Re: [PATCH 3/3] autofs - fix AT_NO_AUTOMOUNT not being honored

From: Ian Kent
Date: Tue Nov 28 2017 - 21:29:28 EST


On 29/11/17 10:13, Mike Marion wrote:
> On Wed, Nov 29, 2017 at 12:17:27PM +1100, NeilBrown wrote:
>
>> How big do people see /proc/self/mount* getting? What size reads
>> does 'strace' show the various programs using to read it?
>
> We already have line counts into 5 figures. This wasn't an issue until
> the change of /etc/mtab to a link. The large count is due to our large
> direct automount maps.
>

And, admittedly, the testing I was doing was with 15k+ size maps.

Of course it's necessary to have this number of mounts to see serious
problems which is easiest to do with large direct mount maps.

The thing that's different now is that before applications started
using /proc directly for mount table information using mount(2)
instead of mount(8) was enough to prevent the mount entries from
being added to the table seen by applications.

Ian