On Tue, May 14, 2019 at 10:24 AM Ulrich Windl < ulrich.wi...@rz.uni-regensburg.de> wrote:
> >>> Andrei Borzenkov <arvidj...@gmail.com> schrieb am 14.05.2019 um 08:40 > in > Nachricht > <CAA91j0VyN+972Q+D8b5YO1s04JM0BuxcHz_HN8fq9=-h616...@mail.gmail.com>: > > On Tue, May 14, 2019 at 9:35 AM Ulrich Windl > > <ulrich.wi...@rz.uni-regensburg.de> wrote: > > > >> > >> I knew that. It doesn't answer _why_ /var/run is obsolete. > >> > > > > /var/run needs /var which is not guaranteed to be there when you need > > it which complicates things. > > Thanks, > > I'll start a new thread on this (I wanted to ask anyway): > AFAIK systemd does socket communication a lot, while old init was happy > with just a root filesystem. > So I wonder how this Hen-Egg_Problem is solved: Systemd needs a socket to > operate, but to provide the infrastructure, systemd would need the socket > do do so. > Or expressed in other words: How can systemd create /run when it needs > /run to operate? > 1. systemd performs these actions during initialization, before switching to the main loop. 2. systemd can operate without any sockets; it connects to D-Bus for control once it becomes available, but it's not a runtime requirement. > The corresponding question would be for shutdown: How will systemd unmount > /run? OK, if ist a ramdisk, it's not really needed. > The 'systemd-shutdown' binary doesn't unmount /run or /, it keeps the former and remounts the latter read-only. (It can optionally pivot_root *to* /run, though, and unmount / using the "shutdown initramfs" feature.) > > Another related question is that of shutdown in general: > For startup the semantics of Before= and After= are clear, but isn't it > just reverted for shutdown? That is if "M" has "After=X" and "Before=Y", > does that imply that Y is stopped before M will be stzopped, and M will be > stopped before X is? > Yes, it is reversed on shutdown. > > From the experience how fast shutdown happens, I don't think it's like > that. > Usually killing processes is faster than loading them from disk. -- Mantas Mikulėnas
_______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/systemd-devel
