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Emmanuel COURCELLE

2012-Jan-02 14:50 UTC

Which kernel may I compile ?

Hello everybody

We are currently using xen 4.0 on a Debian stable (kernel 
2.6.32-5-xen-amd64), it has been working without any trouble for several 
years.
But now we would like to have a domU with 96Gb memory (paravirtualized, 
ie NOT hvm)
It is not possible with our kernel, because of the limitation to 32Gb 
for a domU
So I tried to compile the 3.1.6 kernel, with the following grub.cfg entry:

menuentry "Xen 4.0 KERNEL 3.1.6" {
     insmod ext2
     set root=''(hd1,1)''
     multiboot /boot/xen-4.0-amd64.gz dom0_mem=512M dom0_max_vcpus=1 
dom0_vcpus_pin loglvl=all guest_loglvl=all
     search --no-floppy --fs-uuid --set xxx
     module /boot/vmlinuz-3.1.6 dummy=dummy root=UUID=xxx ro
     module /boot/initrd.img-3.1.6
}

This worked well with the 2.6.32 kernel, but I get a panic with the 
3.1.6 kernel (cannot find the root FS)
The machine boots correctly the new 3.1.6 kernel when I remove the 
xen-related entry, so I think my compilation is correct.

Well, here is the question: Which kernel should I compile to drop this 
32Gb limitation without upgrading xen itsef ?
(I would want to avoid upgrading to debian testing).

Thanks in advance for your answers !

-- 
Emmanuel COURCELLE                emmanuel.courcelle@toulouse.inra.fr
L.I.P.M. (UMR CNRS-INRA 2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE

David TECHER

2012-Jan-02 15:27 UTC

head link

Re : Which kernel may I compile ?

I do not try this but perhaps it could help


cp /boot/config-2.6.32-5-xen-amd64 .config


yes "" | make oldconfig


________________________________
 De : Emmanuel COURCELLE <emmanuel.courcelle@toulouse.inra.fr>
À : xen-users@lists.xensource.com 
Envoyé le : Lundi 2 Janvier 2012 15h50
Objet : [Xen-users] Which kernel may I compile ?
 
Hello everybody

We are currently using xen 4.0 on a Debian stable (kernel 2.6.32-5-xen-amd64),
it has been working without any trouble for several years.
But now we would like to have a domU with 96Gb memory (paravirtualized, ie NOT
hvm)
It is not possible with our kernel, because of the limitation to 32Gb for a domU
So I tried to compile the 3.1.6 kernel, with the following grub.cfg entry:

menuentry "Xen 4.0 KERNEL 3.1.6" {
    insmod ext2
    set root=''(hd1,1)''
    multiboot /boot/xen-4.0-amd64.gz dom0_mem=512M dom0_max_vcpus=1
dom0_vcpus_pin loglvl=all guest_loglvl=all
    search --no-floppy --fs-uuid --set xxx
    module /boot/vmlinuz-3.1.6 dummy=dummy root=UUID=xxx ro
    module /boot/initrd.img-3.1.6
}

This worked well with the 2.6.32 kernel, but I get a panic with the 3.1.6 kernel
(cannot find the root FS)
The machine boots correctly the new 3.1.6 kernel when I remove the xen-related
entry, so I think my compilation is correct.

Well, here is the question: Which kernel should I compile to drop this 32Gb
limitation without upgrading xen itsef ?
(I would want to avoid upgrading to debian testing).

Thanks in advance for your answers !

-- Emmanuel COURCELLE                emmanuel.courcelle@toulouse.inra.fr
L.I.P.M. (UMR CNRS-INRA 2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE


_______________________________________________
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

Emmanuel COURCELLE

2012-Jan-02 16:02 UTC

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Re: Re : Which kernel may I compile ?

Emmanuel COURCELLE

2012-Jan-03 10:01 UTC

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Re: Re : Which kernel may I compile ?

Hello guys

I tried the procedure described here: 
http://wiki.xen.org/wiki/Compiling_Kernel_2.6.32
but it did not work:


# git clone git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git 
linux-2.6-xen
Cloning into linux-2.6-xen...
remote: Counting objects: 2265273, done.
remote: Compressing objects: 100% (360682/360682), done.
remote: Total 2265273 (delta 1892504), reused 2255753 (delta 1883089)
Receiving objects: 100% (2265273/2265273), 448.49 MiB | 2.45 MiB/s, done.
Resolving deltas: 100% (1892504/1892504), done.

