Messages in this thread |  | | | Date | Mon, 07 Feb 2011 18:26:43 +0200 | | From | Avi Kivity <> | | Subject | Re: [PATCH] KVM: x86: Convert tsc_write_lock to raw_spinlock |
| |
On 02/07/2011 05:58 PM, Jan Kiszka wrote: > On 2011-02-07 16:52, Avi Kivity wrote: > > On 02/07/2011 05:38 PM, Jan Kiszka wrote: > >>> > >>> I don't know as it is allowed to sleep, it doesn't call any sleeping > >>> functions to my knowledge. What worries me in the RT case is that the > >>> spinlock acquired for hardware_enable might be preempted and run on > >>> another CPU, which obviously isn't what you want. > >> > >> I see now, there are calls to raw_smp_processor_id. > >> > >> I think it's best to make this a raw lock. At this chance, some > >> read-only users of vm_list should be rcu'ified. Will have a look. > > > > vm_list is rarely used, for either read or write. I don't see the need > > to rcu it. > > Avoid that code under this lock expands the preempt-disabled period, > specifically under -rt, and specifically as the number of objects over > which we loop is user-defined.
Good point; even under non-rt.
(well, actually, cpufreq_notifier and kvm_arch_hardware_enable are already non preemptible, and the stats code should just go away?)
-- error compiling committee.c: too many arguments to function
|  |