[Buildroot] [PATCH] package/systemd: Optionally disable hwdb

[Yann E. MORIN <yann.morin.1998@free.fr>]

Marcin, All,

On 2016-04-15 12:46 +0200, Marcin Niestroj spake thusly:
> By default hwdb files are installed in /usr/lib/udev/hwdb.d
> Currently they take about ~5MB. After first boot, systemd-hwdb tool
> parses them and creates a binary in /etc/udev/hwdb.bin, which takes
> another ~6.5MB.
> 
> In case of initramfs images, hwdb parsing is done every boot. This adds
> about 2-3 seconds to boot time in case of rootfs on SDHC class 10
> card (benchmarked with am335x board). NAND boot takes even longer.

So that's where my boot time goes! ;-)

> Add config option to disable hwdb in systemd, for smaller images and
> better boot performance.
> 
> Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>

I'm looking at all systemd-related pending patches, since I'm working on
cleaning up our systemd handling...

I have had a look at the systemd code to update the hwdb, and it is not
trivially replaced, so we would indeed need a host-systemd if we wanted
to generate the hwdb at build time.

I don't think this warrants the complexity of a host-systemd, however...

Yet, I'd like to know what would be the impact of not having hwdb
support at runtime. Care to shed some light, please?

Otherwise:

Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

Regards,
Yann E. MORIN.

> ---
>  package/systemd/Config.in  | 11 +++++++++++
>  package/systemd/systemd.mk |  6 ++++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/package/systemd/Config.in b/package/systemd/Config.in
> index 97d48c4..324e884 100644
> --- a/package/systemd/Config.in
> +++ b/package/systemd/Config.in
> @@ -84,6 +84,17 @@ config BR2_PACKAGE_SYSTEMD_JOURNAL_GATEWAY
>  
>  	  http://www.freedesktop.org/software/systemd/man/systemd-journal-gatewayd.service.html
>  
> +config BR2_PACKAGE_SYSTEMD_HWDB
> +	bool "enable hwdb installation"
> +	default y
> +	help
> +	  Enables hardware database installation to /usr/lib/udev/hwdb.d
> +
> +	  Disabling this option improves first boot time (or every boot
> +	  time in case of initramfs images) and saves several MB space.
> +
> +	  https://www.freedesktop.org/software/systemd/man/hwdb.html
> +
>  config BR2_PACKAGE_SYSTEMD_BINFMT
>  	bool "enable binfmt tool"
>  	help
> diff --git a/package/systemd/systemd.mk b/package/systemd/systemd.mk
> index 79e657e..29b62c0 100644
> --- a/package/systemd/systemd.mk
> +++ b/package/systemd/systemd.mk
> @@ -127,6 +127,12 @@ else
>  SYSTEMD_CONF_OPTS += --disable-microhttpd
>  endif
>  
> +ifeq ($(BR2_PACKAGE_SYSTEMD_HWDB),y)
> +SYSTEMD_CONF_OPTS += --enable-hwdb
> +else
> +SYSTEMD_CONF_OPTS += --disable-hwdb
> +endif
> +
>  ifeq ($(BR2_PACKAGE_SYSTEMD_BINFMT),y)
>  SYSTEMD_CONF_OPTS += --enable-binfmt
>  else
> -- 
> 2.8.0
> 
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