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
?
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.
?
Question:?
?1) Is there any way by which I can instruct my RH3.0 system?not to map the huge locale-archive file by default? Rather it should map the few small set of locale files, as mapped in RH7.2 system.
?2) If the answer of my previous question is yes (it is possible), then what will be the impact of doing that?
?
You can find the sample "sleep" commands below.
?
Thanks,
Arijit
?
RH3.0 on AMD64:
=============
vgamd126:arijit>sleep 400 &????????????????????????????????????????????????????????????????????????????????????
[1] 19916
vgamd126:arijit>pmap 19916
?Size (KB)??? Perm??? Associated files (if any)???????????????????
==========??? ====??? =============================================
??????? 16??? r-xp??? /bin/sleep
???????? 4??? rw-p??? /bin/sleep
?????? 132??? rwxp???
????? 1108??? r-xp??? /lib64/ld-2.3.2.so
???????? 4??? rw-p??? /lib64/ld-2.3.2.so
???????? 4??? rw-p???
?????? 540??? r-xp??? /lib64/tls/libm-2.3.2.so
????? 1024??? ---p??? /lib64/tls/libm-2.3.2.so
???????? 4??? rw-p??? /lib64/tls/libm-2.3.2.so
???????? 4??? rw-p???
??????? 36??? r-xp??? /lib64/tls/librtkaio-2.3.2.so
????? 1024??? ---p??? /lib64/tls/librtkaio-2.3.2.so
???????? 4??? rw-p??? /lib64/tls/librtkaio-2.3.2.so
??????? 64??? rw-p???
????? 1260??? r-xp??? /lib64/tls/libc-2.3.2.so
????? 1024??? ---p??? /lib64/tls/libc-2.3.2.so
??????? 20??? rw-p??? /lib64/tls/libc-2.3.2.so
??????? 16??? rw-p???
??????? 60??? r-xp??? /lib64/tls/libpthread-0.60.so
????? 1024??? ---p??? /lib64/tls/libpthread-0.60.so
???????? 4??? rw-p??? /lib64/tls/libpthread-0.60.so
??????? 20??? rw-p???
???? 31396??? r--p??? /usr/lib/locale/locale-archive
??????? 24??? rw-p???
Total Virtual Memory = 38816 KB
vgamd126:arijit>
?
?
RH7.2 in i686
==========
eurika120:arijit>sleep 400 &???????????????????????????????????????????????????????????????????????????????????????????
[1] 11065
eurika120:arijit>pmap 11065
?Size (KB)??? Perm??? Associated files (if any)???????????????????
==========??? ====??? =============================================
??????? 12??? r-xp??? /bin/sleep
???????? 4??? rw-p??? /bin/sleep
???????? 8??? rwxp???
??????? 88??? r-xp??? /lib/ld-2.2.4.so
???????? 4??? rw-p??? /lib/ld-2.2.4.so
???????? 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
???????? 4??? rw-p???
?????? 136??? r-xp??? /lib/i686/libm-2.2.4.so
???????? 4??? rw-p??? /lib/i686/libm-2.2.4.so
??????? 28??? r-xp??? /lib/librt-2.2.4.so
???????? 4??? rw-p??? /lib/librt-2.2.4.so
??????? 40??? rw-p???
????? 1224??? r-xp??? /lib/i686/libc-2.2.4.so
??????? 20??? rw-p??? /lib/i686/libc-2.2.4.so
??????? 16??? rw-p???
??????? 52??? r-xp??? /lib/i686/libpthread-0.9.so
??????? 32??? rw-p??? /lib/i686/libpthread-0.9.so
?????? 172??? r--p??? /usr/lib/locale/en_US/LC_CTYPE
??????? 24??? rwxp???
Total Virtual Memory = 1936 KB
eurika120:arijit>
> 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.
There is no RH 3.0 for AMD64 - if you mean RHEL 3 then the mappings are
shared between processes.
On Fri, 30 Sep 2005, 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
> ?
> 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.
> ?
> Question:?
> ?1) Is there any way by which I can instruct my RH3.0 system?not to map the huge locale-archive file by default? Rather it should map the few small set of locale files, as mapped in RH7.2 system.
> ?2) If the answer of my previous question is yes (it is possible), then what will be the impact of doing that?
> ?
> You can find the sample "sleep" commands below.
> ?
> Thanks,
> Arijit
> ?
> RH3.0 on AMD64:
> =============
> vgamd126:arijit>sleep 400 &????????????????????????????????????????????????????????????????????????????????????
> [1] 19916
> vgamd126:arijit>pmap 19916
> ?Size (KB)??? Perm??? Associated files (if any)???????????????????
> ==========??? ====??? =============================================
> ??????? 16??? r-xp??? /bin/sleep
> ???????? 4??? rw-p??? /bin/sleep
> ?????? 132??? rwxp???