# cd linux-2.6-xen/

# git checkout -b xen/stable-2.6.32.x origin/xen/stable-2.6.32.x
fatal: git checkout: updating paths is incompatible with switching branches.
Did you intend to checkout ''origin/xen/stable-2.6.32.x'' which
can not be
resolved as commit?


I am not a git-guru, so I do not understand the message...

Thanks for your help !!!

-- 
Emmanuel COURCELLE                emmanuel.courcelle@toulouse.inra.fr
L.I.P.M. (UMR CNRS-INRA 2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE

David TECHER

2012-Jan-04 10:57 UTC

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Re : Re : Which kernel may I compile ?

Hi Emmanuel,

Sorry not to reply to your last mail.

Jeremy maintains the branch 2.6.32 so you can download the last stable
2.6.32.50.

Do not use git if you are not used to using it.


Two options to download


1) Use Firefox, safari ....go on 

http://git.kernel.org/?p=linux/kernel/git/jeremy/xen.git;a=shortlog;h=refs/heads/xen/next-2.6.32

and click on "snapshot" for 2.6.32.50 to dowload the tar.gz


2) Command line (I think this is the option you will use :) )


wget
"http://git.kernel.org/?p=linux/kernel/git/jeremy/xen.git;a=snapshot;h=60b1e4f20a6cf45f07d2aef7eecd7fd58007ff1e;sf=tgz"
-O linux-2.6.32.50.tar.gz

tar xvzf linux-2.6.32.50.tar.gz

cd linux-????

Then


use config or oldconfig as you need (make oldconfig, make menuconfig as you
need....)


then build the kernel. These are the lines I am used to building the kernel -
the old way -  not tested for this kernel but should work :)


make -j4 bzImage modules
make install modules_install
mkinitramfs -o /boot/config-2.6.32.50 2.6.32.50
update-grub




________________________________
 De : Emmanuel COURCELLE <emmanuel.courcelle@toulouse.inra.fr>
À : xen-users@lists.xensource.com 
Envoyé le : Mardi 3 Janvier 2012 11h01
Objet : Re: [Xen-users] Re :  Which kernel may I compile ?
 
Hello guys

I tried the procedure described here:
http://wiki.xen.org/wiki/Compiling_Kernel_2.6.32
but it did not work:


# git clone git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git
linux-2.6-xen
Cloning into linux-2.6-xen...
remote: Counting objects: 2265273, done.
remote: Compressing objects: 100% (360682/360682), done.
remote: Total 2265273 (delta 1892504), reused 2255753 (delta 1883089)
Receiving objects: 100% (2265273/2265273), 448.49 MiB | 2.45 MiB/s, done.
Resolving deltas: 100% (1892504/1892504), done.

# cd linux-2.6-xen/

# git checkout -b xen/stable-2.6.32.x origin/xen/stable-2.6.32.x
fatal: git checkout: updating paths is incompatible with switching branches.
Did you intend to checkout ''origin/xen/stable-2.6.32.x'' which
can not be resolved as commit?


I am not a git-guru, so I do not understand the message...

Thanks for your help !!!

-- Emmanuel COURCELLE                emmanuel.courcelle@toulouse.inra.fr
L.I.P.M. (UMR CNRS-INRA 2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE


_______________________________________________
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

Emmanuel COURCELLE

2012-Jan-05 09:09 UTC

head link

Re: Re : Re : Which kernel may I compile ?

Hi David
thanks for your answer.

I did exactly as suggested:

1/ download the 2.6.32.50 kernel
2/ cd /usr/src/xen...
3/ cp /boot/config-2.6.32-5-xen-amd64 .config
4/ vi .config and change CONFIG_XEN_MAX_DOMAIN_MEMORY=32 to 
CONFIG_XEN_MAX_DOMAIN_MEMORY=128
5/ make oldconfig
6/ make, mkinitrd, update-grub2
7/ reboot:
        ==> reboot with the new kernel alone (ie WITHOUT the xen 
hypervisor): OK
        ==> reboot with the xen hypervisor: the xen stage is OK, but 
after memory scrub the kernel is loaded, and it runs in panic after a 
couple of seconds, telling that it cannot find root fs VFS block(0,0) 
not found or something like this (after 1 second the screen blanks and 
the machine automatically reboots, so it is difficult to read the 
precise message).

