On Wed, 11 Nov 2020 12:34:51 -0800 Erik Kline <e...@loon.com> wrote: > On Wed, Nov 11, 2020 at 11:55 AM Stephen Hemminger > <step...@networkplumber.org> wrote: > > > > On Wed, 11 Nov 2020 11:02:14 -0800 > > Cong Wang <xiyou.wangc...@gmail.com> wrote: > > > > > On Tue, Nov 10, 2020 at 8:32 PM 杜英杰 <leon...@pku.edu.cn> wrote: > > > > > > > > I want to use inotify to monitor /sys/class/net//operstate to detect > > > > status of a iface in real time. > > > > when I ifdown && ifup eth3, the content of operstate changed, > > > > but the file's Modify time didn't change. > > > > I don't know the reason, is there any file which can be monitored by > > > > inotify to get iface status in real time? > > > > Much appreciation for any advice! > > > > > > You need to listen to netdev netlink messages for changes like > > > this. These messages are generated in real-time. > > > > The /sys and /proc are pseudo-filesystems. The file modify time and inotify > > do not work > > as expected on these files. Cong is right you need to use netlink for this. > > > > Related question: could/should modify time and/or inotify be made to > work? I genuinely don't know if that would even be possible (separate > from "desirable").
The problem is lots of data changes in /proc and /sys all the time, like every counter value. So having any kind of notification would be a major performance hit.
