Re: [Xen-devel] [PATCH v5 3/4] VT-d PI: restrict the number of vcpus in a given pcpu's PI blocking list

>>> On 16.08.17 at 07:14, wrote: > +static inline bool pi_over_limit(unsigned int cpu) > +{ > +/* Compare w/ constant first to save a division and an add */ > +if ( likely(read_atomic(_cpu(vmx_pi_blocking, cpu).counter) <= > +PI_LIST_FIXED_LIMIT) ) > +

[Xen-devel] [PATCH v5 3/4] VT-d PI: restrict the number of vcpus in a given pcpu's PI blocking list

Currently, a blocked vCPU is put in its pCPU's pi blocking list. If too many vCPUs are blocked on a given pCPU, it will incur that the list grows too long. After a simple analysis, there are 32k domains and 128 vcpu per domain, thus about 4M vCPUs may be blocked in one pCPU's PI blocking list.