Re: How to speed up detection of emmc partition and mount the filesystem

On 2/4/19 7:22 PM, Petr wrote:

Hello,

I have custom linux on embedded machine generated with Buildroot using  emmc drive which contains  root filesystem on /dev/mmcblk0p2 and application data on  /dev/mmcblk0p4. The root fileystem is mounted pretty quickly, but the application data are mounted about 1.7s after systemd starts, the main reason is that the mmcbl0p4 is found by systemd after 1.4s. As a workaround I created service that is executed right after the local-fs-pre.target which execute "mount /dev/mmcblk0p4 /app" and that works, but I would like to know if there is correct way how to tell systemd that I want to mount the root fs and application fs sooner than everything else (I believe that what I want is to tell systemd to mount /dev/mmcblk0p4 without waiting for udev to find /dev/mmcblk0p4 as new device and start auto mount).

Hmm... your solution could be a simple type mount unit which is ordered before the local-fs-pre.target but maybe not.

+ there are two type of embedded paths in this world those that are super tiny resource constrained and those that are not.

Former you dont use systemd for but instead some linux micro platform usually tied to or associated with internet of terror devices ( IoT ) like Soletta project, the latter you do use systemd for but only after systemd has been put on a diet so you will need to provide proper context here as in what that custom embedded devices does or is trying to do and why you need to shave those 1.4s off, what's the problem you are trying to solve with it?

JBG