thr3ads.net - Xen users - [Xen-users] Why my system only use 3.3G memory ? [Jul 2005]

If this information is useful, please help other people find it:
Share via:

she11c0de she11c0de

2005-Jul-07 05:49 UTC

[Xen-users] Why my system only use 3.3G memory ?

Hi, all

I have a server used to install Xen-2.0.6 on CentOS 4.1 
i386, hardware is DELL 2850, dual Xeon 3.2G CPU, 6G memory, use myself 
custom compiled xen kernel(dom0 and domU), i know xen 2.0 on i386 only 
use 4G memory, but i found on my server, it''s only use 3327M memory,
whit''s
problem, who can help me?

Here is some info.

[root@CentOS4 ~]#  xm 
info
system                 
: 
Linux
host                   
: 
CentOS4
release                
: 
2.6.11.10-xen0
version                
: #3 Fri Jul 1 02:54:48 CST 
2005
machine                
: 
i686
cores                  
: 2
hyperthreads_per_core  : 
2
cpu_mhz                
: 
3192
memory                 
: 
3327
free_memory            
: 2913

[root@CentOS4 ~]#  xm dmesg | less
ERROR: cannot use 
unconfigured serial port COM1
 __  
__            
____    ___   __   
 \ \/ /___ _ 
__   |___ \  / _ \ / /_  
  \  // _ \ ''_ 
\    __) || | | | ''_ \ 
  /  \  __/ | | 
|  / __/ | |_| | (_) |
 /_/\_\___|_| |_| |_____(_)___(_)___/ 

 http://www.cl.cam.ac.uk/netos/xen
 University 
of Cambridge Computer Laboratory

 Xen version 2.0.6 (tongjian@(none)) (gcc version 3.4.3 
20050227 (Red Hat 3.4.3-22.1)) Fri Jul  1 02:53:42 CST 
2005
 Latest ChangeSet: information unavailable

(XEN) WARNING: Only the first 4GB of the physical memory map can be 
accessed
(XEN)          by 
Xen in 32-bit mode. Truncating the memory map...
(XEN) Physical RAM 
map:
(XEN)  0000000000000000 - 00000000000a0000 
(usable)
(XEN)  0000000000100000 - 00000000cffc0000 
(usable)
(XEN)  00000000cffc0000 - 00000000cffcfc00 (ACPI 
data)
(XEN)  00000000cffcfc00 - 00000000cffff000 
(reserved)
(XEN)  00000000e0000000 - 00000000fec90000 
(reserved)
(XEN)  00000000fed00000 - 00000000fed00400 
(reserved)
(XEN)  00000000fee00000 - 00000000fee10000 
(reserved)
(XEN)  00000000ffb00000 - 0000000100000000 
(reserved)
(XEN) System RAM: 3327MB (3407232kB)
(XEN) Xen heap: 10MB 
(10680kB)
(XEN) CPU0: Before vendor init, caps: bfebfbff 20100000 
00000000, vendor = 0
(XEN) CPU#0: Physical ID: 0, Logical ID: 0
(XEN) 
CPU caps: bfebfbff 20100000 00000000 00000000
(XEN) found SMP MP-table 
at 000fe710
(XEN) ACPI: RSDP (v000 
DELL                                      
) @ 0x000fd650
(XEN) ACPI: RSDT (v001 DELL   PE 
BKC   0x00000001 MSFT 0x0100000a) @ 0x000fd664
(XEN) ACPI: 
FADT (v001 DELL   PE BKC   0x00000001 MSFT 0x0100000a) 
@ 0x000fd6b0
(XEN) ACPI: MADT (v001 DELL   PE BKC   
0x00000001 MSFT 0x0100000a) @ 0x000fd724
(XEN) ACPI: SPCR (v001 
DELL   PE BKC   0x00000001 MSFT 0x0100000a) @ 
0x000fd7cc
(XEN) ACPI: HPET (v001 DELL   PE BKC   
0x00000001 MSFT 0x0100000a) @ 0x000fd81c
(XEN) ACPI: MCFG (v001 
DELL   PE BKC   0x00000001 MSFT 0x0100000a) @ 
0x000fd854
(XEN) ACPI: DSDT (v001 DELL   PE BKC   
0x00000001 MSFT 0x0100000e) @ 0x00000000
(XEN) ACPI: Local APIC address 
0xfee00000
(XEN) ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] 
enabled)
(XEN) Processor #0 Unknown CPU [15:4] APIC version 20
(XEN) 
ACPI: LAPIC (acpi_id[0x02] lapic_id[0x06] enabled)
(XEN) Processor #6 
Unknown CPU [15:4] APIC version 20
(XEN) ACPI: LAPIC (acpi_id[0x03] 
lapic_id[0x01] enabled)
(XEN) Processor #1 Unknown CPU [15:4] APIC 
version 20
[root@CentOS4 ~]# 

使用 MSN 
Messenger 与联机的朋友进行交流

--===============1028264130=Content-Type: text/plain;
charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users
--===============1028264130==--

Tongjian

2005-Jul-07 07:17 UTC

head link

[Xen-users] Why my system only use 3.3G memory ?

Hi, all

I have a server used to install Xen-2.0.6 on CentOS 4.1 i386, hardware
is DELL 2850, dual Xeon 3.2G CPU, 6G memory, use myself custom
compiled xen kernel(dom0 and domU), i know xen 2.0 on i386 only use 4G
memory, but i found on my server, it''s only use 3327M memory,
whit''s
problem, who can help me?

Here is some info.

[root@CentOS4 ~]#  xm info
system                 : Linux
host                   : CentOS4
release                : 2.6.11.10-xen0
version                : #3 Fri Jul 1 02:54:48 CST 2005
machine                : i686
cores                  : 2
hyperthreads_per_core  : 2
cpu_mhz                : 3192
memory                 : 3327
free_memory            : 2913


[root@CentOS4 ~]#  xm dmesg | less
ERROR: cannot use unconfigured serial port COM1
 __  __            ____    ___   __  
 \ \/ /___ _ __   |___ \  / _ \ / /_ 
  \  // _ \ ''_ \    __) || | | | ''_ \
  /  \  __/ | | |  / __/ | |_| | (_) |
 /_/\_\___|_| |_| |_____(_)___(_)___/
                                     
 http://www.cl.cam.ac.uk/netos/xen
 University of Cambridge Computer Laboratory

 Xen version 2.0.6 (tongjian@(none <mailto:tongjian@%28none>)) (gcc
version 3.4.3 20050227 (Red Hat 3.4.3-22.1)) Fri Jul  1 02:53:42 CST 2005
 Latest ChangeSet: information unavailable