So the question is:

A/ Do I make something wrong ?
B/ If not, do I have a problem with the CONFIG_XEN_MAX_DOMAIN_MEMORY or 
the xen version ?

The server is a Dell Poweredge R710, 2CPUS with 6 cores each, 128Gb memory
The xen version is:

# xm info
host                   : moxen
release                : 2.6.32-5-xen-amd64
version                : #1 SMP Mon Oct 3 07:53:54 UTC 2011
machine                : x86_64
nr_cpus                : 12
nr_nodes               : 2
cores_per_socket       : 6
threads_per_core       : 1
cpu_mhz                : 2660
hw_caps                : 
bfebfbff:2c100800:00000000:00001f40:029ee3ff:00000000:00000001:00000000
virt_caps              : hvm hvm_directio
total_memory           : 131059
free_memory            : 9092
node_to_cpu            : node0:0,2,4,6,8,10
                          node1:1,3,5,7,9,11
node_to_memory         : node0:6
                          node1:9086
node_to_dma32_mem      : node0:0
                          node1:2990
max_node_id            : 1
xen_major              : 4
xen_minor              : 0
xen_extra              : .1
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32 
hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          : unavailable
xen_commandline        : dom0_mem=512M dom0_max_vcpus=1 dom0_vcpus_pin 
loglvl=all guest_loglvl=all
cc_compiler            : gcc version 4.4.5 (Debian 4.4.5-8)
cc_compile_by          : waldi
cc_compile_domain      : debian.org
cc_compile_date        : Sun Nov  6 09:42:15 CET 2011
xend_config_format     : 4


The grub entries are (the first two entries work, the last ends in a panic)

menuentry ''Debian GNU/Linux, with Linux 2.6.32.50'' --class
debian
--class gnu-linux --class gnu --class os {
     insmod part_msdos
     insmod ext2
     set root=''(hd2,msdos1)''
     search --no-floppy --fs-uuid --set 1939b8fd-e856-4762-a6ca-76e0b9be0f36
     echo    ''Loading Linux 2.6.32.50 ...''
     linux    /boot/vmlinuz-2.6.32.50 
root=UUID=1939b8fd-e856-4762-a6ca-76e0b9be0f36 ro  quiet
     echo    ''Loading initial ramdisk ...''
     initrd    /boot/initrd.img-2.6.32.50
}

menuentry "Xen 4.0" {
     insmod ext2
     set root=''(hd1,1)''
     multiboot /boot/xen-4.0-amd64.gz dom0_mem=512M dom0_max_vcpus=1 
dom0_vcpus_pin loglvl=all guest_loglvl=all
     search --no-floppy --fs-uuid --set 1939b8fd-e856-4762-a6ca-76e0b9be0f36
     module /boot/vmlinuz-2.6.32-5-xen-amd64 dummy=dummy 
root=UUID=1939b8fd-e856-4762-a6ca-76e0b9be0f36 ro
     module /boot/initrd.img-2.6.32-5-xen-amd64
}

menuentry "Xen 4.0 2.6.32.50" {
     insmod ext2
     set root=''(hd1,1)''
     multiboot /boot/xen-4.0-amd64.gz dom0_mem=512M dom0_max_vcpus=1 
dom0_vcpus_pin loglvl=all guest_loglvl=all
     search --no-floppy --fs-uuid --set 1939b8fd-e856-4762-a6ca-76e0b9be0f36
     module /boot/vmlinuz-2.6.32.50 dummy=dummy 
root=UUID=1939b8fd-e856-4762-a6ca-76e0b9be0f36 ro
     module /boot/initrd.img-2.6.32.50
}

I attach to this mail the two configuration files (one provided by 
Debian, the other is the output of make oldconfig)

Thanks again for your help !

-- 
Emmanuel COURCELLE                emmanuel.courcelle@toulouse.inra.fr
L.I.P.M. (UMR CNRS-INRA 2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE



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

David TECHER

2012-Jan-05 13:01 UTC

head link

Re : Re : Re : Which kernel may I compile ?

Emmanuel,

Do you''ve got

"Kernel Panic - not syncing: VFS: Unable to mount root fs on
unknown-block(0,0)" ???????

