linux-kernel - Re: [PATCH] thp: Simplify splitting PMD mapping huge zero page

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] [day] [month] [year] [list]

Message-ID: <20200328001959.ggi74gch42soulus@box>
Date:   Sat, 28 Mar 2020 03:19:59 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Zi Yan <ziy@...dia.com>
Cc:     akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Subject: Re: [PATCH] thp: Simplify splitting PMD mapping huge zero page

On Fri, Mar 27, 2020 at 01:23:07PM -0400, Zi Yan wrote:
> On 27 Mar 2020, at 13:03, Kirill A. Shutemov wrote:
> 
> > Splitting PMD mapping huge zero page can be simplified a lot: we can
> > just unmap it and fallback to PTE handling.
> 
> So we will have an extra page fault for the first read to each subpage,
> but nothing changes if the first access to a subpage is a write, right?
> BTW, what is the motivation for this code simplification?

Match what we do for file-THP.

I found a problem with the patch. Ignore it for now.

-- 
 Kirill A. Shutemov