(XEN) WARNING: Only the first 4GB of the physical memory map can be accessed
(XEN)          by Xen in 32-bit mode. Truncating the memory map...
(XEN) Physical RAM map:
(XEN)  0000000000000000 - 00000000000a0000 (usable)
(XEN)  0000000000100000 - 00000000cffc0000 (usable)
(XEN)  00000000cffc0000 - 00000000cffcfc00 (ACPI data)
(XEN)  00000000cffcfc00 - 00000000cffff000 (reserved)
(XEN)  00000000e0000000 - 00000000fec90000 (reserved)
(XEN)  00000000fed00000 - 00000000fed00400 (reserved)
(XEN)  00000000fee00000 - 00000000fee10000 (reserved)
(XEN)  00000000ffb00000 - 0000000100000000 (reserved)
(XEN) System RAM: 3327MB (3407232kB)
(XEN) Xen heap: 10MB (10680kB)
(XEN) CPU0: Before vendor init, caps: bfebfbff 20100000 00000000, vendor = 0
(XEN) CPU#0: Physical ID: 0, Logical ID: 0
(XEN) CPU caps: bfebfbff 20100000 00000000 00000000
(XEN) found SMP MP-table at 000fe710
(XEN) ACPI: RSDP (v000 DELL                                      ) @
0x000fd650
(XEN) ACPI: RSDT (v001 DELL   PE BKC   0x00000001 MSFT 0x0100000a) @
0x000fd664
(XEN) ACPI: FADT (v001 DELL   PE BKC   0x00000001 MSFT 0x0100000a) @
0x000fd6b0
(XEN) ACPI: MADT (v001 DELL   PE BKC   0x00000001 MSFT 0x0100000a) @
0x000fd724
(XEN) ACPI: SPCR (v001 DELL   PE BKC   0x00000001 MSFT 0x0100000a) @
0x000fd7cc
(XEN) ACPI: HPET (v001 DELL   PE BKC   0x00000001 MSFT 0x0100000a) @
0x000fd81c
(XEN) ACPI: MCFG (v001 DELL   PE BKC   0x00000001 MSFT 0x0100000a) @
0x000fd854
(XEN) ACPI: DSDT (v001 DELL   PE BKC   0x00000001 MSFT 0x0100000e) @
0x00000000
(XEN) ACPI: Local APIC address 0xfee00000
(XEN) ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled)
(XEN) Processor #0 Unknown CPU [15:4] APIC version 20
(XEN) ACPI: LAPIC (acpi_id[0x02] lapic_id[0x06] enabled)
(XEN) Processor #6 Unknown CPU [15:4] APIC version 20
(XEN) ACPI: LAPIC (acpi_id[0x03] lapic_id[0x01] enabled)
(XEN) Processor #1 Unknown CPU [15:4] APIC version 20
[root@CentOS4 ~]#

-- 


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Ian Pratt

2005-Jul-07 08:05 UTC

head link

RE: [Xen-users] Why my system only use 3.3G memory ?

(XEN) Physical RAM map:
(XEN)  0000000000000000 - 00000000000a0000 (usable)
(XEN)  0000000000100000 - 00000000cffc0000 (usable)
(XEN)  00000000cffc0000 - 00000000cffcfc00 (ACPI data)
(XEN)  00000000cffcfc00 - 00000000cffff000 (reserved)
(XEN)  00000000e0000000 - 00000000fec90000 (reserved)
(XEN)  00000000fed00000 - 00000000fed00400 (reserved)
(XEN)  00000000fee00000 - 00000000fee10000 (reserved)
(XEN)  00000000ffb00000 - 0000000100000000 (reserved)
(XEN) System RAM: 3327MB (3407232kB)

Your BIOS has created a whole at the top of the memory map into which the memory
mapped PCI devices have been placed, effectively hiding the memory from use.

What is slightly odd is that the whole is larger than I've seen before. I
presume its the area between cffff000 and e0000000 which isn't listed in the
e820 map (everything above cffc0000 is unusable).

You'll have to wait until xen3 and use x86_32pae or x86_64 to use more
memory.

