Re: [PATCHv2/RFC] kvm/irqchip: Speed up KVM_SET_GSI_ROUTING

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Il 16/01/2014 13:44, Christian Borntraeger ha scritto:
> I converted most of the rcu routines to srcu. Review for the unconverted
> use of hlist_for_each_entry_rcu, hlist_add_head_rcu, hlist_del_init_rcu
> is necessary, though. They look fine to me since they are protected by
> outer functions.

They are fine because they do not have lockdep checks
(hlist_for_each_entry_rcu uses rcu_dereference_raw rather than
rcu_dereference, and write-sides do not do rcu lockdep at all).

> In addition, we should also discuss if a global srcu (for all guests) is
> fine.

I think it is.  It is already way cheaper than it used to be, and we're
hardly relying on the "sleepable" part of srcu.  We just want its faster
detection of grace periods.  One instance should be fine because our
read sides are so small and mostly they are not even preemptable.

Thanks for writing the patch!

Paolo
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux