Re: [RFC 0/2] To introduce xenwatch multithreading (xen mtwatch)

From: Wei Liu
Date: Mon Apr 23 2018 - 10:11:04 EST


On Sat, Apr 07, 2018 at 07:25:53PM +0800, Dongli Zhang wrote:
> About per-domU xenwatch thread create/destroy, a new type of xenstore node is
> introduced: '/local/domain/0/mtwatch/<domid>'.
>
> Suppose the new domid id 7. During the domU (domid=7) creation, the xen
> toolstack writes '/local/domain/0/mtwatch/7' to xenstore before the insertion
> of '/local/domain/7'. When the domid=7 is destroyed, the last xenstore
> operation by xen toolstack is to remove '/local/domain/0/mtwatch/7'.
>
> The dom0 kernel subscribes a watch at node '/local/domain/0/mtwatch'. Kernel
> thread [xen-mtwatch-7] is created when '/local/domain/0/mtwatch/7' is inserted,
> while this kernel thread is destroyed when the corresponding xenstore node is
> removed.

Instead of inventing yet another node, can you not watch /local/domain
directly?

Wei.