Ian
> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com 
> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of 
> she11c0de she11c0de
> Sent: 07 July 2005 06:50
> To: xen-users@lists.xensource.com
> Subject: [Xen-users] Why my system only use 3.3G memory ?
> 
> Hi, all
> 
> I have a server used to install Xen-2.0.6 on CentOS 4.1 i386, 
> hardware is DELL 2850, dual Xeon 3.2G CPU, 6G memory, use 
> myself custom compiled xen kernel(dom0 and domU), i know xen 
> 2.0 on i386 only use 4G memory, but i found on my server, 
> it's only use 3327M memory, whit's problem, who can help me?
> 
> Here is some info.
> 
> [root@CentOS4 ~]#  xm info
> system                 : Linux
> host                   : CentOS4
> release                : 2.6.11.10-xen0
> version                : #3 Fri Jul 1 02:54:48 CST 2005
> machine                : i686
> cores                  : 2
> hyperthreads_per_core  : 2
> cpu_mhz                : 3192
> memory                 : 3327
> free_memory            : 2913
> 
> 
> [root@CentOS4 ~]#  xm dmesg | less
> ERROR: cannot use unconfigured serial port COM1
>  __  __            ____    ___   __   
>  \ \/ /___ _ __   |___ \  / _ \ / /_  
>   \  // _ \ '_ \    __) || | | | '_ \ 
>   /  \  __/ | | |  / __/ | |_| | (_) |
>  /_/\_\___|_| |_| |_____(_)___(_)___/ 
>                                       
>  http://www.cl.cam.ac.uk/netos/xen
>  University of Cambridge Computer Laboratory
> 
>  Xen version 2.0.6 (tongjian@(none)) (gcc version 3.4.3 
> 20050227 (Red Hat 3.4.3-22.1)) Fri Jul  1 02:53:42 CST 2005  
> Latest ChangeSet: information unavailable
> 
> (XEN) WARNING: Only the first 4GB of the physical memory map 
> can be accessed
> (XEN)          by Xen in 32-bit mode. Truncating the memory map...
> (XEN) Physical RAM map:
> (XEN)  0000000000000000 - 00000000000a0000 (usable)
> (XEN)  0000000000100000 - 00000000cffc0000 (usable)
> (XEN)  00000000cffc0000 - 00000000cffcfc00 (ACPI data)
> (XEN)  00000000cffcfc00 - 00000000cffff000 (reserved)
> (XEN)  00000000e0000000 - 00000000fec90000 (reserved)
> (XEN)  00000000fed00000 - 00000000fed00400 (reserved)
> (XEN)  00000000fee00000 - 00000000fee10000 (reserved)
> (XEN)  00000000ffb00000 - 0000000100000000 (reserved)
> (XEN) System RAM: 3327MB (3407232kB)
> (XEN) Xen heap: 10MB (10680kB)
> (XEN) CPU0: Before vendor init, caps: bfebfbff 20100000 
> 00000000, vendor = 0
> (XEN) CPU#0: Physical ID: 0, Logical ID: 0
> (XEN) CPU caps: bfebfbff 20100000 00000000 00000000
> (XEN) found SMP MP-table at 000fe710
> (XEN) ACPI: RSDP (v000 DELL                                   
>    ) @ 0x000fd650
> (XEN) ACPI: RSDT (v001 DELL   PE BKC   0x00000001 MSFT 
> 0x0100000a) @ 0x000fd664
> (XEN) ACPI: FADT (v001 DELL   PE BKC   0x00000001 MSFT 
> 0x0100000a) @ 0x000fd6b0
> (XEN) ACPI: MADT (v001 DELL   PE BKC   0x00000001 MSFT 
> 0x0100000a) @ 0x000fd724
> (XEN) ACPI: SPCR (v001 DELL   PE BKC   0x00000001 MSFT 
> 0x0100000a) @ 0x000fd7cc
> (XEN) ACPI: HPET (v001 DELL   PE BKC   0x00000001 MSFT 
> 0x0100000a) @ 0x000fd81c
> (XEN) ACPI: MCFG (v001 DELL   PE BKC   0x00000001 MSFT 
> 0x0100000a) @ 0x000fd854
> (XEN) ACPI: DSDT (v001 DELL   PE BKC   0x00000001 MSFT 
> 0x0100000e) @ 0x00000000
> (XEN) ACPI: Local APIC address 0xfee00000
> (XEN) ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled)
> (XEN) Processor #0 Unknown CPU [15:4] APIC version 20
> (XEN) ACPI: LAPIC (acpi_id[0x02] lapic_id[0x06] enabled)
> (XEN) Processor #6 Unknown CPU [15:4] APIC version 20
> (XEN) ACPI: LAPIC (acpi_id[0x03] lapic_id[0x01] enabled)
> (XEN) Processor #1 Unknown CPU [15:4] APIC version 20
> [root@CentOS4 ~]# 
> 
>  
> 
>  
> 
> 
> ________________________________
> 
> 使用 MSN Messenger <http://g.msn.com/8HMBCN/2734??PS=47575>  与联机的朋友进行交流
> 
_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

she11c0de she11c0de

2005-Jul-07 09:59 UTC

head link

RE: [Xen-users] Why my system only use 3.3G memory ?

I think it''s maybe a bug, because if Xen 2.0 has 4G memory 
limit, even my Dell 2850 server has 6G memory , Xen 2.0 would use 4G 
memory on it, but it''s just use 3327MB memory.

I have another server Dell 2650 with 4G memory dual Xeon 3.0G CPU, had 
install Redhat 9.0 and Xen 2.0, it''s not have any problem, i has 
running 8 virtual server on it.

Here is my Dell2650 XenLinux system info.

[tongjian@XenServer43 11:59:19 ~ 350]$ xm 
info
system                 
: 
Linux
host                   
: 
XenServer43.testgroups.sina.com.cn
release                
: 
2.6.9-xen0
version                
: #4 Fri Dec 31 19:09:27 CST 
2004
machine                
: 
i686
cores                  
: 2
hyperthreads_per_core  : 
2
cpu_mhz                
: 
3052
memory                 
: 
3967
free_memory            
: 1757

[tongjian@XenServer43 17:35:18 ~ 351]$ xm dmesg | less
ERROR: cannot 
use unconfigured serial port COM1
 __  
__            
____    ___  
 \ \/ /___ _ __   |___ 
\  / _ \ 
  \  // _ \ ''_ \    __) || | | 
|
  /  \  __/ | | |  / __/ | |_| 
|
 /_/\_\___|_| |_| |_____(_)___/ 

 http://www.cl.cam.ac.uk/netos/xen
 University 
of Cambridge Computer Laboratory

 Xen version 2.0 (root@(none)) (gcc 
version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)) Fri Dec 31 19:16:41 CST 
2004
 Latest ChangeSet: information unavailable

(XEN) Initialised 3967MB memory (1015776 pages) on a 3967MB 
machine
(XEN) Xen heap size is 10684KB
(XEN) CPU0: Before vendor 
init, caps: bfebfbff 00000000 00000000, vendor = 0
(XEN) CPU#0: Physical 
ID: 0, Logical ID: 0
(XEN) CPU caps: bfebfbff 00000000 00000000 
00000000
(XEN) found SMP MP-table at 000fe710
(XEN) Memory 
Reservation 0xfe710, 4096 bytes
(XEN) Memory Reservation 0xf0000, 4096 
bytes
(XEN) ACPI: RSDP (v000 
DELL                                      
) @ 0x000fdc40
(XEN) ACPI: RSDT (v001 DELL   
PE2650   0x00000001 MSFT 0x0100000a) @ 0x000fdc54
(XEN) ACPI: 
FADT (v001 DELL   PE2650   0x00000001 MSFT 0x0100000a) 
@ 0x000fdc84
(XEN) ACPI: MADT (v001 DELL   PE2650   
0x00000001 MSFT 0x0100000a) @ 0x000fdcf8
(XEN) ACPI: SPCR (v001 
DELL   PE2650   0x00000001 MSFT 0x0100000a) @ 
0x000fdd80
(XEN) ACPI: DSDT (v001 DELL   PE2650   
0x00000001 MSFT 0x0100000a) @ 0x00000000
(XEN) ACPI: Local APIC address 
0xfee00000
(XEN) ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] 
enabled)
(XEN) Processor #0 Pentium 4(tm) XEON(tm) APIC version 
20
(XEN) ACPI: LAPIC (acpi_id[0x02] lapic_id[0x06] enabled)
(XEN) 
Processor #6 Pentium 4(tm) XEON(tm) APIC version 20
(XEN) ACPI: LAPIC 
(acpi_id[0x03] lapic_id[0x01] enabled)
(XEN) Processor #1 Pentium 4(tm) 
XEON(tm) APIC version 20
(XEN) ACPI: LAPIC (acpi_id[0x04] lapic_id[0x07] 
enabled)
(XEN) Processor #7 Pentium 4(tm) XEON(tm) APIC version 20

