On 09/02/2022 11:37, Jan Beulich wrote: > [CAUTION - EXTERNAL EMAIL] DO NOT reply, click links, or open attachments > unless you have verified the sender and know the content is safe. > > On 09.02.2022 11:31, Jane Malalane wrote: >> This is not a bug. The xen cmdline can request both a NUMA restriction >> and a vcpu count restriction for Dom0. The node restriction wil always >> be respected which might mean either using dom0_max_vcpus < >> opt_dom0_max_vcpus_max > > This is quite normal a case if a range was specified, or did you mean > opt_dom0_max_vcpus_min? But min and max get applied last anyway, so > those always override what was derived from dom0_nr_pxms. Yes, I was just giving context here for what I say in the following sentence. Maybe this became more confusing than helpful. > >> or using more vCPUs than pCPUs on a node. In >> the case where dom0_max_vcpus gets capped at the maximum number of >> pCPUs for the number of nodes chosen, it can be useful particularly >> for debugging to print a message in the serial log. > > The number of vCPU-s Dom0 gets is logged in all cases. And the > reasons why a certain value is uses depends on more than just > the number-of-nodes restriction. Maybe I should have said 'Dom0 "receiving" %d vCPUS' instead of "using" in the serial log, in which case I can amend that to make it clearer (that ofc if we still want this change)? I therefor wonder whether the > wording as you've chosen it is potentially misleading, and > properly expressing everything in a single message is going to > be quite a bit too noisy. Furthermore ... > >> --- a/xen/arch/x86/dom0_build.c >> +++ b/xen/arch/x86/dom0_build.c >> @@ -240,6 +240,11 @@ unsigned int __init dom0_max_vcpus(void) >> if ( max_vcpus > limit ) >> max_vcpus = limit; >> >> + if ( max_vcpus < opt_dom0_max_vcpus_max && max_vcpus > >> opt_dom0_max_vcpus_min ) >> + printk(XENLOG_INFO "Dom0 using %d vCPUs conflicts with request to >> use" >> + " %d node(s), using up to %d vCPUs\n", >> opt_dom0_max_vcpus_max, >> + dom0_nr_pxms, max_vcpus); > > ... the function can be called more than once, whereas such a > message (if we really want it) would better be issued just once. Yes, that is true and this code would have to live outside of dom0_build.c. > > To answer your later reply to yourself: I think printk() is fine > here (again assuming we want such a message in the first place); > it's a boot-time-only message after all. > Okay.
Thank you, Jane.
