linux-kernel - Re: [RFC PATCH 0/7] mm: Get rid of vmalloc_sync

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: <20200508213609.GU8135@suse.de>
Date:   Fri, 8 May 2020 23:36:09 +0200
From:   Joerg Roedel <jroedel@...e.de>
To:     Andy Lutomirski <luto@...nel.org>
Cc:     Joerg Roedel <joro@...tes.org>, X86 ML <x86@...nel.org>,
        "H. Peter Anvin" <hpa@...or.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Arnd Bergmann <arnd@...db.de>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Vlastimil Babka <vbabka@...e.cz>,
        Michal Hocko <mhocko@...nel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Linux ACPI <linux-acpi@...r.kernel.org>,
        linux-arch <linux-arch@...r.kernel.org>,
        Linux-MM <linux-mm@...ck.org>
Subject: Re: [RFC PATCH 0/7] mm: Get rid of vmalloc_sync_(un)mappings()

On Fri, May 08, 2020 at 02:33:19PM -0700, Andy Lutomirski wrote:
> On Fri, May 8, 2020 at 7:40 AM Joerg Roedel <joro@...tes.org> wrote:

> What's the maximum on other system types?  It might make more sense to
> take the memory hit and pre-populate all the tables at boot so we
> never have to sync them.

Need to look it up for 5-level paging, with 4-level paging its 64 pages
to pre-populate the vmalloc area.

But that would not solve the problem on x86-32, which needs to
synchronize unmappings on the PMD level.


	Joerg