I think you should have a look on
http://askubuntu.com/questions/41930/kernel-panic-not-syncing-vfs-unable-to-mount-root-fs-on-unknown-block0-0

if I understand, you should do something like

update-initramfs -u -k 2.6.32.50

update-grub



________________________________
 De : Emmanuel COURCELLE <emmanuel.courcelle@toulouse.inra.fr>
À : David TECHER <davidtecher@yahoo.fr> 
Cc : "xen-users@lists.xensource.com"
<xen-users@lists.xensource.com>
Envoyé le : Jeudi 5 Janvier 2012 10h09
Objet : Re: [Xen-users] Re :  Re :  Which kernel may I compile ?
 
Hi David
thanks for your answer.

I did exactly as suggested:

1/ download the 2.6.32.50 kernel
2/ cd /usr/src/xen...
3/ cp /boot/config-2.6.32-5-xen-amd64 .config
4/ vi .config and change CONFIG_XEN_MAX_DOMAIN_MEMORY=32 to
CONFIG_XEN_MAX_DOMAIN_MEMORY=128
5/ make oldconfig
6/ make, mkinitrd, update-grub2
7/ reboot:
       ==> reboot with the new kernel alone (ie WITHOUT the xen hypervisor):
OK
       ==> reboot with the xen hypervisor: the xen stage is OK, but after
memory scrub the kernel is loaded, and it runs in panic after a couple of
seconds, telling that it cannot find root fs VFS block(0,0) not found or
something like this (after 1 second the screen blanks and the machine
automatically reboots, so it is difficult to read the precise message).

So the question is:

A/ Do I make something wrong ?
B/ If not, do I have a problem with the CONFIG_XEN_MAX_DOMAIN_MEMORY or the xen
version ?

The server is a Dell Poweredge R710, 2CPUS with 6 cores each, 128Gb memory
The xen version is:

# xm info
host                   : moxen
release                : 2.6.32-5-xen-amd64
version                : #1 SMP Mon Oct 3 07:53:54 UTC 2011
machine                : x86_64
nr_cpus                : 12
nr_nodes               : 2
cores_per_socket       : 6
threads_per_core       : 1
cpu_mhz                : 2660
hw_caps                :
bfebfbff:2c100800:00000000:00001f40:029ee3ff:00000000:00000001:00000000
virt_caps              : hvm hvm_directio
total_memory           : 131059
free_memory            : 9092
node_to_cpu            : node0:0,2,4,6,8,10
                         node1:1,3,5,7,9,11
node_to_memory         : node0:6
                         node1:9086
node_to_dma32_mem      : node0:0
                         node1:2990
max_node_id            : 1
xen_major              : 4
xen_minor              : 0
xen_extra              : .1
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32
hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          : unavailable
xen_commandline        : dom0_mem=512M dom0_max_vcpus=1 dom0_vcpus_pin
loglvl=all guest_loglvl=all
cc_compiler            : gcc version 4.4.5 (Debian 4.4.5-8)
cc_compile_by          : waldi
cc_compile_domain      : debian.org
cc_compile_date        : Sun Nov  6 09:42:15 CET 2011
xend_config_format     : 4


The grub entries are (the first two entries work, the last ends in a panic)

menuentry ''Debian GNU/Linux, with Linux 2.6.32.50'' --class
debian --class gnu-linux --class gnu --class os {
    insmod part_msdos
    insmod ext2
    set root=''(hd2,msdos1)''
    search --no-floppy --fs-uuid --set 1939b8fd-e856-4762-a6ca-76e0b9be0f36
    echo    ''Loading Linux 2.6.32.50 ...''
    linux    /boot/vmlinuz-2.6.32.50
root=UUID=1939b8fd-e856-4762-a6ca-76e0b9be0f36 ro  quiet
    echo    ''Loading initial ramdisk ...''
    initrd    /boot/initrd.img-2.6.32.50
}

menuentry "Xen 4.0" {
    insmod ext2
    set root=''(hd1,1)''
    multiboot /boot/xen-4.0-amd64.gz dom0_mem=512M dom0_max_vcpus=1
dom0_vcpus_pin loglvl=all guest_loglvl=all
    search --no-floppy --fs-uuid --set 1939b8fd-e856-4762-a6ca-76e0b9be0f36
    module /boot/vmlinuz-2.6.32-5-xen-amd64 dummy=dummy
root=UUID=1939b8fd-e856-4762-a6ca-76e0b9be0f36 ro
    module /boot/initrd.img-2.6.32-5-xen-amd64
}