&gt;From: "Ian Pratt" 

&gt;To: "she11c0de she11c0de" 
,
&gt;CC: 
,
&gt;Subject: 
RE: [Xen-users] Why my system only use 3.3G memory ?
&gt;Date: Thu, 7 
Jul 2005 09:05:01 +0100
&gt;
&gt;(XEN) Physical RAM 
map:
&gt;(XEN)  0000000000000000 - 00000000000a0000 
(usable)
&gt;(XEN)  0000000000100000 - 00000000cffc0000 
(usable)
&gt;(XEN)  00000000cffc0000 - 00000000cffcfc00 (ACPI 
data)
&gt;(XEN)  00000000cffcfc00 - 00000000cffff000 
(reserved)
&gt;(XEN)  00000000e0000000 - 00000000fec90000 
(reserved)
&gt;(XEN)  00000000fed00000 - 00000000fed00400 
(reserved)
&gt;(XEN)  00000000fee00000 - 00000000fee10000 
(reserved)
&gt;(XEN)  00000000ffb00000 - 0000000100000000 
(reserved)
&gt;(XEN) System RAM: 3327MB (3407232kB)
&gt;
&gt;Your 
BIOS has created a whole at the top of the memory map into which the memory 
mapped PCI devices have been placed, effectively hiding the memory from 
use.
&gt;
&gt;What is slightly odd is that the whole is larger than 
I''ve seen before. I presume its the area between cffff000 and e0000000 
which isn''t listed in the e820 map (everything above cffc0000 is 
unusable).
&gt;
&gt;You''ll have to wait until xen3 and use x86_32pae 
or x86_64 to use more memory.
&gt;
&gt;Ian
&gt;
&gt; &gt; 
-----Original Message-----
&gt; &gt; From: 
xen-users-bounces@lists.xensource.com
&gt; &gt; 
[mailto:xen-users-bounces@lists.xensource.com] On Behalf Of
&gt; &gt; 
she11c0de she11c0de
&gt; &gt; Sent: 07 July 2005 06:50
&gt; &gt; To: 
xen-users@lists.xensource.com
&gt; &gt; Subject: [Xen-users] Why my 
system only use 3.3G memory ?
&gt; &gt;
&gt; &gt; Hi, all
&gt; 
&gt;
&gt; &gt; I have a server used to install Xen-2.0.6 on CentOS 4.1 
i386,
&gt; &gt; hardware is DELL 2850, dual Xeon 3.2G CPU, 6G memory, 
use
&gt; &gt; myself custom compiled xen kernel(dom0 and domU), i know 
xen
&gt; &gt; 2.0 on i386 only use 4G memory, but i found on my 
server,
&gt; &gt; it''s only use 3327M memory, whit''s problem,
who can
help me?
&gt; &gt;
&gt; &gt; Here is some info.
&gt; &gt;
&gt; 
&gt; [root@CentOS4 ~]#  xm info
&gt; &gt; 
system                 
: Linux
&gt; &gt; 
host                   
: CentOS4
&gt; &gt; 
release                : 
2.6.11.10-xen0
&gt; &gt; 
version                : 
#3 Fri Jul 1 02:54:48 CST 2005
&gt; &gt; 
machine                : 
i686
&gt; &gt; 
cores                  : 
2
&gt; &gt; hyperthreads_per_core  : 2
&gt; &gt; 
cpu_mhz                : 
3192
&gt; &gt; 
memory                 
: 3327
&gt; &gt; 
free_memory            : 
2913
&gt; &gt;
&gt; &gt;
&gt; &gt; [root@CentOS4 ~]#  xm 
dmesg | less
&gt; &gt; ERROR: cannot use unconfigured serial port 
COM1
&gt; 
&gt;  __  __            ____    ___   
__
&gt; &gt;  \ \/ /___ _ __   |___ \  / _ 
\ / /_
&gt; &gt;   \  // _ \ ''_ 
\    __) || | | | ''_ \
&gt; &gt;   
/  \  __/ | | |  / __/ | |_| | (_) |
&gt; 
&gt;  /_/\_\___|_| |_| |_____(_)___(_)___/
&gt; &gt;
&gt; 
&gt;  http://www.cl.cam.ac.uk/netos/xen
&gt; 
&gt;  University of Cambridge Computer Laboratory
&gt; 
&gt;
&gt; &gt;  Xen version 2.0.6 (tongjian@(none)) (gcc 
version 3.4.3
&gt; &gt; 20050227 (Red Hat 3.4.3-22.1)) Fri 
Jul  1 02:53:42 CST 2005
&gt; &gt; Latest ChangeSet: 
information unavailable
&gt; &gt;
&gt; &gt; (XEN) WARNING: Only the 
first 4GB of the physical memory map
&gt; &gt; can be accessed
&gt; 
&gt; (XEN)          by 
Xen in 32-bit mode. Truncating the memory map...
&gt; &gt; (XEN) 
Physical RAM map:
&gt; &gt; (XEN)  0000000000000000 - 
00000000000a0000 (usable)
&gt; &gt; (XEN)  0000000000100000 - 
00000000cffc0000 (usable)
&gt; &gt; (XEN)  00000000cffc0000 - 
00000000cffcfc00 (ACPI data)
&gt; &gt; (XEN)  00000000cffcfc00 
- 00000000cffff000 (reserved)
&gt; &gt; 
(XEN)  00000000e0000000 - 00000000fec90000 (reserved)
&gt; 
&gt; (XEN)  00000000fed00000 - 00000000fed00400 
(reserved)
&gt; &gt; (XEN)  00000000fee00000 - 
00000000fee10000 (reserved)
&gt; &gt; (XEN)  00000000ffb00000 
- 0000000100000000 (reserved)
&gt; &gt; (XEN) System RAM: 3327MB 
(3407232kB)
&gt; &gt; (XEN) Xen heap: 10MB (10680kB)
&gt; &gt; (XEN) 
CPU0: Before vendor init, caps: bfebfbff 20100000
&gt; &gt; 00000000, 
vendor = 0
&gt; &gt; (XEN) CPU#0: Physical ID: 0, Logical ID: 0
&gt; 
&gt; (XEN) CPU caps: bfebfbff 20100000 00000000 00000000
&gt; &gt; (XEN) 
found SMP MP-table at 000fe710
&gt; &gt; (XEN) ACPI: RSDP (v000 
DELL
&gt; &gt;    ) @ 0x000fd650
&gt; &gt; (XEN) 
ACPI: RSDT (v001 DELL   PE BKC   0x00000001 
MSFT
&gt; &gt; 0x0100000a) @ 0x000fd664
&gt; &gt; (XEN) ACPI: FADT 
(v001 DELL   PE BKC   0x00000001 MSFT
&gt; &gt; 
0x0100000a) @ 0x000fd6b0
&gt; &gt; (XEN) ACPI: MADT (v001 
DELL   PE BKC   0x00000001 MSFT
&gt; &gt; 
0x0100000a) @ 0x000fd724
&gt; &gt; (XEN) ACPI: SPCR (v001 
DELL   PE BKC   0x00000001 MSFT
&gt; &gt; 
0x0100000a) @ 0x000fd7cc
&gt; &gt; (XEN) ACPI: HPET (v001 
DELL   PE BKC   0x00000001 MSFT
&gt; &gt; 
0x0100000a) @ 0x000fd81c
&gt; &gt; (XEN) ACPI: MCFG (v001 
DELL   PE BKC   0x00000001 MSFT
&gt; &gt; 
0x0100000a) @ 0x000fd854
&gt; &gt; (XEN) ACPI: DSDT (v001 
DELL   PE BKC   0x00000001 MSFT
&gt; &gt; 
0x0100000e) @ 0x00000000
&gt; &gt; (XEN) ACPI: Local APIC address 
0xfee00000
&gt; &gt; (XEN) ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] 
enabled)
&gt; &gt; (XEN) Processor #0 Unknown CPU [15:4] APIC version 
20
&gt; &gt; (XEN) ACPI: LAPIC (acpi_id[0x02] lapic_id[0x06] 
enabled)
&gt; &gt; (XEN) Processor #6 Unknown CPU [15:4] APIC version 
20
&gt; &gt; (XEN) ACPI: LAPIC (acpi_id[0x03] lapic_id[0x01] 
enabled)
&gt; &gt; (XEN) Processor #1 Unknown CPU [15:4] APIC version 
20
&gt; &gt; [root@CentOS4 ~]#
&gt; &gt;
&gt; &gt;
&gt; 
&gt;
&gt; &gt;
&gt; &gt;
&gt; &gt;
&gt; &gt; 
________________________________
&gt; &gt;
&gt; &gt; 浣跨敤 MSN 
Messenger   涓庤仈鏈
虹殑鏈嬪弸杩涜浜ゆ祦
&gt; &gt;

