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From: Hugh Dickins <hugh@veritas.com>
To: sameer sameer <sameerchakravarthy@yahoo.com>
Cc: linux-mm@kvack.org
Subject: Re: question on mmap
Date: Fri, 13 Apr 2007 18:59:30 +0100 (BST)	[thread overview]
Message-ID: <Pine.LNX.4.64.0704131856050.8823@blonde.wat.veritas.com> (raw)
In-Reply-To: <835465.82854.qm@web43140.mail.sp1.yahoo.com>

On Wed, 11 Apr 2007, sameer sameer wrote:
> 
> I have a question regarding the implementation of
> mmap. I am trying to find out if we the kernel
> actually shares the memory across unrelated processes
> using MAP_SHARED flag for a read only file mapping. 

Yes, it does.

> 
> When the file is mapped with PROT_READ arguement, then
> will there be any difference in memory usage by
> multiple processes if the mapping is done using
> MAP_SHARED instead of MAP_PRIVATE ?

No, no difference.

> 
> Are there any system commands which will let me know
> how to calcuate the memory savings (if there are any)

No such savings.

Hugh

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  reply	other threads:[~2007-04-13 17:59 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-04-10 19:19 [SLUB 1/5] Fix object counting Christoph Lameter
2007-04-10 19:19 ` [SLUB 2/5] Enable tracking of full slabs Christoph Lameter
2007-04-10 19:19 ` [SLUB 3/5] Validation of slabs (metadata and guard zones) Christoph Lameter
2007-04-10 20:31   ` Andrew Morton
2007-04-10 20:47     ` Dave Jones
2007-04-10 21:42       ` Andrew Morton
2007-04-10 21:10     ` Christoph Lameter
2007-04-10 21:13     ` Christoph Lameter
2007-04-10 21:14     ` Christoph Lameter
2007-04-10 21:15     ` Christoph Lameter
2007-04-10 21:21     ` Christoph Lameter
2007-04-10 21:40     ` Christoph Lameter
2007-04-10 22:49     ` Christoph Lameter
2007-04-10 23:43       ` Andrew Morton
2007-04-10 23:17     ` Christoph Lameter
2007-04-10 23:38     ` Christoph Lameter
2007-04-11  0:00     ` Christoph Lameter
2007-04-11  0:15     ` Christoph Lameter
2007-04-11  6:24       ` question on mmap sameer sameer
2007-04-13 17:59         ` Hugh Dickins [this message]
2007-04-11  2:24     ` [SLUB 3/5] Validation of slabs (metadata and guard zones) Christoph Lameter
2007-04-11  3:08       ` Andrew Morton
2007-04-10 19:19 ` [SLUB 4/5] Add ability to list alloc / free callers per slab Christoph Lameter
2007-04-10 19:19 ` [SLUB 5/5] Drop version number Christoph Lameter

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