menuentry "Xen 4.0 2.6.32.50" {
    insmod ext2
    set root=''(hd1,1)''
    multiboot /boot/xen-4.0-amd64.gz dom0_mem=512M dom0_max_vcpus=1
dom0_vcpus_pin loglvl=all guest_loglvl=all
    search --no-floppy --fs-uuid --set 1939b8fd-e856-4762-a6ca-76e0b9be0f36
    module /boot/vmlinuz-2.6.32.50 dummy=dummy
root=UUID=1939b8fd-e856-4762-a6ca-76e0b9be0f36 ro
    module /boot/initrd.img-2.6.32.50
}

I attach to this mail the two configuration files (one provided by Debian, the
other is the output of make oldconfig)

Thanks again for your help !

-- Emmanuel COURCELLE                emmanuel.courcelle@toulouse.inra.fr
L.I.P.M. (UMR CNRS-INRA 2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE


_______________________________________________
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

Emmanuel COURCELLE

2012-Jan-05 14:58 UTC

head link

Re: Re : Re : Re : Which kernel may I compile ?

David TECHER

2012-Jan-05 15:43 UTC

head link

Re : Re : Re : Re : Which kernel may I compile ?

Try  


dom0_mem=2048MB

It should be enough (do not forget ''MB'' )


you need to have enough memory to handle the init process







________________________________
 De : Emmanuel COURCELLE <emmanuel.courcelle@toulouse.inra.fr>
À : xen-users@lists.xensource.com 
Cc : David TECHER <davidtecher@yahoo.fr> 
Envoyé le : Jeudi 5 Janvier 2012 15h58
Objet : Re: [Xen-users] Re :  Re :  Re :  Which kernel may I compile ?
 

Le 05/01/2012 14:01, David TECHER a écrit : 
Emmanuel,>
>
>Do you''ve got
>
>
>"Kernel Panic - not syncing: VFS: Unable to mount root fs on
unknown-block(0,0)" ???????
>
>
>Yes David, it is this message. However I carefully executed the command:

mkinitramfs -o initrd.img-2.6.32.50 2.6.32.50, 
which does the same thing as the command explained by ubuntu.

Well, I think that the problem is that I have put some parameters on
    the xen command line, as explained here:
http://wiki.xen.org/wiki/XenBestPractices
(I did this because I had a crash of dom0 when I tried to give too
    much memory to my domU, and this indeed solved my problem).

If I use the following grub command (generated by update-grub)

echo    ''Loading Linux 2.6.32.50 ...'' multiboot      
/boot/xen-4.0-amd64.gz placeholder module  /boot/vmlinuz-2.6.32.50 placeholder
root=UUID=3bb2e67b-19c8-4916-9977-4ff87983164d ro  quiet echo   
''Loading initial ramdisk ...'' module 
/boot/initrd.img-2.6.32.50
The machine boots fine, BUT if I use the following grub command:

echo    ''Loading Linux 2.6.32.50 ...'' multiboot      
/boot/xen-4.0-amd64.gz placeholder dom0_mem=512 module  /boot/vmlinuz-2.6.32.50
placeholder root=UUID=3bb2e67b-19c8-4916-9977-4ff87983164d ro  quiet echo   
''Loading initial ramdisk ...'' module 
/boot/initrd.img-2.6.32.50
it hangs with the message Unable to mount root fs etc.
The funny thing is that everything works perfectly well with the
    initial Debian kernel (2.6.32-5-xen-amd64).

So, is there a solution, or do I have to avoid any parameter on the
    xen boot command ?


-- 
Emmanuel COURCELLE emmanuel.courcelle@toulouse.inra.fr L.I.P.M. (UMR CNRS-INRA
2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE 

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

David TECHER

2012-Jan-05 16:01 UTC

head link

Re : Re : Re : Re : Which kernel may I compile ?