使用 
MSN 
Messenger 与联机的朋友进行交流

--===============1418518594=Content-Type: text/plain;
charset="us-ascii"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Disposition: inline

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users
--===============1418518594==--

Barry Flanagan

2005-Jul-07 11:04 UTC

head link

Re: [Xen-users] Why my system only use 3.3G memory ?

she11c0de she11c0de wrote:> 
> I think it''s maybe a bug, because if Xen 2.0 has 4G memory limit,
> even my Dell 2850 server has 6G memory , Xen 2.0 would use 4G memory on
> it, but it''s just use 3327MB memory.
> 
> I have another server Dell 2650 with 4G memory dual Xeon 3.0G CPU, had
> install Redhat 9.0 and Xen 2.0, it''s not have any problem, i has
running
> 8 virtual server on it.
I have the same problem on a pair of IBM  eServer xSeries 346 (8840)
with 4Gb memory but Xen only sees 3199K

system                 : Linux
host                   : charlie
release                : 2.6.10-xen0
version                : #5 Wed Apr 27 17:45:51 IST 2005
machine                : i686
cores                  : 2
hyperthreads_per_core  : 2
cpu_mhz                : 3200
memory                 : 3199
free_memory            : 1



-- 

-Barry Flanagan

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Gino LV. Ledesma

2005-Jul-07 15:47 UTC

head link

Re: [Xen-users] Why my system only use 3.3G memory ?

I can confirm the same "hole" as she11c0de on a Dell PowerEdge 1850
(ServerWorks chipset) -- only ~3.3G of RAM is seen by the machine out
of the 6GB of RAM installed.

- gino

On 7/7/05, Barry Flanagan <barryf-lists@flanagan.ie>
wrote:> she11c0de she11c0de wrote:
> >
> > I think it''s maybe a bug, because if Xen 2.0 has 4G memory
limit,
> > even my Dell 2850 server has 6G memory , Xen 2.0 would use 4G memory
on
> > it, but it''s just use 3327MB memory.
> >
> > I have another server Dell 2650 with 4G memory dual Xeon 3.0G CPU, had
> > install Redhat 9.0 and Xen 2.0, it''s not have any problem, i
has running
> > 8 virtual server on it.
> 
> I have the same problem on a pair of IBM  eServer xSeries 346 (8840)
> with 4Gb memory but Xen only sees 3199K
> 
> system                 : Linux
> host                   : charlie
> release                : 2.6.10-xen0
> version                : #5 Wed Apr 27 17:45:51 IST 2005
> machine                : i686
> cores                  : 2
> hyperthreads_per_core  : 2
> cpu_mhz                : 3200
> memory                 : 3199
> free_memory            : 1
> 
> 
> 
> --
> 
> -Barry Flanagan
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>
_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Martin Maney

2005-Jul-07 16:25 UTC

head link

Re: [Xen-users] Why my system only use 3.3G memory ?

And all of these are perfectly normal!  Without PAE, the physical
memory space is limited to 4G.  Then the chipset carves out a bit at
the top of that for PCI and AGP and whatever else, and yeah, they do
seem to take a bigger bite than is really necessary, but that does seem
to be normal.

Now that it''s been explained, I''ll be happy to accept any of
that
surplus RAM for safe disposal.  :-)


