[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v7 07/11] pvqspinlock, x86: Allow unfair queue spinlock in a XEN guest
On Mar 20, 2014 11:40 PM, Waiman Long <waiman.long@xxxxxx> wrote: > > On 03/19/2014 04:28 PM, Konrad Rzeszutek Wilk wrote: > > On Wed, Mar 19, 2014 at 04:14:05PM -0400, Waiman Long wrote: > >> This patch adds a XEN init function to activate the unfair queue > >> spinlock in a XEN guest when the PARAVIRT_UNFAIR_LOCKS kernel config > >> option is selected. > >> > >> Signed-off-by: Waiman Long<Waiman.Long@xxxxxx> > >> --- > >>ÂÂ arch/x86/xen/setup.c |ÂÂ 19 +++++++++++++++++++ > >>ÂÂ 1 files changed, 19 insertions(+), 0 deletions(-) > >> > >> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c > >> index 0982233..66bb6f5 100644 > >> --- a/arch/x86/xen/setup.c > >> +++ b/arch/x86/xen/setup.c > >> @@ -625,3 +625,22 @@ void __init xen_arch_setup(void) > >>ÂÂ numa_off = 1; > >>ÂÂ #endif > >>ÂÂ } > >> + > >> +#ifdef CONFIG_PARAVIRT_UNFAIR_LOCKS > >> +/* > >> + * Enable unfair lock if running in a Xen guest > >> + */ > >> +static __init int xen_unfair_locks_init_jump(void) > >> +{ > >> + /* > >> + * Disable unfair lock if not running in a PV domain > >> + */ > >> + if (!xen_pv_domain()) > >> + return 0; > > I would just make this 'xen_domain'. Not sure why you need > > to have it only for PV while the PVHVM guests can also use it? > > The compilation of the setup.c file should have implied xen_domain > already (at least HVM). The check is added to make sure that unfair lock > won't be enabled on bare metal. As for PVHVM, is there a way to detect > it is running as such which is distinct from HVM? Xen_domain() should cover PVHVM and PV. > > > Would it also make sense to use the same printk statement > > that the KVM has? > > > > Yes, I can add a printk statement like KVM. > > -Longman _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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