The last solution is to put UUID off

vim /etc/default/grub to disable UUID


# Uncomment if you don''t want GRUB to pass "root=UUID=xxx"
parameter to Linux GRUB_DISABLE_LINUX_UUID=true

then

update-grub

if it does not succeed, I have no more suggestion

Sorry



________________________________
 De : David TECHER <davidtecher@yahoo.fr>
À : Emmanuel COURCELLE <emmanuel.courcelle@toulouse.inra.fr>;
"xen-users@lists.xensource.com" <xen-users@lists.xensource.com>
Envoyé le : Jeudi 5 Janvier 2012 16h43
Objet : Re : [Xen-users] Re :  Re :  Re :  Which kernel may I compile ?
 

Try  


dom0_mem=2048MB

It should be enough (do not forget ''MB'' )


you need to have enough memory to handle the init process






________________________________
 De : Emmanuel COURCELLE <emmanuel.courcelle@toulouse.inra.fr>
À : xen-users@lists.xensource.com 
Cc : David TECHER <davidtecher@yahoo.fr> 
Envoyé le : Jeudi 5 Janvier 2012 15h58
Objet : Re: [Xen-users] Re :  Re :  Re :  Which kernel may I compile ?
 

Le 05/01/2012 14:01, David TECHER a écrit : 
Emmanuel,>
>
>Do you''ve got
>
>
>"Kernel Panic - not syncing: VFS: Unable to mount root fs on
unknown-block(0,0)" ???????
>
>
>Yes David, it is this message. However I carefully executed the command:

mkinitramfs -o initrd.img-2.6.32.50 2.6.32.50, 
which does the same thing as the command explained by ubuntu.

Well, I think that the problem is that I have put some parameters on
    the xen command line, as explained here:
http://wiki.xen.org/wiki/XenBestPractices
(I did this because I had a crash of dom0 when I tried to give too
    much memory to my domU, and this indeed solved my problem).

If I use the following grub command (generated by update-grub)

echo    ''Loading Linux 2.6.32.50 ...'' multiboot      
/boot/xen-4.0-amd64.gz placeholder module  /boot/vmlinuz-2.6.32.50 placeholder
root=UUID=3bb2e67b-19c8-4916-9977-4ff87983164d ro  quiet echo   
''Loading initial ramdisk ...'' module 
/boot/initrd.img-2.6.32.50
The machine boots fine, BUT if I use the following grub command:

echo    ''Loading Linux 2.6.32.50 ...'' multiboot      
/boot/xen-4.0-amd64.gz placeholder dom0_mem=512 module  /boot/vmlinuz-2.6.32.50
placeholder root=UUID=3bb2e67b-19c8-4916-9977-4ff87983164d ro  quiet echo   
''Loading initial ramdisk ...'' module 
/boot/initrd.img-2.6.32.50
it hangs with the message Unable to mount root fs etc.
The funny thing is that everything works perfectly well with the
    initial Debian kernel (2.6.32-5-xen-amd64).

So, is there a solution, or do I have to avoid any parameter on the
    xen boot command ?


-- 
Emmanuel COURCELLE emmanuel.courcelle@toulouse.inra.fr L.I.P.M. (UMR CNRS-INRA
2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE 

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Emmanuel COURCELLE

2012-Jan-05 16:06 UTC

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Re: Re : Re : Re : Re : Which kernel may I compile ?

David TECHER

2012-Jan-05 23:26 UTC

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Re : Re : Re : Re : Re : Which kernel may I compile ?

Emmanuel,

To be honest, I know it since a long time and I never tried to fix it.

Xen works...that all I need :)

David



________________________________
 De : Emmanuel COURCELLE <emmanuel.courcelle@toulouse.inra.fr>
À : David TECHER <davidtecher@yahoo.fr> 
Cc : "xen-users@lists.xensource.com"
<xen-users@lists.xensource.com>
Envoyé le : Jeudi 5 Janvier 2012 17h06
Objet : Re: [Xen-users] Re : Re : Re : Re : Which kernel may I compile ?
 