On Thu, Jul 07, 2005 at 08:47:52AM -0700, Gino LV. Ledesma
wrote:> I can confirm the same "hole" as she11c0de on a Dell PowerEdge
1850
> (ServerWorks chipset) -- only ~3.3G of RAM is seen by the machine out
> of the 6GB of RAM installed.
> 
> - gino
> 
> On 7/7/05, Barry Flanagan <barryf-lists@flanagan.ie> wrote:
> > she11c0de she11c0de wrote:
> > >
> > > I think it''s maybe a bug, because if Xen 2.0 has 4G
memory limit,
> > > even my Dell 2850 server has 6G memory , Xen 2.0 would use 4G
memory on
> > > it, but it''s just use 3327MB memory.
> > >
> > > I have another server Dell 2650 with 4G memory dual Xeon 3.0G
CPU, had
> > > install Redhat 9.0 and Xen 2.0, it''s not have any
problem, i has running
> > > 8 virtual server on it.
> > 
> > I have the same problem on a pair of IBM  eServer xSeries 346 (8840)
> > with 4Gb memory but Xen only sees 3199K
> > 
> > system                 : Linux
> > host                   : charlie
> > release                : 2.6.10-xen0
> > version                : #5 Wed Apr 27 17:45:51 IST 2005
> > machine                : i686
> > cores                  : 2
> > hyperthreads_per_core  : 2
> > cpu_mhz                : 3200
> > memory                 : 3199
> > free_memory            : 1
> > 
> > 
> > 
> > --
> > 
> > -Barry Flanagan
> > 
> > _______________________________________________
> > Xen-users mailing list
> > Xen-users@lists.xensource.com
> > http://lists.xensource.com/xen-users
> >
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
-- 
Now people have pondered this time and again (Who dies? Everyone dies)
We suspect that we''re more than mere mortal remains (Oh, everyone dies)
Wise men and prophets they''ve all had their say
  on the nature of our afterlives
But in case there''s no beer there we''ll have one more round
(Oh everyone dies)
 -- James Keelaghan in "Who Dies?", an upbeat song about mortality


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Barry Flanagan

2005-Jul-07 16:34 UTC

head link

Re: [Xen-users] Why my system only use 3.3G memory ?

Martin Maney wrote:> And all of these are perfectly normal!  Without PAE, the physical
> memory space is limited to 4G.  Then the chipset carves out a bit at
> the top of that for PCI and AGP and whatever else, and yeah, they do
> seem to take a bigger bite than is really necessary, but that does seem
> to be normal.
> 
> Now that it''s been explained, I''ll be happy to accept any
of that
> surplus RAM for safe disposal.  :-)
This is Xen specific. If I boot straight Debian I get all 4Gb.

-- 

-Barry Flanagan

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Mark Williamson

2005-Jul-07 17:34 UTC

head link

Re: [Xen-users] Why my system only use 3.3G memory ?

> > Now that it''s been explained, I''ll be happy to
accept any of that
> > surplus RAM for safe disposal.  :-)
>
> This is Xen specific. If I boot straight Debian I get all 4Gb.
It shouldn''t be Xen-specific but it *is* non-PAE specific.  i.e.
Vanilla Linux
can support PAE to access all of your memory.  Xen 2.0 doesn''t support
PAE so
it won''t work.  On Xen 3.0 you''ll probably see all of it.

Cheers,
Mark

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Petersson, Mats

2005-Jul-08 08:58 UTC

head link

RE: [Xen-devel] RE: [Xen-users] Why my system only use 3.3G memory ?

It is certainly not a bug as such. It's a "Missing feature". Xen
2.0 does not support PAE (Page Address Extension). The PAE extension allows the
processor to address memory beyond 4GB when accessing memory through the paged
memory management unit (MMU or PMMU depending on who you talk to). This means
that although the processor has a virtual limit of 4GB, it can map memory from
beyond 4GB to map that into the virtual address space of the kernel. However,
without PAE, the processor can only access 4GB and that's it, anything
beyond that is outside it's reach.

The other part of the problem is that the BIOS maps PCI devices into the first
4GB of memory. Depending on how clever (or not) the BIOS is, it may eat more
memory than it MUST. But there are several factors to take into account here.
For example, some devices that require large address spaces will often also
require that the device is evenly aligned to it's mapped size, so something
that has a 64MB address space, should also be aligned to 64MB. This means that
there may well be a hole of almost 64MB after this map. Some devices, such as
graphics cards, can easily use up 256 or 512MB this way. [Of course, if the BIOS
is clever, it would use the remaining part for some other mappings, but it's
not always that the BIOS is clever enough to do this].

So, your 700 or so MB that are "missing" is caused by the PCI
mappings. Generally speaking, this space is "non-RAM", so any access
to the unused areas in this space will just be lost.

You can work around this by running Xen 3.0, but the Xen 3.0 is yet to be
released, so it's not suitable for production environments. It does,
however, support both 64-bit and PAE addressing of the memory, depending on the
type of processor you have.

Obviously, even with PAE, you will not be able to use ALL of the 4GB, because
some of it will be mapped to the PCI hardware devices. But any "hole"
between devices in the PCI map can be mapped in as RAM, so the kernel could
possibly use up the gaps in the space with memory from above 4GB, rather than
just "loosing" it.

I hope this clarifies the situation.

--
Mats

________________________________

	From: xen-devel-bounces@lists.xensource.com
[mailto:xen-devel-bounces@lists.xensource.com] On Behalf Of she11c0de she11c0de
	Sent: 07 July 2005 11:00
	To: m+Ian.Pratt@cl.cam.ac.uk; xen-users@lists.xensource.com
	Cc: xen-devel@lists.xensource.com
	Subject: [Xen-devel] RE: [Xen-users] Why my system only use 3.3G memory ?
	
	

	
	I think it's maybe a bug, because if Xen 2.0 has 4G memory limit, even my
Dell 2850 server has 6G memory , Xen 2.0 would use 4G memory on it, but it's
just use 3327MB memory.

	I have another server Dell 2650 with 4G memory dual Xeon 3.0G CPU, had install
Redhat 9.0 and Xen 2.0, it's not have any problem, i has running 8 virtual
server on it.

	Here is my Dell2650 XenLinux system info.

	[tongjian@XenServer43 11:59:19 ~ 350]$ xm info
	system                 : Linux
	host                   : XenServer43.testgroups.sina.com.cn
	release                : 2.6.9-xen0
	version                : #4 Fri Dec 31 19:09:27 CST 2004
	machine                : i686
	cores                  : 2
	hyperthreads_per_core  : 2
	cpu_mhz                : 3052
	memory                 : 3967
	free_memory            : 1757
	

	[tongjian@XenServer43 17:35:18 ~ 351]$ xm dmesg | less
	ERROR: cannot use unconfigured serial port COM1
	 __  __            ____    ___  
	 \ \/ /___ _ __   |___ \  / _ \ 
	  \  // _ \ '_ \    __) || | | |
	  /  \  __/ | | |  / __/ | |_| |
	 /_/\_\___|_| |_| |_____(_)___/ 
	                                
	 http://www.cl.cam.ac.uk/netos/xen
	 University of Cambridge Computer Laboratory

	 Xen version 2.0 (root@(none)) (gcc version 3.2.2 20030222 (Red Hat Linux
3.2.2-5)) Fri Dec 31 19:16:41 CST 2004
	 Latest ChangeSet: information unavailable

