Hi Namhyung, On Fri, Sep 20, 2019 at 1:47 AM Namhyung Kim <[email protected]> wrote: > > Hello Song, > > On Thu, Sep 19, 2019 at 3:43 PM Song Liu <[email protected]> wrote: > > > Sharing some offline discussions with Tejun. > > > > ino in current kernfs is not a good unique ID for cgroup, because it doesn't > > increase monotonically. So we need to improve kernfs. > > > > For 64-bit, we can make the ino monotonic, and use it as the ID. > > For 32-bit, we need to make the ino monotonic. and use <ino> and <gen> > > as the 64-bit ID. > > Thanks for the sharing information! For 32-bit, while the ino itself is not > monotonic, gen << 32 + ino is monotonic right? I think we can use the > same logic of kernfs id allocation, but not sure what the problem Tejun > mentioned before is.
How would we manage gen here? One way that works is: 1. make ino monotonic, 2. increase gen when 32-bit ino overflows I think current kernfs id is not monotonic, so it can be reused before overflow. Thanks, Song
