linux-kernel - Re: [PATCH v3 3/6] mm: support THP migration to device private memory

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <0ed2fbec-e855-9be5-4897-523b00391a5a@nvidia.com>
Date:   Mon, 9 Nov 2020 13:34:17 -0800
From:   Ralph Campbell <rcampbell@...dia.com>
To:     Christoph Hellwig <hch@....de>
CC:     <linux-mm@...ck.org>, <nouveau@...ts.freedesktop.org>,
        <linux-kselftest@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Jerome Glisse" <jglisse@...hat.com>,
        John Hubbard <jhubbard@...dia.com>,
        "Alistair Popple" <apopple@...dia.com>,
        Jason Gunthorpe <jgg@...dia.com>,
        Bharata B Rao <bharata@...ux.ibm.com>,
        Zi Yan <ziy@...dia.com>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Yang Shi <yang.shi@...ux.alibaba.com>,
        Ben Skeggs <bskeggs@...hat.com>, Shuah Khan <shuah@...nel.org>,
        "Andrew Morton" <akpm@...ux-foundation.org>
Subject: Re: [PATCH v3 3/6] mm: support THP migration to device private memory


On 11/9/20 1:14 AM, Christoph Hellwig wrote:
> On Fri, Nov 06, 2020 at 01:26:50PM -0800, Ralph Campbell wrote:
>>
>> On 11/6/20 12:03 AM, Christoph Hellwig wrote:
>>> I hate the extra pin count magic here.  IMHO we really need to finish
>>> off the series to get rid of the extra references on the ZONE_DEVICE
>>> pages first.
>>
>> First, thanks for the review comments.
>>
>> I don't like the extra refcount either, that is why I tried to fix that up
>> before resending this series. However, you didn't like me just fixing the
>> refcount only for device private pages and I don't know the dax/pmem code
>> and peer-to-peer PCIe uses of ZONE_DEVICE pages well enough to say how
>> long it will take me to fix all the use cases.
>> So I wanted to make progress on the THP migration code in the mean time.
> 
> I think P2P is pretty trivial, given that ZONE_DEVICE pages are used like
> a normal memory allocator.  DAX is the interesting case, any specific
> help that you need with that?

Thanks for the offer. I'm putting a list together... :-)