From: Anshuman Khandual <khandual@linux.vnet.ibm.com>
To: Mike Kravetz <mike.kravetz@oracle.com>,
linux-mm@kvack.org, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Michal Hocko <mhocko@suse.com>, Aaron Lu <aaron.lu@intel.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [RFC PATCH 0/1] mm/mremap: add MREMAP_MIRROR flag
Date: Fri, 7 Jul 2017 16:33:36 +0530 [thread overview]
Message-ID: <0f935c5a-2580-c95a-4ea5-c25e796dad03@linux.vnet.ibm.com> (raw)
In-Reply-To: <1499357846-7481-1-git-send-email-mike.kravetz@oracle.com>
On 07/06/2017 09:47 PM, Mike Kravetz wrote:
> The mremap system call has the ability to 'mirror' parts of an existing
> mapping. To do so, it creates a new mapping that maps the same pages as
> the original mapping, just at a different virtual address. This
> functionality has existed since at least the 2.6 kernel [1]. A comment
> was added to the code to help preserve this feature.
In mremap() implementation move_vma() attempts to do do_unmap() after
move_page_tables(). do_unmap() on the original VMA bails out because
the requested length being 0. Hence both the original VMA and the new
VMA remains after the page table migration. Seems like this whole
mirror function is by coincidence or it has been designed that way ?
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next prev parent reply other threads:[~2017-07-07 11:05 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-06 16:17 [RFC PATCH 0/1] mm/mremap: add MREMAP_MIRROR flag Mike Kravetz
2017-07-06 16:17 ` [RFC PATCH 1/1] mm/mremap: add MREMAP_MIRROR flag for existing mirroring functionality Mike Kravetz
2017-07-07 8:45 ` Anshuman Khandual
2017-07-07 17:14 ` Mike Kravetz
2017-07-09 7:23 ` Anshuman Khandual
2017-07-07 10:23 ` Kirill A. Shutemov
2017-07-07 17:29 ` Mike Kravetz
2017-07-07 17:45 ` Kirill A. Shutemov
2017-07-07 18:09 ` Mike Kravetz
2017-07-09 7:32 ` Anshuman Khandual
2017-07-10 16:22 ` Vlastimil Babka
2017-07-10 17:22 ` Mike Kravetz
2017-07-11 12:36 ` Michal Hocko
2017-07-11 18:23 ` Mike Kravetz
2017-07-11 21:02 ` Andrea Arcangeli
2017-07-11 21:57 ` Mike Kravetz
2017-07-11 23:31 ` Andrea Arcangeli
2017-07-12 11:46 ` Michal Hocko
2017-07-12 16:55 ` Mike Kravetz
2017-07-13 6:16 ` Michal Hocko
2017-07-13 16:01 ` Mike Kravetz
2017-07-13 16:30 ` Andrea Arcangeli
2017-07-13 18:11 ` Mike Kravetz
2017-07-13 20:33 ` Andrea Arcangeli
2017-07-07 8:19 ` [RFC PATCH 0/1] mm/mremap: add MREMAP_MIRROR flag Anshuman Khandual
2017-07-07 17:04 ` Mike Kravetz
2017-07-07 11:03 ` Anshuman Khandual [this message]
2017-07-07 17:12 ` Mike Kravetz
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