On Tue, Nov 20, 2012 at 2:06 AM, Lennart Poettering <lenn...@poettering.net> wrote: > On Mon, 19.11.12 08:13, Mantas Mikulėnas (graw...@gmail.com) wrote: > >> On Mon, Nov 19, 2012 at 8:01 AM, Mantas Mikulėnas <graw...@gmail.com> wrote: >> > Anything that is written to /sys/module/*/parameters goes to >> > modprobe.d(5) -- again, to be applied when the module is inserted, not >> > at some fixed point: >> > >> > https://github.com/vodik/powersave/blob/master/modprobe.d/powersave.conf >> > >> > Use sysctl.conf(5) for settings under /proc/sys: >> > >> > https://github.com/vodik/powersave/blob/master/sysctl.d/powersave.conf >> >> This reminded me that systemd-sysctl doesn't properly handle >> sysctl.conf entries that depend on the presence of modules loaded by >> modules-load.d... >> >> In particular, I was having problems with: >> >> net.ipv4.tcp_allowed_congestion_control = cubic reno lp >> >> This setting is required to allow non-root programs (the Transmission >> BitTorrent daemon in particular) to use the "lowest priority" >> congestion control algorithm. >> >> However, if the "tcp_lp" module is not yet loaded, the write to >> /proc/sys is simply refused with EINVAL (if I remember correctly). >> >> And if the module is loaded later (or not loaded manually), without >> the sysctl setting being updated, Transmission receives EPERM when it >> calls setsockopt(TCP_CONGESTION). >> >> This doesn't affect TCPCongestion= in systemd socket units, since root >> is allowed to set any algorithm, and the module is simply loaded on >> demand when systemd asks for it... >> >> How can this be fixed? > > Hmm, whenever a module is loaded this also generates udev events, maybe > for this specific case we should add a udev rule that tries to write the > sysctl again after the module was successfully loaded?
There would probably be too many modules even for this sysctl :/ Now that I think of it, it would be nicer if setting the sysctl autoloaded the modules... -- Mantas Mikulėnas _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
