! >>> >>> I do think it's worth some *minor* trouble to improve the name, assuming that we >>> can do it in a simple patch, rather than some huge maintainer-level effort. >> >> Change to nouveau have to go through nouveau tree so changing name means: Yes, I understand the guideline, but is that always how it must be done? Ben (+cc)? >> - release N add function with new name, maybe make the old function just >> a wrapper to the new function >> - release N+1 update user to use the new name >> - release N+2 remove the old name >> >> So it is do-able but it is painful so i rather do that one latter that now >> as i am sure people will then complain again about some little thing and it >> will post pone this whole patchset on that new bit. To avoid post-poning >> RDMA and bunch of other patchset that build on top of that i rather get >> this patchset in and then do more changes in the next cycle. >> >> This is just a capacity thing. > > Also for clarity changes to API i am doing in this patchset is to make > the ODP convertion easier and thus they bring a real hard value. Renaming > those function is esthetic, i am not saying it is useless, i am saying it > does not have the same value as those other changes and i would rather not > miss another merge window just for esthetic changes. > Agreed, that this minor point should not hold up this patch. thanks, -- John Hubbard NVIDIA