From: Brian Gerst <bgerst@didntduck.org>
To: Arijit Das <Arijit.Das@synopsys.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: RH30: Virtual Mem shot heavily by locale-archive...
Date: Fri, 30 Sep 2005 11:20:14 -0400 [thread overview]
Message-ID: <433D57AE.9080103@didntduck.org> (raw)
In-Reply-To: <7EC22963812B4F40AE780CF2F140AFE9168304@IN01WEMBX1.internal.synopsys.com>
Arijit Das wrote:
> I have RH3.0 installed in an AMD64 machine.
>
> In this system, when I look at the virtual address space mappings of a process (say a sleep process), I find that almost 80% of its virtual address space has been taken by a private copy of /usr/lib/locale/locale-archive mapped to its virtual address space by default. Check this:
>
> 31396 KB r--p /usr/lib/locale/locale-archive
>
Only the pages of the file that are actually accessed are loaded into
physical memory. This mapping just reserves a slot of virtual memory
for those demand loaded pages to be mapped.
> Total Virtual Memory = 38816 KB
> On the other hand, when I look at the same info in a RH7.2 system, I see that a few small set of essential locale files have been mapped whose overall summed up size is around 236KB (way smaller than RH3.0)...Check this:
> 4 r--p /usr/lib/locale/en_US/LC_IDENTIFICATION
> 4 r--p /usr/lib/locale/en_US/LC_MEASUREMENT
> 4 r--p /usr/lib/locale/en_US/LC_TELEPHONE
> 4 r--p /usr/lib/locale/en_US/LC_ADDRESS
> 4 r--p /usr/lib/locale/en_US/LC_NAME
> 4 r--p /usr/lib/locale/en_US/LC_PAPER
> 4 r--p /usr/lib/locale/en_US/LC_MESSAGES/SYS_LC_MESSAGES
> 4 r--p /usr/lib/locale/en_US/LC_MONETARY
> 24 r--p /usr/lib/locale/en_US/LC_COLLATE
> 4 r--p /usr/lib/locale/en_US/LC_TIME
> 4 r--p /usr/lib/locale/en_US/LC_NUMERIC
> 172 r--p /usr/lib/locale/en_US/LC_CTYPE
> This seems like a huge requirement of memory for each small process executed in the RH3.0 system and hence, shots up the memory requirement of the entire system because the mapped region /usr/lib/locale/locale-archive is privately mapped.
Private mapping means copy-on-write. But since these mappings are
read-only they will still be shared by other users of that file. So no
extra physical memory for each process mapping the file.
--
Brian Gerst
next prev parent reply other threads:[~2005-09-30 15:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-30 13:01 RH30: Virtual Mem shot heavily by locale-archive Arijit Das
2005-09-30 13:42 ` Alan Cox
2005-09-30 14:11 ` linux-os (Dick Johnson)
2005-09-30 15:20 ` Brian Gerst [this message]
-- strict thread matches above, loose matches on Subject: below --
2005-10-01 9:19 Arijit Das
2005-10-01 9:35 ` Arjan van de Ven
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