Le 05/01/2012 16:43, David TECHER a écrit : 
Try  >
>
>
>dom0_mem=2048MB
>
>
>It should be enough (do not forget ''MB'' )
>
>
>
>you need to have enough memory to handle the init process
>
>
>OK, thanks, it boots now (at least on my test computer, I''ll only try
next week on the prod server)

But I have another question, may be related... or not: when I
    compile the kernel, I noticed that the modules directory is really
    huge, compared to the original Debian directory:

du -sh /lib/modules/2.6.32.50 /lib/modules/2.6.32-5-xen-amd64
1.3G    /lib/modules/2.6.32.50
96M    /lib/modules/2.6.32-5-xen-amd64
After some investigation, it appears that each .ko file is about 10 times bigger
after recompilation:

ls -l lib/modules/2.6.32.50/kernel/fs/ext4/ext4.ko 
lib/modules/2.6.32-5-xen-amd64/kernel/fs/ext4/ext4.ko
-rw-r--r-- 1 root root  526872 Oct  3 11:21
lib/modules/2.6.32-5-xen-amd64/kernel/fs/ext4/ext4.ko
-rw-r--r-- 1 root root 6553221 Jan  4 16:31
lib/modules/2.6.32.50/kernel/fs/ext4/ext4.ko
May be this is the reason why dom0 needs so much memory in the new version: do
you have any idea of how I could fix that ?


-- 
Emmanuel COURCELLE emmanuel.courcelle@toulouse.inra.fr L.I.P.M. (UMR CNRS-INRA
2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE 
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Emmanuel COURCELLE

2012-Jan-12 07:30 UTC

head link

Re: Re : Re : Re : Re : Re : Which kernel may I compile ?

Hi everybody

Here the last email about this thread: I preferred to wait several days 
before sending it, but now I am sure that everything works OK

The only real problem was a Kernel compilation problem: for an unknown 
reason, when I do:

make oldconfig

all the DEBUG related parameters are switched to Yes. I had to change 
every DEBUG_ parameter from Y to N before the kernel compilation/

This leads to a modules directory of about 90 Mb, instead of 1.4 Gb if 
the debug parameters are switched on: with such large modules you need a 
very large dom0_mem, as David suggested to me. (I presume there are also 
performance problems)

So the correct solution was to compile the kernel after switching off 
all the DEBUG_ parameters, then boot Xen as usual, and the 
dom0_mem=512MB works perfectly well.
And now I have a domU with 96Mb memory

Well, thanks again for your help !

-- 
Emmanuel COURCELLE                emmanuel.courcelle@toulouse.inra.fr
L.I.P.M. (UMR CNRS-INRA 2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE

David TECHER

2012-Jan-12 09:31 UTC

head link

Re : Re : Re : Re : Re : Re : Which kernel may I compile ?

Emmanuel,

Thanks for your mail.

It is very usefull (for me first :) ).



________________________________
 De : Emmanuel COURCELLE <emmanuel.courcelle@toulouse.inra.fr>
À : xen-users@lists.xensource.com 
Envoyé le : Jeudi 12 Janvier 2012 8h30
Objet : Re: [Xen-users] Re : Re : Re : Re : Re : Which kernel may I compile ?
 
Hi everybody

Here the last email about this thread: I preferred to wait several days before
sending it, but now I am sure that everything works OK

The only real problem was a Kernel compilation problem: for an unknown reason,
when I do:

make oldconfig

all the DEBUG related parameters are switched to Yes. I had to change every
DEBUG_ parameter from Y to N before the kernel compilation/

This leads to a modules directory of about 90 Mb, instead of 1.4 Gb if the debug
parameters are switched on: with such large modules you need a very large
dom0_mem, as David suggested to me. (I presume there are also performance
problems)

So the correct solution was to compile the kernel after switching off all the
DEBUG_ parameters, then boot Xen as usual, and the dom0_mem=512MB works
perfectly well.
And now I have a domU with 96Mb memory

Well, thanks again for your help !

-- Emmanuel COURCELLE                emmanuel.courcelle@toulouse.inra.fr
L.I.P.M. (UMR CNRS-INRA 2594/441) tel (33) 5-61-28-54-50
B.P.52627 - 31326 CASTANET TOLOSAN Cedex - FRANCE


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Xen users - Jan 2012 - Which kernel may I compile ?

Which kernel may I compile ?

Re : Which kernel may I compile ?

Re: Re : Which kernel may I compile ?

Re: Re : Which kernel may I compile ?

Re : Re : Which kernel may I compile ?

Re: Re : Re : Which kernel may I compile ?

Re : Re : Re : Which kernel may I compile ?

Re: Re : Re : Re : Which kernel may I compile ?

Re : Re : Re : Re : Which kernel may I compile ?

Re : Re : Re : Re : Which kernel may I compile ?

Re: Re : Re : Re : Re : Which kernel may I compile ?

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