# genkernel compiling issues?

## pmam

I am new to genkernel and have some issues. So far I used this command to compile:

```
genkernel --menuconfig all
```

However it takes very long time to compile. Sometimes it is only small change in menuconfig, without changing modules, so I tried to use this command:

```
genkernel --menuconfig bzImage
```

It  took much less time however it caused to booting problem – don’t know why?

So I chrooted and compiled again with “all” option and booting issue was solved. Maybe it is due to this messages I get each time compiling kernel?

```
Kernel compiled successfully!

* Required Kernel Parameters:

*     root=/dev/$ROOT

*     Where $ROOT is the device node for your root partition as the

*     one specified in /etc/fstab
```

Looks that my /etc/fstab is ok but maybe need to change something:

```
/dev/sda2      /boot      ext4      defaults,noatime   0 2

/dev/sda3       none      swap      sw         0 0

/dev/sda5      /      ext4      noatime         0 1

/dev/sda6      /home      ext4      noatime         0 2
```

There is another message that I guess can be ignored cause I don’t use  initramfs.:

```
* If you require Genkernel's hardware detection features; you MUST

* tell your bootloader to use the provided INITRAMFS file.
```

Same regarding this message:

```
* WARNING... WARNING... WARNING...

* Additional kernel cmdline arguments that *may* be required to boot properly...

* With support for several ext* filesystems available, it may be needed to

* add "rootfstype=ext3" or "rootfstype=ext4" to the list of boot parameters.
```

Anyway - Please advise if need to refer to these messages and how can reduce compiling time!

----------

## Kosmas

Hi pmam,

First of all, if you compile just the bzimage, aka the kernel, then the modules and the initram do not get created and thus you will have problems booting up.

Secondly, you can reduce compiling time by not cleaning the kernel tree every time genkernel runs.

This can be done either by removing

CLEAN="yes"

in the /etc/genkernel.conf file, or running genkernel like this:

genkernel --menuconfig --no-clean all

You can then expore more options in the genkernel util and the config file and make it suit your needs.

Hope I helped.

Kosmas.

----------

## krinn

I never use genkernel myself, but kernel could be build faster adding more threads when building it, an option i don't know how you can pass it to genkernel.

Basically you just change make with a make -jX (where X is threads #)

Ask someone or find yourself how it could be pass to genkernel.

----------

## bunder

If you're using grub, you can probably ignore all those messages since it builds your kernel line automatically when you run grub-mkconfig.

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## NeddySeagoon

pmam,

Its always safe to ignore

```
* WARNING... WARNING... WARNING...

* Additional kernel cmdline arguments that *may* be required to boot properly...

* With support for several ext* filesystems available, it may be needed to

* add "rootfstype=ext3" or "rootfstype=ext4" to the list of boot parameters.
```

The rootfstype= entry on the kernel cmdline stops the kernel guessing the root fs type and messages like 

```
[    4.584436] EXT4-fs (dm-10): couldn't mount as ext3 due to feature incompatibilities

[    4.584841] EXT4-fs (dm-10): couldn't mount as ext2 due to feature incompatibilities
```

do not appear in dmesg.

When you don't tell the kernel rootfstype=, it tries all the available filesystem drivers until one works.

----------

