On Mon, Jun 07, 2021 at 12:31:47PM +0200, Christian Brauner wrote: > On Sat, Jun 05, 2021 at 10:47:07PM +0800, Menglong Dong wrote: [...] > > > > I think it's necessary, as I explained in the third patch. When the rootfs > > is a block device, ramfs is used in init_mount_tree() unconditionally, > > which can be seen from the enable of is_tmpfs. > > > > That makes sense, because rootfs will not become the root if a block > > device is specified by 'root' in boot cmd, so it makes no sense to use > > tmpfs, because ramfs is more simple. > > > > Here, I make rootfs as ramfs for the same reason: the first mount is not > > used as the root, so make it ramfs which is more simple. > > Ok. If you don't mind I'd like to pull and test this before moving > further. (Btw, I talked about this at Plumbers before btw.) > What did you use for testing this? Any way you can share it? Ok, no problem definitely. I tested this function in 3 way mainly: 1. I debug the kernel with qemu and gdb, and trace the the whole process, to ensure that there is no abnormal situation. 2. I tested pivot_root() in initramfs and ensured that it can be used normally. What's more, I also tested docker and ensured container can run normally without 'DOCKER_RAMDISK=yes' set in initramfs. 3. I tried to enable and disable CONFIG_INITRAMFS_MOUNT, and ensured that the system can boot successfully from initramfs, initrd and sda. What's more, our team is going to test it comprehensively, such as ltp, etc. Thanks! Menglong Dong
