On Thu, Jan 9, 2020 at 3:34 AM Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > On Thu, 2020-01-09 at 17:18 +0800, Yan, Zheng wrote: > > > +bool enable_async_dirops; > > > +module_param(enable_async_dirops, bool, 0644); > > > +MODULE_PARM_DESC(enable_async_dirops, "Asynchronous directory operations enabled"); > > > + > > > > why not use mount option > > > > I'm open to suggestions here. > > I mostly put this in originally to help facilitate performance testing. > A module option makes it easy to change this at runtime (without having > to remount or anything). > > That said, we probably _do_ want to have a way for users to enable or > disable this feature. We'll probably want this disabled by default > initially, but I can forsee that changing once get more confidence. > > Mount options are a bit of a pain to deal with over time. If the > defaults change, we need to document that in the manpages and online > documentation. If you put a mount option in the fstab, then you have to > deal with breakage if you boot to an earlier kernel that doesn't support > that option. > > My thinking is that we should just use a module option initially (for > the really early adopters) and only convert that to a mount option as > the need for it becomes clear. Module option makes sense. A mount option to disable async ops would also make sense. I do not think the default behavior should be off-by-default. (Someday perhaps the kernel will be smart enough to also digest the ceph configs delivered through the monitors...) -- Patrick Donnelly, Ph.D. He / Him / His Senior Software Engineer Red Hat Sunnyvale, CA GPG: 19F28A586F808C2402351B93C3301A3E258DD79D
