linux-kernel - Re: [RFC PATCH 00/16] 1GB THP support on x86

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: <20200902184852.GH24045@ziepe.ca>
Date:   Wed, 2 Sep 2020 15:48:52 -0300
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     Zi Yan <ziy@...dia.com>
Cc:     linux-mm@...ck.org, Roman Gushchin <guro@...com>,
        Rik van Riel <riel@...riel.com>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        Matthew Wilcox <willy@...radead.org>,
        Shakeel Butt <shakeelb@...gle.com>,
        Yang Shi <yang.shi@...ux.alibaba.com>,
        David Nellans <dnellans@...dia.com>,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH 00/16] 1GB THP support on x86_64

On Wed, Sep 02, 2020 at 02:45:37PM -0400, Zi Yan wrote:

> > Surprised this doesn't touch mm/pagewalk.c ?
> 
> 1GB PUD page support is present for DAX purpose, so the code is there
> in mm/pagewalk.c already. I only needed to supply ops->pud_entry when using
> the functions in mm/pagewalk.c. :)

Yes, but doesn't this change what is possible under the mmap_sem
without the page table locks?

ie I would expect some thing like pmd_trans_unstable() to be required
as well for lockless walkers. (and I don't think the pmd code is 100%
right either)

Jason