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From: Michal Hocko <mhocko@kernel.org>
To: Florian Weimer <fweimer@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>,
	mtk.manpages@gmail.com, linux-man@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	Andrea Arcangeli <aarcange@redhat.com>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	Anshuman Khandual <khandual@linux.vnet.ibm.com>,
	linux-mm@kvack.org
Subject: Re: [patch] mremap.2: Add description of old_size == 0 functionality
Date: Mon, 25 Sep 2017 14:35:08 +0200	[thread overview]
Message-ID: <20170925123508.pzjbe7wgwagnr5li@dhcp22.suse.cz> (raw)
In-Reply-To: <a5d279cb-a015-f74c-2e40-a231aa7f7a8c@redhat.com>

On Tue 19-09-17 14:11:19, Florian Weimer wrote:
> On 09/18/2017 07:11 PM, Mike Kravetz wrote:
[...]
> > I can drop this wording, but would still like to suggest memfd_create as
> > the preferred method of creating duplicate mappings.  It would be good if
> > others on Cc: could comment as well.
> 
> mremap seems to work with non-anonymous mappings, too:

only for shared mappings in fact. Because once we have CoW then mremap
will not provide you with the same content as the original mapping.

[...]

> > Just curious, does glibc make use of this today?  Or, is this just something
> > that you think may be useful.
> 
> To my knowledge, we do not use this today.  But it certainly looks very
> useful.

What would be the usecase. I mean why don't you simply create a new
mapping by a plain mmap when you have no guarantee about the same
content?
-- 
Michal Hocko
SUSE Labs

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  parent reply	other threads:[~2017-09-25 12:35 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20170915213745.6821-1-mike.kravetz@oracle.com>
2017-09-15 21:53 ` Mike Kravetz
2017-09-18 13:45   ` Florian Weimer
2017-09-18 17:11     ` Mike Kravetz
2017-09-19 12:11       ` Florian Weimer
2017-09-19 21:42         ` [patch v2] " Mike Kravetz
2017-09-20  7:25           ` Michael Kerrisk (man-pages)
2017-09-25 12:36             ` Michal Hocko
2017-09-25 12:40               ` Michael Kerrisk (man-pages)
2017-09-25 16:33             ` Mike Kravetz
2017-09-25 19:26               ` Michael Kerrisk (man-pages)
2017-09-25 12:35         ` Michal Hocko [this message]
2017-09-25 12:40           ` [patch] " Florian Weimer
2017-09-25 12:52             ` Michal Hocko
2017-09-25 13:16               ` Florian Weimer
2017-09-25 14:52                 ` Michal Hocko
2017-09-25 14:54                   ` Florian Weimer
2017-09-18  1:52 ` Jann Horn
2017-09-18 17:19   ` Mike Kravetz

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