IPI interrupt

IPI： Inter processor interrupt （Inter-Processor Interrupt,IPI） It's a special type interrupt , That is to say Multiprocessor systems in , If the interrupt processor needs actions from other processors , The act of interrupting from one processor to another . Actions that may be required include ： Refresh the memory management unit cache of other processors , Such as translation backup buffer , When a processor changes memory mapping ; downtime , When the system is shut down by a processor .

IPI Interrupts are multicore CPU In the system CPU The only way to communicate with each other .

Three IPI：

CALL_FUNCTION_VECTOR （ vector 0xfb）

To all CPU, But not the sender , Force these CPU Run the function passed by the sender , The corresponding interrupt handler is called call_function_interrupt(), for example , The address is stored in the social variable call_data Functions passed in , May force all other CPU All stop , They may also be forced to set the contents of the memory type range register . Usually , This interrupt is sent to all CPU, But through smp_call_function() Executing the calling function CPU With the exception of .

RESCHEDULE_VECTOR （ vector 0xfc）

When one CPU When receiving this type of interrupt , The corresponding handler limits itself to answering interrupts , When returning from an interrupt , All rescheduling runs automatically .

INVALIDATE_TLB_VECTOR （ vector 0xfd）（ In a multicore system , Each processor corresponds to TLB Keep in sync ）

To all CPU, But not the sender , Force their conversion backup buffer TLB Become invalid . The corresponding handler refreshes some of the processor TLB Table item .