Re: [tip:x86/mm] x86: Convert the rest of the code to support p4d_t

From	Dan Williams <dan.j.williams@intel.com>
Newsgroups	linux.kernel
Subject	Re: [tip:x86/mm] x86: Convert the rest of the code to support p4d_t
Date	2017-04-24 20:50 +0200
Message-ID	<tzRdD-29v-13@gated-at.bofh.it> (permalink)
References	<tm5gu-2nQ-37@gated-at.bofh.it> <tpAe7-6F9-23@gated-at.bofh.it> <tzvPQ-4qm-5@gated-at.bofh.it> <tzPvc-118-19@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On Mon, Apr 24, 2017 at 9:57 AM, Kirill A. Shutemov
<kirill@shutemov.name> wrote:
> On Sun, Apr 23, 2017 at 12:56:14PM -0700, Dan Williams wrote:
>> On Mon, Mar 27, 2017 at 3:25 AM, tip-bot for Kirill A. Shutemov
>> <tipbot@zytor.com> wrote:
>> > Commit-ID:  f2a6a7050109e0a5c7a84c70aa6010f682b2f1ee
>> > Gitweb:     http://git.kernel.org/tip/f2a6a7050109e0a5c7a84c70aa6010f682b2f1ee
>> > Author:     Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
>> > AuthorDate: Fri, 17 Mar 2017 21:55:15 +0300
>> > Committer:  Ingo Molnar <mingo@kernel.org>
>> > CommitDate: Mon, 27 Mar 2017 08:56:58 +0200
>> >
>> > x86: Convert the rest of the code to support p4d_t
>> >
>> > This patch converts x86 to use proper folding of a new (fifth) page table level
>> > with <asm-generic/pgtable-nop4d.h>.
>> >
>> > That's a bit of a kitchen sink patch, but I don't see how to split it further
>> > without hurting bisectability.
>> >
>> > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
>> > Acked-by: Thomas Gleixner <tglx@linutronix.de>
>> > Cc: Andrew Morton <akpm@linux-foundation.org>
>> > Cc: Andy Lutomirski <luto@amacapital.net>
>> > Cc: Andy Lutomirski <luto@kernel.org>
>> > Cc: Arnd Bergmann <arnd@arndb.de>
>> > Cc: Borislav Petkov <bp@alien8.de>
>> > Cc: Brian Gerst <brgerst@gmail.com>
>> > Cc: Dave Hansen <dave.hansen@intel.com>
>> > Cc: Denys Vlasenko <dvlasenk@redhat.com>
>> > Cc: H. Peter Anvin <hpa@zytor.com>
>> > Cc: Josh Poimboeuf <jpoimboe@redhat.com>
>> > Cc: Linus Torvalds <torvalds@linux-foundation.org>
>> > Cc: Michal Hocko <mhocko@suse.com>
>> > Cc: Peter Zijlstra <peterz@infradead.org>
>> > Cc: linux-arch@vger.kernel.org
>> > Cc: linux-mm@kvack.org
>> > Link: http://lkml.kernel.org/r/20170317185515.8636-7-kirill.shutemov@linux.intel.com
>> > Signed-off-by: Ingo Molnar <mingo@kernel.org>
>>
>> Following Ingo's revert of commit 2947ba054a4d "x86/mm/gup: Switch GUP
>> to the generic get_user_page_fast() implementation", I gave
>> tip.git/master a try to see if it resolved the original failing
>> signature I was seeing with the "device-dax" regression test [1] on
>> next/master. It turns out that there are two failing signatures and I
>> need to use the revert during the bisect to find this other
>> regression. This new bisect points to commit f2a6a7050109 "x86:
>> Convert the rest of the code to support p4d_t" as the culprit.
>>
>> [   43.194330] BUG: unable to handle kernel paging request at ffff880300000000
>
> I cannot reproduce the issue.
>
> Could you share your kernel kernel config?

Kernel config available here:
https://gist.github.com/djbw/2b99a014396cca9f4406586573be98c0

Thread

Re: [tip:x86/mm] x86: Convert the rest of the code to support p4d_t Dan Williams <dan.j.williams@intel.com> - 2017-04-23 22:00 +0200
  Re: [tip:x86/mm] x86: Convert the rest of the code to support p4d_t "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-04-24 19:00 +0200
    Re: [tip:x86/mm] x86: Convert the rest of the code to support p4d_t Dan Williams <dan.j.williams@intel.com> - 2017-04-24 20:50 +0200
      Re: [tip:x86/mm] x86: Convert the rest of the code to support p4d_t "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-04-25 03:10 +0200
        Re: [tip:x86/mm] x86: Convert the rest of the code to support p4d_t Ingo Molnar <mingo@kernel.org> - 2017-04-25 08:40 +0200
          Re: [tip:x86/mm] x86: Convert the rest of the code to support p4d_t "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-04-25 11:10 +0200

csiph-web