> ????? 1108??? r-xp??? /lib64/ld-2.3.2.so
> ???????? 4??? rw-p??? /lib64/ld-2.3.2.so
> ???????? 4??? rw-p???
> ?????? 540??? r-xp??? /lib64/tls/libm-2.3.2.so
> ????? 1024??? ---p??? /lib64/tls/libm-2.3.2.so
> ???????? 4??? rw-p??? /lib64/tls/libm-2.3.2.so
> ???????? 4??? rw-p???
> ??????? 36??? r-xp??? /lib64/tls/librtkaio-2.3.2.so
> ????? 1024??? ---p??? /lib64/tls/librtkaio-2.3.2.so
> ???????? 4??? rw-p??? /lib64/tls/librtkaio-2.3.2.so
> ??????? 64??? rw-p???
> ????? 1260??? r-xp??? /lib64/tls/libc-2.3.2.so
> ????? 1024??? ---p??? /lib64/tls/libc-2.3.2.so
> ??????? 20??? rw-p??? /lib64/tls/libc-2.3.2.so
> ??????? 16??? rw-p???
> ??????? 60??? r-xp??? /lib64/tls/libpthread-0.60.so
> ????? 1024??? ---p??? /lib64/tls/libpthread-0.60.so
> ???????? 4??? rw-p??? /lib64/tls/libpthread-0.60.so
> ??????? 20??? rw-p???
> ???? 31396??? r--p??? /usr/lib/locale/locale-archive
> ??????? 24??? rw-p???
> Total Virtual Memory = 38816 KB
> vgamd126:arijit>
> ?
> ?
> RH7.2 in i686
> ==========
> eurika120:arijit>sleep 400 &???????????????????????????????????????????????????????????????????????????????????????????
> [1] 11065
> eurika120:arijit>pmap 11065
> ?Size (KB)??? Perm??? Associated files (if any)???????????????????
> ==========??? ====??? =============================================
> ??????? 12??? r-xp??? /bin/sleep
> ???????? 4??? rw-p??? /bin/sleep
> ???????? 8??? rwxp???
> ??????? 88??? r-xp??? /lib/ld-2.2.4.so
> ???????? 4??? rw-p??? /lib/ld-2.2.4.so
> ???????? 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
> ???????? 4??? rw-p???
> ?????? 136??? r-xp??? /lib/i686/libm-2.2.4.so
> ???????? 4??? rw-p??? /lib/i686/libm-2.2.4.so
> ??????? 28??? r-xp??? /lib/librt-2.2.4.so
> ???????? 4??? rw-p??? /lib/librt-2.2.4.so
> ??????? 40??? rw-p???
> ????? 1224??? r-xp??? /lib/i686/libc-2.2.4.so
> ??????? 20??? rw-p??? /lib/i686/libc-2.2.4.so
> ??????? 16??? rw-p???
> ??????? 52??? r-xp??? /lib/i686/libpthread-0.9.so
> ??????? 32??? rw-p??? /lib/i686/libpthread-0.9.so
> ?????? 172??? r--p??? /usr/lib/locale/en_US/LC_CTYPE
> ??????? 24??? rwxp???
> Total Virtual Memory = 1936 KB
> eurika120:arijit>
>
Those private mappings are much smaller than the whole shared
libraries. They are probably gap-fillers because the libraries
don't end on page boundaries and mapping is per-page. The
gap-fillers shown as "---p" will have PROT_NONE attributes
and therefore can't be read/written/exec, etc. In other words,
it's perfectly normal and you wouldn't want to do anything about it.
Cheers,
Dick Johnson
Penguin : Linux version 2.6.13 on an i686 machine (5589.55 BogoMips).
Warning : 98.36% of all statistics are fiction.
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Thank you.
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
Shared mappings are represented in /proc/<pid>/maps file as having 's'
as its last permission field like r-xs (shared readable and executable
region)
But in this case, the perm bits are r--p which says that it is private
rather than shared. Any idea whatz happening here...?
-Arijit
-----Original Message-----
From: Alan Cox [mailto:[email protected]]
Sent: Friday, September 30, 2005 7:13 PM
To: Arijit Das
Cc: [email protected]
Subject: Re: RH30: Virtual Mem shot heavily by locale-archive...
> 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.
There is no RH 3.0 for AMD64 - if you mean RHEL 3 then the mappings are
shared between processes.
On Sat, 2005-10-01 at 14:49 +0530, Arijit Das wrote:
> Shared mappings are represented in /proc/<pid>/maps file as having 's'
> as its last permission field like r-xs (shared readable and executable
> region)
>
> But in this case, the perm bits are r--p which says that it is private
> rather than shared. Any idea whatz happening here...?
what is the problem??????
private mappings don't take up "extra" memory *unless you write to them*
due to copy-on-write behavior of the kernel. r--p means you can't
write.... so what's the problem..