From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>, Ingo Molnar <mingo@redhat.com>,
Paul Mackerras <paulus@samba.org>, Mel Gorman <mgorman@suse.de>,
Sasha Levin <sasha.levin@oracle.com>,
Dave Jones <davej@redhat.com>,
LinuxPPC-dev <linuxppc-dev@lists.ozlabs.org>,
Kirill Shutemov <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa
Date: Wed, 03 Dec 2014 07:13:10 +1100 [thread overview]
Message-ID: <1417551190.27448.8.camel@kernel.crashing.org> (raw)
In-Reply-To: <87h9xeh5im.fsf@linux.vnet.ibm.com>
On Tue, 2014-12-02 at 13:01 +0530, Aneesh Kumar K.V wrote:
> Benjamin Herrenschmidt <benh@kernel.crashing.org> writes:
>
> > On Fri, 2014-11-21 at 13:57 +0000, Mel Gorman wrote:
> >> void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep,
> >> pte_t pte)
> >> {
> >> -#ifdef CONFIG_DEBUG_VM
> >> - WARN_ON(pte_val(*ptep) & _PAGE_PRESENT);
> >> -#endif
> >> + /*
> >> + * When handling numa faults, we already have the pte marked
> >> + * _PAGE_PRESENT, but we can be sure that it is not in hpte.
> >> + * Hence we can use set_pte_at for them.
> >> + */
> >> + VM_WARN_ON((pte_val(*ptep) & (_PAGE_PRESENT | _PAGE_USER)) ==
> >> + (_PAGE_PRESENT | _PAGE_USER));
> >> +
> >
> > His is that going to fare with set_pte_at() called for kernel pages ?
> >
>
> Yes, we won't capture those errors now. But is there any other debug
> check i could use to capture the wrong usage of set_pte_at ?
Actually the above is fine, for some reason I mis-read the test as
blowing on kernel pages, it doesn't.
We probably do need to make sure however that protnone isn't used for
kernel pages.
Cheers,
Ben.
> -aneesh
>
> --
> To unsubscribe, send a message with 'unsubscribe linux-mm' in
> the body to majordomo@kvack.org. For more info on Linux MM,
> see: http://www.linux-mm.org/ .
> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2014-12-02 20:13 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-21 13:57 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v3 Mel Gorman
2014-11-21 13:57 ` [PATCH 01/10] mm: numa: Do not dereference pmd outside of the lock during NUMA hinting fault Mel Gorman
2014-11-21 13:57 ` [PATCH 02/10] mm: Add p[te|md] protnone helpers for use by NUMA balancing Mel Gorman
2014-12-01 22:38 ` Benjamin Herrenschmidt
2014-12-02 10:12 ` Mel Gorman
2014-11-21 13:57 ` [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa Mel Gorman
2014-12-01 22:42 ` Benjamin Herrenschmidt
2014-12-02 7:27 ` Aneesh Kumar K.V
2014-12-02 20:11 ` Benjamin Herrenschmidt
2014-12-03 15:23 ` Aneesh Kumar K.V
2014-12-03 15:52 ` Mel Gorman
2014-12-03 17:20 ` Aneesh Kumar K.V
2014-12-04 11:17 ` Mel Gorman
2014-12-03 21:01 ` Benjamin Herrenschmidt
2014-12-04 11:15 ` Mel Gorman
2014-12-01 22:44 ` Benjamin Herrenschmidt
2014-12-02 7:31 ` Aneesh Kumar K.V
2014-12-02 20:13 ` Benjamin Herrenschmidt [this message]
2014-11-21 13:57 ` [PATCH 04/10] ppc64: Add paranoid warnings for unexpected DSISR_PROTFAULT Mel Gorman
2014-11-21 13:57 ` [PATCH 05/10] mm: Convert p[te|md]_mknonnuma and remaining page table manipulations Mel Gorman
2014-11-21 13:57 ` [PATCH 06/10] mm: Remove remaining references to NUMA hinting bits and helpers Mel Gorman
2014-11-21 13:57 ` [PATCH 07/10] mm: numa: Do not trap faults on the huge zero page Mel Gorman
2014-11-21 13:57 ` [PATCH 08/10] x86: mm: Restore original pte_special check Mel Gorman
2014-11-21 13:57 ` [PATCH 09/10] mm: numa: Add paranoid check around pte_protnone_numa Mel Gorman
2014-11-21 13:57 ` [PATCH 10/10] mm: numa: Avoid unnecessary TLB flushes when setting NUMA hinting entries Mel Gorman
-- strict thread matches above, loose matches on Subject: below --
2015-01-05 10:54 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v5 Mel Gorman
2015-01-05 10:54 ` [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa Mel Gorman
2014-12-04 11:24 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v4 Mel Gorman
2014-12-04 11:24 ` [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa Mel Gorman
2014-11-20 10:19 [PATCH 0/10] Replace _PAGE_NUMA with PAGE_NONE protections v2 Mel Gorman
2014-11-20 10:19 ` [PATCH 03/10] mm: Convert p[te|md]_numa users to p[te|md]_protnone_numa Mel Gorman
2014-11-20 10:38 ` David Laight
2014-11-20 10:47 ` Mel Gorman
2014-11-21 5:28 ` Aneesh Kumar K.V
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1417551190.27448.8.camel@kernel.crashing.org \
--to=benh@kernel.crashing.org \
--cc=aneesh.kumar@linux.vnet.ibm.com \
--cc=davej@redhat.com \
--cc=hughd@google.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=paulus@samba.org \
--cc=riel@redhat.com \
--cc=sasha.levin@oracle.com \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).