On Fri, Jun 17, 2011 at 12:58:03AM +0200, Ingo Molnar wrote: > > * Andi Kleen <ak@xxxxxxxxxxxxxxx> wrote: > > > > There's a crazy solution for that: the idle thread could process > > > RCU callbacks carefully, as if it was running user-space code. > > > > In Ben's kernel NFS server case the system may not be idle. > > An always-100%-busy NFS server is very unlikely, but even in the > hypothetical case a kernel NFS server is really performing system > calls from a kernel thread in essence. If it doesn't do it explicitly > then its main loop can easily include a "check RCU callbacks" call. As long as they make sure to call it in a clean environment: no locks held and so on. But I am a bit worried about the possibility of someone forgetting to put one of these where it is needed -- it would work just fine for most workloads, but could fail only for rare workloads. That said, invoking RCU core/callback processing from the scheduler context certainly sounds like an interesting way to speed up grace periods. Thanx, Paul -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>