On 2023-09-15, Enlin Mu <enlin...@outlook.com> wrote: > Sometimes we want to print cpu id of printk() messages to consoles > > diff --git a/include/linux/threads.h b/include/linux/threads.h > index c34173e6c5f1..6700bd9a174f 100644 > --- a/include/linux/threads.h > +++ b/include/linux/threads.h > @@ -34,6 +34,9 @@ > #define PID_MAX_LIMIT (CONFIG_BASE_SMALL ? PAGE_SIZE * 8 : \ > (sizeof(long) > 4 ? 4 * 1024 * 1024 : PID_MAX_DEFAULT)) > > +#define CPU_ID_SHIFT 23 > +#define CPU_ID_MASK 0xff800000
This only supports 256 CPUs. I think it doesn't make sense to try to squish CPU and Task IDs into 32 bits. What about introducing a caller_id option to always only print the CPU ID? Or do you really need Task _and_ CPU? John Ogness
