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spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5B6B56B0538; Fri, 22 Nov 2019 19:54:16 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 567136B0539; Fri, 22 Nov 2019 19:54:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 455456B053A; Fri, 22 Nov 2019 19:54:16 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0235.hostedemail.com [216.40.44.235]) by kanga.kvack.org (Postfix) with ESMTP id 3130E6B0538 for ; Fri, 22 Nov 2019 19:54:16 -0500 (EST) Received: from smtpin04.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id C17708249980 for ; Sat, 23 Nov 2019 00:54:15 +0000 (UTC) X-FDA: 76185720870.04.duck13_41f4900168234 X-HE-Tag: duck13_41f4900168234 X-Filterd-Recvd-Size: 5453 Received: from hqemgate14.nvidia.com (hqemgate14.nvidia.com [216.228.121.143]) by imf36.hostedemail.com (Postfix) with ESMTP for ; Sat, 23 Nov 2019 00:54:13 +0000 (UTC) Received: from hqpgpgate101.nvidia.com (Not Verified[216.228.121.13]) by hqemgate14.nvidia.com (using TLS: TLSv1.2, DES-CBC3-SHA) id ; Fri, 22 Nov 2019 16:54:14 -0800 Received: from hqmail.nvidia.com ([172.20.161.6]) by hqpgpgate101.nvidia.com (PGP Universal service); Fri, 22 Nov 2019 16:54:11 -0800 X-PGP-Universal: processed; by hqpgpgate101.nvidia.com on Fri, 22 Nov 2019 16:54:11 -0800 Received: from rcampbell-dev.nvidia.com (172.20.13.39) by HQMAIL107.nvidia.com (172.20.187.13) with Microsoft SMTP Server (TLS) id 15.0.1473.3; Sat, 23 Nov 2019 00:54:09 +0000 Subject: Re: [PATCH v3 02/14] mm/mmu_notifier: add an interval tree notifier To: Jason Gunthorpe , Christoph Hellwig CC: "linux-mm@kvack.org" , Jerome Glisse , John Hubbard , "Felix.Kuehling@amd.com" , "linux-rdma@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "amd-gfx@lists.freedesktop.org" , Alex Deucher , Ben Skeggs , Boris Ostrovsky , =?UTF-8?Q?Christian_K=c3=b6nig?= , David Zhou , "Dennis Dalessandro" , Juergen Gross , Mike Marciniszyn , Oleksandr Andrushchenko , Petr Cvek , Stefano Stabellini , "nouveau@lists.freedesktop.org" , "xen-devel@lists.xenproject.org" , "Philip Yang" References: <20191112202231.3856-1-jgg@ziepe.ca> <20191112202231.3856-3-jgg@ziepe.ca> <20191113135952.GB20531@infradead.org> <20191113164620.GG21728@mellanox.com> X-Nvconfidentiality: public From: Ralph Campbell Message-ID: Date: Fri, 22 Nov 2019 16:54:08 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.0 MIME-Version: 1.0 In-Reply-To: <20191113164620.GG21728@mellanox.com> X-Originating-IP: [172.20.13.39] X-ClientProxiedBy: HQMAIL107.nvidia.com (172.20.187.13) To HQMAIL107.nvidia.com (172.20.187.13) Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nvidia.com; s=n1; t=1574470454; bh=bqXekT37QvQAiJj5unYfuv1fXYv5e9H7W3TE2f93DwM=; h=X-PGP-Universal:Subject:To:CC:References:X-Nvconfidentiality:From: Message-ID:Date:User-Agent:MIME-Version:In-Reply-To: X-Originating-IP:X-ClientProxiedBy:Content-Type:Content-Language: Content-Transfer-Encoding; b=RbJQdgYI/dFjAHVBUW2cZh29EsZO0NHYznPqb2KeSMvLVVy+04SbUd55RqBkrkhJI jm/LeQz23dcFfabHtr7RQD84s0QA8rh3fsS0PRa3IJS+eqYq7MGRwyq9H+zGaLMfD3 WqtNXVdcloKxtxdXWjpWt/eLYryP6nzidZyHs9Wc6z9xD5WKpR41oA1bXATTukQ9M6 1cHg0E2riIVQJmWnCM05nnbGLP5OMxPkcPPjqw6VP5O8mhO6Ety7S9I+GFqlFd653y +sAZHnWhqHkw9LpDWRh+68ed97cLbzYBVPI8EPpFZTzn7/Bdkz3mnORzqe8mUjddCf k/1CQ6pwn+MUg== 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 11/13/19 8:46 AM, Jason Gunthorpe wrote: > On Wed, Nov 13, 2019 at 05:59:52AM -0800, Christoph Hellwig wrote: >>> +int mmu_interval_notifier_insert(struct mmu_interval_notifier *mni, >>> + struct mm_struct *mm, unsigned long start, >>> + unsigned long length, >>> + const struct mmu_interval_notifier_ops *ops); >>> +int mmu_interval_notifier_insert_locked( >>> + struct mmu_interval_notifier *mni, struct mm_struct *mm, >>> + unsigned long start, unsigned long length, >>> + const struct mmu_interval_notifier_ops *ops); >> >> Very inconsistent indentation between these two related functions. > > clang-format.. The kernel config is set to prefer a line up under the > ( if all the arguments will fit within the 80 cols otherwise it does a > 1 tab continuation indent. > >>> + /* >>> + * The inv_end incorporates a deferred mechanism like >>> + * rtnl_unlock(). Adds and removes are queued until the final inv_end >>> + * happens then they are progressed. This arrangement for tree updates >>> + * is used to avoid using a blocking lock during >>> + * invalidate_range_start. >> >> Nitpick: That comment can be condensed into one less line: > > The rtnl_unlock can move up a line too. My editor is failing me on > this. > >>> + /* >>> + * TODO: Since we already have a spinlock above, this would be faster >>> + * as wake_up_q >>> + */ >>> + if (need_wake) >>> + wake_up_all(&mmn_mm->wq); >> >> So why is this important enough for a TODO comment, but not important >> enough to do right away? > > Lets drop the comment, I'm noto sure wake_up_q is even a function this > layer should be calling. Actually, I think you can remove the "need_wake" variable since it is unconditionally set to "true". Also, the comment in__mmu_interval_notifier_insert() says "mni->mr_invalidate_seq" and I think that should be "mni->invalidate_seq".