From: Balbir Singh <bsingharora@gmail.com>
To: Laurent Dufour <ldufour@linux.vnet.ibm.com>,
paulmck@linux.vnet.ibm.com, peterz@infradead.org,
akpm@linux-foundation.org, kirill@shutemov.name,
ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net,
jack@suse.cz, Matthew Wilcox <willy@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com,
npiggin@gmail.com, Tim Chen <tim.c.chen@linux.intel.com>
Subject: Re: [RFC v5 01/11] mm: Dont assume page-table invariance during faults
Date: Fri, 07 Jul 2017 17:07:02 +1000 [thread overview]
Message-ID: <1499411222.23251.5.camel@gmail.com> (raw)
In-Reply-To: <1497635555-25679-2-git-send-email-ldufour@linux.vnet.ibm.com>
On Fri, 2017-06-16 at 19:52 +0200, Laurent Dufour wrote:
> From: Peter Zijlstra <peterz@infradead.org>
>
> One of the side effects of speculating on faults (without holding
> mmap_sem) is that we can race with free_pgtables() and therefore we
> cannot assume the page-tables will stick around.
>
> Remove the relyance on the pte pointer.
^^ reliance
Looking at the changelog and the code the impact is not clear.
It looks like after this patch we always assume the pte is not
the same. What is the impact of this patch?
Balbir Singh.
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next prev parent reply other threads:[~2017-07-07 7:08 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-16 17:52 [RFC v5 00/11] Speculative page faults Laurent Dufour
2017-06-16 17:52 ` [RFC v5 01/11] mm: Dont assume page-table invariance during faults Laurent Dufour
2017-07-07 7:07 ` Balbir Singh [this message]
2017-07-10 17:48 ` Laurent Dufour
2017-07-11 4:26 ` Balbir Singh
2017-08-08 10:04 ` Anshuman Khandual
2017-08-08 9:45 ` Anshuman Khandual
2017-08-08 12:11 ` Laurent Dufour
2017-06-16 17:52 ` [RFC v5 02/11] mm: Prepare for FAULT_FLAG_SPECULATIVE Laurent Dufour
2017-08-08 10:24 ` Anshuman Khandual
2017-08-08 10:42 ` Peter Zijlstra
2017-06-16 17:52 ` [RFC v5 03/11] mm: Introduce pte_spinlock " Laurent Dufour
2017-08-08 10:35 ` Anshuman Khandual
2017-08-08 12:16 ` Laurent Dufour
2017-06-16 17:52 ` [RFC v5 04/11] mm: VMA sequence count Laurent Dufour
2017-08-08 10:59 ` Anshuman Khandual
2017-08-08 11:04 ` Peter Zijlstra
2017-06-16 17:52 ` [RFC v5 05/11] mm: fix lock dependency against mapping->i_mmap_rwsem Laurent Dufour
2017-08-08 11:17 ` Anshuman Khandual
2017-08-08 12:20 ` Laurent Dufour
2017-08-08 12:49 ` Jan Kara
2017-08-08 13:08 ` Laurent Dufour
2017-08-08 13:15 ` Peter Zijlstra
2017-08-08 13:34 ` Laurent Dufour
2017-06-16 17:52 ` [RFC v5 06/11] mm: Protect VMA modifications using VMA sequence count Laurent Dufour
2017-06-16 17:52 ` [RFC v5 07/11] mm: RCU free VMAs Laurent Dufour
2017-06-16 17:52 ` [RFC v5 08/11] mm: Provide speculative fault infrastructure Laurent Dufour
2017-06-16 17:52 ` [RFC v5 09/11] mm: Try spin lock in speculative path Laurent Dufour
2017-07-05 18:50 ` Peter Zijlstra
2017-07-06 13:46 ` Laurent Dufour
2017-07-06 14:48 ` Peter Zijlstra
2017-07-06 15:29 ` Laurent Dufour
2017-07-06 16:13 ` Peter Zijlstra
2017-06-16 17:52 ` [RFC v5 10/11] x86/mm: Add speculative pagefault handling Laurent Dufour
2017-06-16 17:52 ` [RFC v5 11/11] powerpc/mm: Add speculative page fault Laurent Dufour
2017-07-03 17:32 ` [RFC v5 00/11] Speculative page faults Laurent Dufour
2017-07-07 1:54 ` Balbir Singh
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