On Thu, Oct 1, 2015 at 9:30 PM, Steve Dickson <ste...@redhat.com> wrote: > > > On 10/01/2015 09:24 AM, Kay Sievers wrote: >> On Wed, Sep 30, 2015 at 10:49 PM, Steve Dickson <ste...@redhat.com> wrote: >>> Is there a way for systemd to monitor kernel process? >>> By monitor I mean the existence. >> >> No, and there is no plan to do anything like that. >> >> Kernel tasks are kernel internals, and userspace must not make any >> assumptions about them. They can come and go at any time between any >> kernel versions. >> >> Custom tools can do what they need, but systemd should not offer to do >> that to users. > First all thanks for the response > > kernel process in question is nfsd. The number of thread > is kept in /proc/fs/nfsd/threads. > > So the idea would be doing a systemctl status nfsd > and number in /proc/fs/nfsd/threads is zero the > service would be deactive. An non-zero number the > service would active. > > Is this something systemd could be used for?
No, not directly. There is no facility to watch /proc or any other similar interface for such changes. Plain /proc directories are just not capable of providing event information to userspace. The kernel's nfs implementation would need a character device where events are send out, or possibly a poll()able file in /proc, or something in /sys/devices/, or a similar approach, where udev can react to. Such interface could be used to signal systemd that userspace should react to state changes in the kernel. Kay _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
