On Fri, Feb 16, 2018 at 7:59 AM, Francesco Picciariello via
iovisor-dev <[email protected]> wrote:
> Hello all,
> Is there a way to receive asynchronous notification each time an eBPF map is
> modified?

When map is modified in kernel, you can send something into a ring buffer
and userspace can poll on this ring buffer to get notification.

>
> I used bpf_obj_pin() in order to save a specific map on filesystem, and I
> called linux inotify() on the pinned object.
>
> The inotify API provides a mechanism for monitoring filesystem events, and
> the goal is to notice when a pinned eBPF map is modified, but it seems
> inotify() does not work properly with bpf filesystem. In fact it's able to
> detect the creation and the deletion, but not the modification of the pinned
> object.

The inotify takes vfs_read/write for read/write operations.
Here bpf map read/write happens inside
bpf program, or through bpf syscall, and hence inotify mechanism won't work.

>
> Regards.
>
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