Re: What belongs in the Debian cloud kernel?
On 4/4/20 1:34 AM, Noah Meyerhans wrote:
> On Wed, Apr 01, 2020 at 03:15:37PM -0400, Noah Meyerhans wrote:
>> There are open bugs against the cloud kernel requesting that
>> configuration options be turned on there. [1][2][3]
>
> <snip>
>
>> 1. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=952108
>> 2. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=955366
>> 3. https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=955232
>
> So, the discussion thus far has focused on these specific requests more
> than I had hoped. So for now, so we can deal with the current requests,
> here's what happens if we enable them:
>
> These are the kernel .config changes:
> +CONFIG_VHOST_SCSI=m
> +CONFIG_KSM=y
> +CONFIG_NET_9P=m
> +CONFIG_NET_9P_VIRTIO=m
> +# CONFIG_NET_9P_XEN is not set
> +# CONFIG_NET_9P_DEBUG is not set
> +CONFIG_TARGET_CORE=m
> +CONFIG_TCM_IBLOCK=m
> +CONFIG_TCM_FILEIO=m
> +CONFIG_TCM_PSCSI=m
> +CONFIG_TCM_USER2=m
> +# CONFIG_LOOPBACK_TARGET is not set
> +CONFIG_ISCSI_TARGET=m
> +# CONFIG_XEN_SCSI_BACKEND is not set
> +CONFIG_9P_FS=m
> +CONFIG_9P_FSCACHE=y
> +CONFIG_9P_FS_POSIX_ACL=y
> +CONFIG_9P_FS_SECURITY=y
> +CONFIG_XXHASH=y
>
> Because CONFIG_KSM changes statically linked code, it results in a size
> increase of roughly 12 kB of the compressed kernel. The uncompressed
> kernel increases by about 852 kB in size. The boot time appears to be
> unchanged. I don't like the size increase, but this feature is enabled
> everywhere else and apparently does break some users if it's disabled,
> so we should enable it.
>
> The kernel package installed size increases by roughly 2 MB due to the
> additional modules we generate for 9P and VHOST_SCSI.
>
> So, I think the answer for these specific requests can be affirmative.
> The cost is small enough that if these features are useful to somebody,
> then we might as well enable them.
>
> noah
Thanks for taking the time to investigate.
+1 to what you wrote.
Cheers,
Thomas Goirand (zigo)
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