On Mon, Oct 06, 2025 at 09:42:20AM +0200, Morten Brørup wrote: > Bruce, > > cpu_set_t is a fixed size array, with the size CPU_SETSIZE. > This is part of libc. > > However, the kernel may be built with support for a different number of CPUs. > This means that e.g. sched_getaffinity() will fail with EINVAL if cpusetsize > is smaller than the number of CPUs the kernel was built for. > For more information, refer to the description about "Dynamically sized CPU > sets" here: > https://linux.die.net/man/3/cpu_alloc_size > > With this series, consider ensuring that all DPDK functions taking a cpu set > parameter also take a cpu set size parameter, to align with kernel APIs. > E.g.: > int sched_getaffinity(pid_t pid, > size_t cpusetsize, cpu_set_t *mask), and > void CPU_ZERO_S(size_t setsize, cpu_set_t *set), > instead of: > void CPU_ZERO(cpu_set_t *set). >
Ok, that seems a feasible change. > <feature creep> > Consider not using fixed size cpu sets (and CPU_SETSIZE) at all, but > dynamically allocated cpu sets. > </feature creep> > Will have to see what that involves. If it's fairly easy, I'll give it a go, but we are rather late in this release cycle, so if it's taking too long I'll have to give this bit a miss. /Bruce