	(XEN) Initialised 3967MB memory (1015776 pages) on a 3967MB machine
	(XEN) Xen heap size is 10684KB
	(XEN) CPU0: Before vendor init, caps: bfebfbff 00000000 00000000, vendor = 0
	(XEN) CPU#0: Physical ID: 0, Logical ID: 0
	(XEN) CPU caps: bfebfbff 00000000 00000000 00000000
	(XEN) found SMP MP-table at 000fe710
	(XEN) Memory Reservation 0xfe710, 4096 bytes
	(XEN) Memory Reservation 0xf0000, 4096 bytes
	(XEN) ACPI: RSDP (v000 DELL                                      ) @ 0x000fdc40
	(XEN) ACPI: RSDT (v001 DELL   PE2650   0x00000001 MSFT 0x0100000a) @ 0x000fdc54
	(XEN) ACPI: FADT (v001 DELL   PE2650   0x00000001 MSFT 0x0100000a) @ 0x000fdc84
	(XEN) ACPI: MADT (v001 DELL   PE2650   0x00000001 MSFT 0x0100000a) @ 0x000fdcf8
	(XEN) ACPI: SPCR (v001 DELL   PE2650   0x00000001 MSFT 0x0100000a) @ 0x000fdd80
	(XEN) ACPI: DSDT (v001 DELL   PE2650   0x00000001 MSFT 0x0100000a) @ 0x00000000
	(XEN) ACPI: Local APIC address 0xfee00000
	(XEN) ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled)
	(XEN) Processor #0 Pentium 4(tm) XEON(tm) APIC version 20
	(XEN) ACPI: LAPIC (acpi_id[0x02] lapic_id[0x06] enabled)
	(XEN) Processor #6 Pentium 4(tm) XEON(tm) APIC version 20
	(XEN) ACPI: LAPIC (acpi_id[0x03] lapic_id[0x01] enabled)
	(XEN) Processor #1 Pentium 4(tm) XEON(tm) APIC version 20
	(XEN) ACPI: LAPIC (acpi_id[0x04] lapic_id[0x07] enabled)
	(XEN) Processor #7 Pentium 4(tm) XEON(tm) APIC version 20

	 

	 

	
	 




	>From: "Ian Pratt" <m+Ian.Pratt@cl.cam.ac.uk>
	>To: "she11c0de she11c0de"
<she11c0de@hotmail.com>,<xen-users@lists.xensource.com>
	>CC: <xen-devel@lists.xensource.com>,<ian.pratt@cl.cam.ac.uk>
	>Subject: RE: [Xen-users] Why my system only use 3.3G memory ?
	>Date: Thu, 7 Jul 2005 09:05:01 +0100
	>
	>(XEN) Physical RAM map:
	>(XEN)  0000000000000000 - 00000000000a0000 (usable)
	>(XEN)  0000000000100000 - 00000000cffc0000 (usable)
	>(XEN)  00000000cffc0000 - 00000000cffcfc00 (ACPI data)
	>(XEN)  00000000cffcfc00 - 00000000cffff000 (reserved)
	>(XEN)  00000000e0000000 - 00000000fec90000 (reserved)
	>(XEN)  00000000fed00000 - 00000000fed00400 (reserved)
	>(XEN)  00000000fee00000 - 00000000fee10000 (reserved)
	>(XEN)  00000000ffb00000 - 0000000100000000 (reserved)
	>(XEN) System RAM: 3327MB (3407232kB)
	>
	>Your BIOS has created a whole at the top of the memory map into which the
memory mapped PCI devices have been placed, effectively hiding the memory from
use.
	>
	>What is slightly odd is that the whole is larger than I've seen before.
I presume its the area between cffff000 and e0000000 which isn't listed in
the e820 map (everything above cffc0000 is unusable).
	>
	>You'll have to wait until xen3 and use x86_32pae or x86_64 to use more
memory.
	>
	>Ian
	>
	> > -----Original Message-----
	> > From: xen-users-bounces@lists.xensource.com
	> > [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of
	> > she11c0de she11c0de
	> > Sent: 07 July 2005 06:50
	> > To: xen-users@lists.xensource.com
	> > Subject: [Xen-users] Why my system only use 3.3G memory ?
	> >
	> > Hi, all
	> >
	> > I have a server used to install Xen-2.0.6 on CentOS 4.1 i386,
	> > hardware is DELL 2850, dual Xeon 3.2G CPU, 6G memory, use
	> > myself custom compiled xen kernel(dom0 and domU), i know xen
	> > 2.0 on i386 only use 4G memory, but i found on my server,
	> > it's only use 3327M memory, whit's problem, who can help me?
	> >
	> > Here is some info.
	> >
	> > [root@CentOS4 ~]#  xm info
	> > system                 : Linux
	> > host                   : CentOS4
	> > release                : 2.6.11.10-xen0
	> > version                : #3 Fri Jul 1 02:54:48 CST 2005
	> > machine                : i686
	> > cores                  : 2
	> > hyperthreads_per_core  : 2
	> > cpu_mhz                : 3192
	> > memory                 : 3327
	> > free_memory            : 2913
	> >
	> >
	> > [root@CentOS4 ~]#  xm dmesg | less
	> > ERROR: cannot use unconfigured serial port COM1
	> >  __  __            ____    ___   __
	> >  \ \/ /___ _ __   |___ \  / _ \ / /_
	> >   \  // _ \ '_ \    __) || | | | '_ \
	> >   /  \  __/ | | |  / __/ | |_| | (_) |
	> >  /_/\_\___|_| |_| |_____(_)___(_)___/
	> >
	> >  http://www.cl.cam.ac.uk/netos/xen
	> >  University of Cambridge Computer Laboratory
	> >
	> >  Xen version 2.0.6 (tongjian@(none)) (gcc version 3.4.3
	> > 20050227 (Red Hat 3.4.3-22.1)) Fri Jul  1 02:53:42 CST 2005
	> > Latest ChangeSet: information unavailable
	> >
	> > (XEN) WARNING: Only the first 4GB of the physical memory map
	> > can be accessed
	> > (XEN)          by Xen in 32-bit mode. Truncating the memory map...
	> > (XEN) Physical RAM map:
	> > (XEN)  0000000000000000 - 00000000000a0000 (usable)
	> > (XEN)  0000000000100000 - 00000000cffc0000 (usable)
	> > (XEN)  00000000cffc0000 - 00000000cffcfc00 (ACPI data)
	> > (XEN)  00000000cffcfc00 - 00000000cffff000 (reserved)
	> > (XEN)  00000000e0000000 - 00000000fec90000 (reserved)
	> > (XEN)  00000000fed00000 - 00000000fed00400 (reserved)
	> > (XEN)  00000000fee00000 - 00000000fee10000 (reserved)
	> > (XEN)  00000000ffb00000 - 0000000100000000 (reserved)
	> > (XEN) System RAM: 3327MB (3407232kB)
	> > (XEN) Xen heap: 10MB (10680kB)
	> > (XEN) CPU0: Before vendor init, caps: bfebfbff 20100000
	> > 00000000, vendor = 0
	> > (XEN) CPU#0: Physical ID: 0, Logical ID: 0
	> > (XEN) CPU caps: bfebfbff 20100000 00000000 00000000
	> > (XEN) found SMP MP-table at 000fe710
	> > (XEN) ACPI: RSDP (v000 DELL
	> >    ) @ 0x000fd650
	> > (XEN) ACPI: RSDT (v001 DELL   PE BKC   0x00000001 MSFT
	> > 0x0100000a) @ 0x000fd664
	> > (XEN) ACPI: FADT (v001 DELL   PE BKC   0x00000001 MSFT
	> > 0x0100000a) @ 0x000fd6b0
	> > (XEN) ACPI: MADT (v001 DELL   PE BKC   0x00000001 MSFT
	> > 0x0100000a) @ 0x000fd724
	> > (XEN) ACPI: SPCR (v001 DELL   PE BKC   0x00000001 MSFT
	> > 0x0100000a) @ 0x000fd7cc
	> > (XEN) ACPI: HPET (v001 DELL   PE BKC   0x00000001 MSFT
	> > 0x0100000a) @ 0x000fd81c
	> > (XEN) ACPI: MCFG (v001 DELL   PE BKC   0x00000001 MSFT
	> > 0x0100000a) @ 0x000fd854
	> > (XEN) ACPI: DSDT (v001 DELL   PE BKC   0x00000001 MSFT
	> > 0x0100000e) @ 0x00000000
	> > (XEN) ACPI: Local APIC address 0xfee00000
	> > (XEN) ACPI: LAPIC (acpi_id[0x01] lapic_id[0x00] enabled)
	> > (XEN) Processor #0 Unknown CPU [15:4] APIC version 20
	> > (XEN) ACPI: LAPIC (acpi_id[0x02] lapic_id[0x06] enabled)
	> > (XEN) Processor #6 Unknown CPU [15:4] APIC version 20
	> > (XEN) ACPI: LAPIC (acpi_id[0x03] lapic_id[0x01] enabled)
	> > (XEN) Processor #1 Unknown CPU [15:4] APIC version 20
	> > [root@CentOS4 ~]#
	> >
	> >
	> >
	> >
	> >
	> >
	> > ________________________________
	> >
	> > 浣跨敤 MSN Messenger <http://g.msn.com/8HMBCN/2734??PS=47575> 
涓庤仈鏈虹殑鏈嬪弸杩涜浜ゆ祦
	> >
	

