From: "Américo Wang" <xiyou.wangcong@gmail.com>
To: Pintu Agarwal <pintu_agarwal@yahoo.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Eric Dumazet <eric.dumazet@gmail.com>,
Changli Gao <xiaosuo@gmail.com>, Jiri Slaby <jslaby@suse.cz>,
azurIt <azurit@pobox.sk>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, Jiri Slaby <jirislaby@gmail.com>
Subject: Re: Regarding memory fragmentation using malloc....
Date: Wed, 13 Apr 2011 19:44:39 +0800 [thread overview]
Message-ID: <BANLkTi=7KHMA_JOwQcMQj5M+XU=qO07s2g@mail.gmail.com> (raw)
In-Reply-To: <530486.50523.qm@web162020.mail.bf1.yahoo.com>
On Wed, Apr 13, 2011 at 2:54 PM, Pintu Agarwal <pintu_agarwal@yahoo.com> wrote:
> Dear All,
>
> I am trying to understand how memory fragmentation occurs in linux using many malloc calls.
> I am trying to reproduce the page fragmentation problem in linux 2.6.29.x on a linux mobile(without Swap) using a small malloc(in loop) test program of BLOCK_SIZE (64*(4*K)).
> And then monitoring the page changes in /proc/buddyinfo after each operation.
> From the output I can see that the page values under buddyinfo keeps changing. But I am not able to relate these changes with my malloc BLOCK_SIZE.
> I mean with my BLOCK_SIZE of (2^6 x 4K ==> 2^6 PAGES) the 2^6 th block under /proc/buddyinfo should change. But this is not the actual behaviour.
> Whatever is the blocksize, the buddyinfo changes only for 2^0 or 2^1 or 2^2 or 2^3.
>
> I am trying to measure the level of fragmentation after each page allocation.
> Can somebody explain me in detail, how actually /proc/buddyinfo changes after each allocation and deallocation.
>
What malloc() sees is virtual memory of the process, while buddyinfo
shows physical memory pages.
When you malloc() 64K memory, the kernel may not allocate a 64K
physical memory at one time
for you.
Thanks.
next prev parent reply other threads:[~2011-04-13 11:44 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-15 13:25 Regression from 2.6.36 azurIt
2011-03-17 0:15 ` Greg KH
2011-03-17 0:53 ` Dave Jones
2011-03-17 13:30 ` azurIt
2011-04-07 10:01 ` azurIt
2011-04-07 10:19 ` Jiri Slaby
2011-04-07 11:21 ` Américo Wang
2011-04-07 11:57 ` Eric Dumazet
2011-04-07 12:13 ` Eric Dumazet
2011-04-07 15:27 ` Changli Gao
2011-04-07 15:36 ` Eric Dumazet
2011-04-12 22:49 ` Andrew Morton
2011-04-13 1:23 ` Changli Gao
2011-04-13 1:31 ` Andrew Morton
2011-04-13 2:37 ` Eric Dumazet
2011-04-13 6:54 ` Regarding memory fragmentation using malloc Pintu Agarwal
2011-04-13 11:44 ` Américo Wang [this message]
2011-04-13 13:56 ` Pintu Agarwal
2011-04-13 15:25 ` Michal Nazarewicz
2011-04-14 6:44 ` Pintu Agarwal
2011-04-14 10:47 ` Michal Nazarewicz
2011-04-14 12:24 ` Pintu Agarwal
2011-04-14 12:31 ` Michal Nazarewicz
2011-04-13 21:16 ` Regression from 2.6.36 Andrew Morton
2011-04-13 21:24 ` Andrew Morton
2011-04-19 19:29 ` azurIt
2011-04-19 19:55 ` Andrew Morton
2011-04-13 21:44 ` David Rientjes
2011-04-13 21:54 ` Andrew Morton
2011-04-14 2:10 ` Eric Dumazet
2011-04-14 5:28 ` Andrew Morton
2011-04-14 6:31 ` Eric Dumazet
2011-04-14 9:08 ` azurIt
2011-04-14 10:27 ` Eric Dumazet
2011-04-14 10:31 ` azurIt
2011-04-14 10:25 ` Mel Gorman
2011-04-15 9:59 ` azurIt
2011-04-15 10:47 ` Mel Gorman
2011-04-15 10:56 ` azurIt
2011-04-15 11:17 ` Mel Gorman
2011-04-15 11:36 ` azurIt
2011-04-15 13:01 ` Mel Gorman
2011-04-15 13:21 ` azurIt
2011-04-15 14:15 ` Mel Gorman
2011-04-08 12:25 ` azurIt
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