Re: hundreds of mount --bind mountpoints?

Alexander Viro
2001-04-22T16:41:38Z

On Sun, 22 Apr 2001, David L. Parsley wrote:

> Hi,
>
> I'm still working on a packaging system for diskless (quasi-embedded)
> devices. The root filesystem is all tmpfs, and I attach packages inside
> it. Since symlinks in a tmpfs filesystem cost 4k each (ouch!), I'm
> considering using mount --bind for everything. This appears to use very
> little memory, but I'm wondering if I'll run into problems when I start
> having many hundreds of bind mountings. Any feel for this?

Memory use is sizeof(struct vfsmount) per binding. In principle, you can get
in trouble when size of /proc/mount will get past 4Kb - you'll get only
first 4 (actually 3, IIRC) kilobytes, so stuff that relies on the contents
of said file may get unhappy. It's fixable, though.