________________________________

	使用 MSN Messenger <http://g.msn.com/8HMACN/2737??PS=47575>  与联机的朋友进行交流 


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Keir Fraser

2005-Jul-08 09:25 UTC

head link

Re: [Xen-devel] RE: [Xen-users] Why my system only use 3.3G memory ?

On 8 Jul 2005, at 09:58, Petersson, Mats wrote:
> You can work around this by running Xen 3.0, but the Xen 3.0 is yet to 
> be released, so it''s not suitable for production environments. It 
> does, however, support both 64-bit and PAE addressing of the memory, 
> depending on the type of processor you have.
>
> Obviously, even with PAE, you will not be able to use ALL of the 4GB, 
> because some of it will be mapped to the PCI hardware devices. But any 
> "hole" between devices in the PCI map can be mapped in as RAM, so
the
> kernel could possibly use up the gaps in the space with memory from 
> above 4GB, rather than just "loosing" it.
The PAE support isn''t fully baked yet anyway. We''re waiting on
fixed-up
PAE patches for XenLinux from Gerd Knorr. Should be happening ''real 
soon now''. ;-)

  -- Keir


_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

Ronald G. Minnich

2005-Jul-08 14:50 UTC

head link

RE: [Xen-devel] RE: [Xen-users] Why my system only use 3.3G memory ?

On Fri, 8 Jul 2005, Petersson, Mats wrote:
> The other part of the problem is that the BIOS maps PCI devices into the
> first 4GB of memory. Depending on how clever (or not) the BIOS is, it
> may eat more memory than it MUST. But there are several factors to take
> into account here. For example, some devices that require large address
> spaces will often also require that the device is evenly aligned to
it''s
> mapped size, so something that has a 64MB address space, should also be
> aligned to 64MB. 
This is actually a PCI requirement. The address has to be aligned on its 
granularity. Really silly. 
>This means that there may well be a hole of almost 64MB
> after this map. Some devices, such as graphics cards, can easily use up
> 256 or 512MB this way. [Of course, if the BIOS is clever, it would use
> the remaining part for some other mappings, but it''s not always
that the
> BIOS is clever enough to do this].
BIOSes are generally dumb as dirt on this score. LinuxBIOS is pretty smart 
about it, however. 
> Obviously, even with PAE, you will not be able to use ALL of the 4GB,
> because some of it will be mapped to the PCI hardware devices. But any
> "hole" between devices in the PCI map can be mapped in as RAM, so
the
> kernel could possibly use up the gaps in the space with memory from
> above 4GB, rather than just "loosing" it.
it''s more complex than that. Some chipsets allow remapping the ram that
is
"lost" to pci mappings up above 4 GB. There''s no end of weird
tricks in
this space. 

ron

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xensource.com
http://lists.xensource.com/xen-devel

Xen users - Jul 2005 - Why my system only use 3.3G memory ?

[Xen-users] Why my system only use 3.3G memory ?

[Xen-users] Why my system only use 3.3G memory ?

RE: [Xen-users] Why my system only use 3.3G memory ?

RE: [Xen-users] Why my system only use 3.3G memory ?

Re: [Xen-users] Why my system only use 3.3G memory ?

Re: [Xen-users] Why my system only use 3.3G memory ?

Re: [Xen-users] Why my system only use 3.3G memory ?

Re: [Xen-users] Why my system only use 3.3G memory ?

Re: [Xen-users] Why my system only use 3.3G memory ?

RE: [Xen-devel] RE: [Xen-users] Why my system only use 3.3G memory ?

Re: [Xen-devel] RE: [Xen-users] Why my system only use 3.3G memory ?

RE: [Xen-devel] RE: [Xen-users] Why my system only use 3.3G memory ?